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Article

Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania

by
John Lobulu
1,2,*,
Hussein Shimelis
1,
Mark D. Laing
1,
Arnold Angelo Mushongi
3 and
Admire Isaac Tichafa Shayanowako
1
1
African Centre for Crop Improvement (ACCI), School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Pietermaritzburg 3209, South Africa
2
Tumbi Centre (TARI—Tumbi), Tanzania Agricultural Research Institute, Tabora P.O. Box 306, Tanzania
3
TARI—Ilonga Centre, Kilosa P.O. Box 33, Tanzania
*
Author to whom correspondence should be addressed.
Agronomy 2021, 11(5), 1004; https://doi.org/10.3390/agronomy11051004
Submission received: 30 March 2021 / Revised: 28 April 2021 / Accepted: 3 May 2021 / Published: 18 May 2021
Versions Notes

Abstract

:
Striga species cause significant yield loss in maize varying from 20 to 100%. The aim of the present study was to screen and identify maize genotypes with partial resistance to S. hermonthica (Sh) and S. asiatica (Sa) and compatible with Fusarium oxysporum f. sp. strigae (FOS), a biocontrol agent. Fifty-six maize genotypes were evaluated for resistance to Sh and Sa, and FOS compatibility. Results showed that FOS treatment significantly (p < 0.001) enhanced Striga management compared to the untreated control under both Sh and Sa infestations. The mean grain yield was reduced by 19.13% in FOS-untreated genotypes compared with a loss of 13.94% in the same genotypes treated with FOS under Sh infestation. Likewise, under Sa infestation, FOS-treated genotypes had a mean grain yield reduction of 18% while untreated genotypes had a mean loss of 21.4% compared to the control treatment. Overall, based on Striga emergence count, Striga host damage rating, grain yield and FOS compatibility, under Sh and Sa infestations, 23 maize genotypes carrying farmer preferred traits were identified. The genotypes are useful genetic materials in the development of Striga-resistant cultivars in Tanzania and related agro-ecologies.

1. Introduction

Witchweeds (Striga species (spp.)), belonging to the family Orobanchaceae, are persistent weeds of grain crops in sub-Saharan Africa (SSA) and parts of Asia [1]. The obligate root hemiparasitic weeds cause yield losses of 20 to 100%, depending on Striga seed density, cultivar susceptibility, soil fertility status, and climatic conditions [2,3,4]. The genus comprises of more than 40 species worldwide, of which 11 species are considered parasitic on agricultural crops [5]. Of these Striga asiatica (L.) Kuntze, S. hermonthica (Del.) Benth, S. gesnerioides (Willd.) Vatke, S. forbesii (Benth.) and S. aspera cause devastating yield and quality losses to staple food crops in SSA [6,7]. Striga asiatica, S. hermonthica, S. forbesii and S. aspera parasitize cereal crops, while S. gesnerioides parasitize legumes, including wild and cultivated species [6,8]. Striga spp. inflict severe yield losses in maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench), pearl millet (Pennisetum glaucum (L.) R. Br.), rice (Oryza sativa L.), fìnger millet (Eleusine coracana L.) and cowpea (Vigna unguiculata L. Walp) [6,9].
Striga spp. affect about 100 million hectares of farmland cultivated by resource poor farmers in Africa. Consequently, it affects the livelihoods of over 300 million peoples who depends on the above major grain crops [5,10]. The most important cereal crop in Africa, maize, is exceptionally susceptible to Striga infestations. Low soil moisture caused by uneven and erratic rainfall, suboptimal soil nitrogen conditions and a lack of production inputs are common in marginal maize production areas of SSA, and these factors exacerbate the severity of losses [9,11,12]. An estimated 10 million tons of cereal grains are lost annually due to Striga damage in the SSA [13], which is worth an estimated at 7 billion USD in SSA [5,11]. In East Africa, monetary losses due to Striga damage was estimated at 335 million USD per year [14]. In Tanzania alone, monetary losses due to Striga damage are estimated to be 173 million USD [14]. Resource poor farmers are the most severely affected community in SSA, and Striga-induced losses increase the occurrence of food insecurity and abject poverty. This situation calls for a sustainable Striga control strategy that is compatible with current agronomic practices in the existing agro-ecosystem.
Conventional weed control strategies do not work well against Striga spp. because of its biology and the intimate physiological relationship with the host [15]. The weed produces large quantities of fine seeds that can remain viable in the soil for 20 years or more [16,17]. A single plant can produce up to 500,000 tiny, dust-like seeds, which mature at different times [18,19]. The effectiveness of Striga seed dispersal mechanism, which include migrating or grazing animals, wind, runoff during the rainy season and contaminated seeds aggravate the situation [20,21,22]. Thus, every year some seeds germinate, some revert to dormancy and some remain in the soil unconditioned, while more seeds are added from the current generation of plants, endlessly enriching the soil seed bank [5]. After germination, haustorial initiation occurs in response to specific chemical stimulants produced by a potential host [16,23]. The haustorium attaches, penetrates the host root, and establishes a connection with the host xylem just after germination to support Striga growth and survival [24]. Following attachment, the parasite remains subterranean for six to eight weeks, siphoning off water, nutrients, and inorganic solutes from the host xylem and/or phloem [24,25]. This is the most damaging stage, where Striga spp. exert a phytotoxic effect and impair photosynthesis within days of their attachment to the host roots [25,26,27].
Under the smallholder farming system, the current control practices used include hand hoe weeding and uprooting of Striga plants. However, these practices are laborious and time-consuming, and are seldom effective against Striga because the most severe damage leading to yield loss occurs before the Striga plants emerge above the ground [28,29]. A range of cultural practices such as manure application, rotating cereal crops with legumes, the use of trap crops that induce abortive germination of Striga seeds, shifting cultivation and long fallowing, are useful in reducing Striga damage and improving soil fertility [22,30,31]. However, they are not feasible for most smallholder farmers in SSA due to their need to use all agricultural lands intensively. Manure application remains the best Striga control option for smallholder farmers, but its application is limited by a limited supply of manure.
Chemical Striga control approach includes the use of methyl bromide, application of inorganic soil amendments such as fertilizers, ethylene, and post-emergence herbicides such as 2,4-D. Use of ethylene to promote suicidal germination followed by application of post-emergence herbicide such as 2,4-D to prevent weed reproduction has been widely and successfully used in the USA to control S. asiatica in maize production [32]. Fumigation of soils with methyl bromide was reported to be effective in killing Striga seeds in the soil [28]. Post-emergent herbicides are useful in preventing the build-up of Striga seeds in the soil but may not prevent damage prior to emergence [33]. However, these options are expensive and are not accessible to most smallholder farmers who operate in low-input agricultural production systems.
A relatively recent innovation has been the use of imazapyr applications to seeds of imazapyr-resistant maize (IR maize). This has resulted in significant increases in maize yields under S. hermonthica infestation [33,34,35]. However, the IR maize technology has one main drawback in that imazapyr is toxic to most other crops grown in Africa; hence it is not suitable in mixed cropping systems, which are common in SSA [4,36]. Therefore, control measures are needed that minimize the impact of Striga on crop losses, reduce the Striga seed banks in the soil, prevent new seed production and reduce the spread of Striga to uninfested fields [37]. Host resistance, combined with compatible agronomic practices, may solve some of the problems. Resistant cultivars can reduce both new Striga seed production as well as the Striga seed bank in infested soils in successive seasons [10,38].
Use of resistant varieties to control Striga species is the most effective, economical, and environmentally viable option for resource poor farmers [4,39]. Striga resistance refers to the ability of the host root to stimulate Striga seed germination but at the same time to prevent attachment of the Striga seedlings to its roots, or to kill the seedlings which attach to the roots. Tolerance refers to the ability of the host plant to withstand the effects of the parasitic plants that are already attached, regardless of their number with little yield loss [40,41]. Various studies have revealed that genes conferring resistance to S. hermonthica can been stacked in maize and these can intervene at several points in the pre-emergence stages of the Striga life cycle [38,42,43]. A significant breakthrough was attained by the International Institute of Tropical Agriculture (IITA) in developing maize genotypes with S. hermonthica resistance [38,43]. These genotypes could serve as valuable genetic resource for Striga resistance breeding programs in SSA, including Tanzania.
Striga resistance in maize is expressed in several ways, including low stimulation of Striga seed germination [16,44,45], low haustorial induction [16], avoidance through root architecture (fewer thin branches) [46], escape by early maturity [47], host resistance to Striga attachment [46], and failure to support attached parasites (incompatibility) [16,46,48]. However, the levels of Striga host resistance that have been attained so far in maize are not adequate to counteract high levels of Striga infestation. The current Striga-resistant/tolerant genotypes allow for the flowering and seed set of Striga plants, thus enriching the Striga seedbank in the soil [49,50,51]. Thus, the use of Striga-resistant genotypes combined with a biological control agent and farmers’ current agronomic practices may constitute a substantially more effective Striga control strategy.
Biological control denotes the deliberate use of living organisms to suppress, reduce, or eradicate a pest population [52]. The technique is less expensive and more environmentally friendly than chemical control options [53,54]. Prior research has shown that the presence of mycoherbicides in the rhizosphere of susceptible crops reduces the levels of Striga parasitism on the host plant [10,55,56]. Pathogenic isolates of Fusarium oxysporum Schlecht. emend. Synder and Hans f. sp. strigae (FOS) are reported to be efficient in controlling S. asiatica and S. hermonthica infestation in maize and sorghum [7,57]. The biocontrol agent is most effective when combined with Striga-resistant genotypes and other control measures [7,10]. It is reported that the integrated effects of Striga-resistant maize genotypes and FOS reduced Striga emergence by over 90% [57]. Gebretsadik et al. [7] reported up to a 92% reduction in Striga emergence counts when a FOS treatment was applied to Striga-resistant sorghum varieties. Beed et al. [55] reported a reduction of S. hermonthica emergence by 98% and an increase in sorghum yield by 26% following FOS application. FOS can endophytically colonize the root system of the maize host, and from this base, can attack Striga spp. at all growth stages including seeds, seedlings, and flowering shoots, thus affecting the target prior to seed set and crop yield loss, thereby reducing the Striga seedbank [55,58]. Fungi are preferred to other microorganisms as bio-herbicides because they are usually host-specific, attacking only Striga spp. [15,59,60]. Additionally, fungi are highly aggressive, easy to mass produce and are diverse in terms of number of strains available [7,61]. FOS compatible genotypes support no or few Striga plants and produce relatively high yields under Striga infestation. Thus, the use of host plant resistance combined with FOS and sound cultural practices is a viable strategy for enhancing crop yields in Striga infested fields. The development of host plant resistance through breeding is a fundamental component of a sustainable integrated Striga management strategy to minimize yield losses in farmers’ fields. A successful maize breeding program depends mainly on the available genetic variation within the germplasm resources [62,63]. Therefore, the aim of the present study was to screen genetically diverse maize genotypes with farmer preferred traits from a range of distinct sources, and to screen these genotypes for resistance to S. asiatica and S. hermonthica, and for FOS compatibility, aiming to develop an integrated Striga control program in Tanzania.

2. Materials and Methods

2.1. Germplasm

The study used 56 genetically diverse maize genotypes consisting of 34 landraces acquired from the National Plant Genetic Resources Centre (NPGRC), Tanzania, 18 improved Open Pollinated Varieties (OPVs) from the International Institute of Tropical Agriculture (IITA), Nigeria, and four OPVs from Tanzania Agricultural Research Institute (TARI), Tanzania. The IITA collection included 17 Striga-resistant genotypes and one Striga susceptible genotype which were used as checks. The details of the studied genotypes are presented in Table 1.

2.2. Collection of Striga Seeds

Striga seeds were collected from maize and sorghum fields infested with either of the two Striga species or both in the 2016/2017 growing season. The seed of S. asiatica was collected at the TARI—Hombolo Research Centre, Dodoma region and the TARI Tumbi Research Centre, Tabora region, while the seed of S. hermonthica was collected in the Mbutu and Igogo wards, Igunga district, Tabora region. Striga seeds from both species were separately processed, packed, labelled, and stored in the Soil Science Laboratory of TARI Tumbi for further use.

2.3. Collection and Inoculation of Fusarium Oxysporum f. sp. Strigae (FOS)

A virulent strain of FOS was used as the biocontrol agent. This was initially isolated from severely diseased Striga plants in sorghum fields in north-eastern Ethiopia [7]. The host specificity and pathogenicity of the FOS isolate on Striga spp. have been previously described by Gebretsadik et al. [7]. The Phytomedicine Department of Humboldt University in Berlin, Germany confirmed the taxonomic identification of FOS [7]. Pure FOS spores are produced and preserved by Plant Health Products (Pty) Ltd., KwaZulu-Natal, South Africa [7]. FOS in a dry powder formulation (supplied by Dr. M.J. Morris of Plant Health Products (Pty) Ltd.) was used to coat the maize seeds before sowing. The 26.8 mg of FOS inoculum was applied to the whole surface of the seed. The specialized hairy structures present at the tip of maize seeds (the pedicel) bind enough FOS inoculum to be effective, without the need for a sticker.

2.4. Experimental Procedure

The experiment was established during the 2017/2018 growing season in a screen house facility at TARI-Tumbi Research Centre situated in the Tabora Municipality, western Tanzania. The center is located at 5°03′ S Latitude and 32°41′ E Longitude with an altitude of 1190 m above sea level. The experiment was established using a split-plot design, with a FOS treatment being the main plot factor and maize genotypes as the subplot factor. The genotypes were sown in a screenhouse using polyethylene plastic pots (250 mm diameter and 350 mm height) filled with a growing medium consisting of topsoil and sandy soil mixed at a ratio of 6:3. A total of 1680 pots were filled with the growing medium and divided into sets of 336, and two equal sets of 672 pots. The set of 336 pots was not infested with Striga seeds nor treated with FOS (the untreated, uninoculated control). The first set of 672 pots was infested with 30 mg of one-year old S. asiatica (Sa) seeds uniformly distributed at a depth of 30 mm in the growing medium. The second set of 672 pots was infested with 30 mg of one-year old S. hermonthica (Sh) seeds. After 14 days of Striga seed preconditioning, maize seeds were sown in the following order: half of the pots (336) assigned either to Sa or Sh were planted with 2 seeds of the maize genotypes coated with 26.8 mg of FOS powder. The seeds planted in the other 336 pots infested with Sa or Sh were not inoculated with FOS. After emergence, maize plants were thinned to one seedling per pot. Each experimental plot consisted of 2 pots, and these were replicated three times for each treatment. Other agronomic practices used were irrigation, soil fertilization, and weeding. Weeds other than the two Striga species were uprooted manually.

2.5. Data Collection

Data were collected based on maize agronomic characters and Striga resistance parameters. The following data were recorded on maize plants: days to 50% anthesis (50% AD) was recorded as the number of days from sowing to when 50% of the plants in a plot shed pollen. The days to 50% silking (50% SD) was recorded as the number of days from planting to when 50% of the plants in a plot produced silks. Anthesis-silking-interval (ASI) was determined as the difference between days to 50% silking and 50% anthesis. The days to 75% maturity (DM) were recorded as the number of days from planting to when 75% of the plants reached physiological maturity [64]. Plant height (PH) was measured from the base of the plant (expressed in cm) to the top of the first tassel branch. Ear height (EH) was measured (cm) from the ground level to the node bearing the uppermost ear. Grain yield/plant (GY) was determined as the weight (g), of the grain from the ears of individual plants after shelling, converted to a constant moisture of 12.5%. Hundred-grain weight was recorded based on a weight (g) of 100 kernels at field moisture content and converted to a constant moisture of 12.5%. The above-ground biomass (AGB) was determined by weighing (g/plant) the above-ground plant parts which included: leaves, stems, and ears. Individual maize plants were cut at the base of the stem.
The following Striga parameters were recorded: Striga emergence counts were recorded at 8 weeks after planting (SEC8) and 10 weeks after planting (SEC10) as the number of emerged Striga plants per genotype. A rating of host plant damage was made at 8 and 10 weeks after planting, denoted as SDR8 and SDR10, using a scale of 1 to 9 as described by Kim [40]. A scale of 1 = normal maize growth with no visible symptoms and 9 = virtually all area scorched, two thirds or more reduction in height, most stems collapsing, no useful ear formed, miniature or no tassel, no pollen production, and dead or nearly dead plant.

2.6. Data Analysis

Maize agronomic and Striga parameters were organized in an Excel spreadsheet and subjected to analysis of variance (ANOVA) using the split-plot procedure in GENSTAT 18th Edition [65]. Significance tests were carried out at the 5% probability level. Data on the Striga emergence counts were square root transformed (y = √(x + 0.5)) before analysis to meet normalization assumptions. Mean separation was performed using Fisher’s least significant difference (LSD) test at the 5% probability level. Correlation analysis was conducted separately between FOS-treated and untreated maize genotypes under both Sh and Sa infestation to discern the relationship among maize agronomic traits and Striga parameters. Furthermore, maize agronomic data and Striga parameters from FOS-treated and untreated genotypes were subjected to principal component analysis (PCA) using the mean values of the 56 maize genotypes using the Statistical Package for Social Science Studies (SPSS) Version 24.0 (SPSS, 2017) [66], to group and identify important traits under Striga infestation, with and without FOS treatment.

3. Results

3.1. Effects of FOS on Maize Genotypes and Striga Hermonthica Parameters

Genotypes exhibited highly significant (p < 0.001) differences for all agronomic traits studied under Sh infestation, with and without FOS treatments (Table 2). Furthermore, the test genotypes differed significantly (p < 0.001) for all S. hermonthica parameters studied (Table 2). The interaction between maize genotypes and FOS was highly significant (p < 0.01) for all the maize traits assessed except hundred kernel weight. The interaction between maize genotypes and FOS showed highly significant (p < 0.001) differences for S. hermonthica resistance parameters such as Sh emergence count at eight weeks after planting (ShEC8) and ten weeks after planting (ShEC10), except for the Sh damage rating at both ShEC8 and ShEC10 (Table 2).

3.2. Mean Performance of Maize Genotypes under S. Hermonthica, with and without FOS Treatments

The mean performance of the test genotypes under Sh infestation, with and without FOS treatments, are summarized in Table 3, together with the control (without both Sh and FOS) are presented in Table 4. The mean anthesis-silking-interval under Sh infestation without FOS treatment ranged from 0.33 (genotype TZA4165) to 6 days (TZA3952) with an overall mean of 2.16 days. The genotypes anthesis-silking-interval under Sh infestation with FOS treatment ranged from 1.33 (JL16) to 7.67 days (TZA1782) with a mean of 2.40 days (Table 3) and that of the control treatment varied from 1.67 to 7.33 with a mean of 2.08 days (Table 4). The results show an increase of 15% anthesis-silking-interval for FOS-treated genotypes and 4% for untreated genotypes under Sh infestation. The mean grain yield in the control, FOS-treated, and untreated genotypes under Sh infestation was 93.86, 80.78 and 75.90 g/plant, respectively (Table 3 and Table 4). Grain yield varied from 42.85 (TZA3181) to 146.64 g/plant (TZA3827) under the control treatment, from 45.59 g/plant (TZA3952) to 128.11 g/plant (TZA3827) in FOS-treated genotypes, and from 38.47 g/plant (TZA3964) to 119.60 g/plant (TZA2263) for untreated genotypes under Sh infestation. FOS-treated genotypes had higher grain yields than untreated genotypes under Sh infestation. The mean value showed a grain yield reduction of 19.13% in untreated genotypes compared with to a loss of 13.94% in FOS-treated genotypes, relative to the control. Some FOS-treated genotypes recorded higher percent yield increases than the control treatment: TZA1782 (19.07%), TZA3181 (14.88%), JL21 (14.73%), JL02 (9.16%), JL25 (10.4%), TZA3417 (11.72%), TZA3964 (12.20%) and TZA604 (9.11%) (Table 3 and Table 4). The mean fresh biomass ranged from 88.30 g/plant (TZA3502) to 354 g/plant (TZA1780) in the control, 72.5 g/plant (TZA3502) to 335 g/plant (TZA4203) in FOS-treated genotypes, and 75.80 (TZA3502) to 289.20 g/plant (TZA1780) under Sh infestation without FOS treatment. The mean fresh biomass was 190.6 g/plant in the control, 152.7 in FOS-treated genotypes and 143.5 g/plant in untreated genotypes under Sh infestation. The results show a reduction of fresh biomass by 24.7% in Sh infested genotypes without FOS treatment and 20% loss for FOS-treated genotypes compared to the control. The application of FOS significantly reduced the number of emerged Sh plants compared to the untreated genotypes. Under Sh infestation without FOS application, the following genotypes had the highest number of emerged Sh plants at ten weeks after planting: TZA4165 (9.37 Sh plants), TZA1771 (17.11), TZA4000 (10.99), TZA615 (10.62), JL06 (11.86), and TZA3570 (8.00). When the same genotypes were treated with FOS, the mean Sh emergence count dropped to 0.87, 5.35, 3.68, 2.19, 6.66 and 2.65, respectively (Table 3). Significant percent reductions in the number of emerged Sh plants were recorded at 90.72% (for genotype TZA4165), 68.73% (TZA1771), 66.52% (TZA4000), 79.38% (TZA615), 43.84% (JL06), and 69.56% (TZA3570), in FOS-treated genotypes. Although most of the FOS-treated genotypes stimulated fewer Sh plants to emerge at both eight and ten weeks after planting than untreated genotypes, some of the FOS-treated genotypes showed an increased number of emerged Sh plants compared to the untreated genotypes. The following FOS-treated genotypes showed an increase in the number of Sh emergence ten weeks after planting compared to untreated genotypes: TZA3181 (9.32 Sh plants), TZA599 (8.79), JL01 (8.69), TZA604 (6.79), TZA1780 (4.5), JL20 (3.46) and JL09 (3.36) (Table 3). The Sh damage rating score 10 weeks after planting, with and without FOS treatment, ranged from 1.00 (TZA4320) to 2.33 (JL25, TZA599, TZA604) and did not differ significantly. The mean Sh damage rating score, with and without FOS treatment, at 10 weeks after planting was 1.26 and 1.36, respectively. Based on Sh emergence count, FOS compatibility, grain yield and the presence of farmer preferred traits, the following genotypes were selected for Striga breeding purposes; TZA4205, TZA1775, TZA3417, TZA4203, TZA1780, TZA4010, TZA4165, TZA4016, TZA2263, TZA3827, JL24, JL22, JL01, JL05, JL08, JL09, JL13, JL15, JL16, JL17, JL18, JL19, and JL20. These genotypes are denoted in bold face text in Table 3.

3.3. Effects of FOS on Maize Genotypes and Striga Asiatica Parameters

The ANOVA revealed highly significant (p < 0.001) differences for all maize agronomic traits studied under Sa infestation, with and without FOS treatment (Table 5). FOS treatment on maize genotypes significantly (p < 0.001) affected the test genotypes and Sa resistance traits. The interactions between maize genotypes and FOS were highly significant (p < 0.01) for all the maize traits studied except for hundred kernel weight. Likewise, the interaction mean squares between maize genotypes and FOS exhibited significant (p < 0.001) differences for the Sa emergence counts at 8 and 10 weeks after sowing (Table 5).

3.4. Mean Performance of Maize Genotypes under S. Asiatica, with and without FOS

Table 6 summarizes the mean performance of the maize genotypes evaluated under Sa infestation, with and without FOS treatment. The mean Sa emergence count 8 weeks after sowing under Sa infestation, with and without FOS treatment, ranged from 0.0 Sa plants (for the genotype TZA3417) to 45.90 Sa plants (TZA4064), and 0.5 (TZA4320) to 45.52 Sa plants (TZA599), respectively. The Sa emergence count 10 weeks after sowing, with and without FOS treatment, ranged from 1.42 Sa plants for the genotype TZA3417 to 58.07 plants (TZA4064), and 1.42 (TZA4320) to 59.52 (TZA599). Most of the FOS-treated genotypes under Sa infestation showed a remarkable reduction in the number of emerged Sa plants. Likewise, Sa damage rating at 8 and 10 weeks after sowing was significantly reduced in FOS-treated genotypes relative to untreated counterparts. The following genotypes showed over 50% reduction on the number of emerged Sa counts when treated with FOS compared to untreated ones under Sa infestation, 10 weeks after sowing: TZA3417 (90.7%), TZA3502 (76.65%), TZA1784 (72.5%), TZA4016 (65.4%), TZA3181 (63.44%), JL17 (60.94%), JL22 (57.75%), and TZA2881 (50.25%) (Table 6). However, some FOS-treated genotypes under Sa infestation supported more Sa plants than untreated genotypes 10 weeks after planting. See for example, TZA3952 (12.47), TZA3570 (27.42), TZA3964 (16.91), JL01 (10.45), TZA604 (25.52), TZA4064 (32.54), TZA1782 (24.19), TZA1775 (22.38), and TZA2761 (16.92). These counts can be converted to percentages of Sa plants supported: 494.84% (genotype TZA3952), 427.77% (TZA3570), 383.45% (TZA3964), 211.73% (TZA1775), 177.12% (JL01), 157.24% (TZA604), 127.45% (TZA4064), TZA1782 (114.70%) and TZA2761 (107.84%) 10 weeks after planting, under Sa infestation with FOS treatment.
Under Sa infestation, FOS-treated genotypes had higher grain yields than untreated genotypes (Table 6). Mean grain yields in the controls, FOS-treated, and untreated genotypes with Sa infestation were 93.86, 77.07 and 73.80 g/plant, respectively. On average, FOS-treated genotypes under Sa infestation suffered a grain yield reduction of 18%, while untreated genotypes had a 21.4% grain yield loss, compared to the control treatment (Table 4 and Table 6). Grain yield performance of some FOS-treated genotypes under Sa infestation surpassed that of the control treatment, including TZA1780 (31.44%), TZA3181 (28.47%), JL21 (11.48%), TZA1782 (10.27%), TZA604 (8.81%), TZA3964 (6.71%) and TZA4165 (6.04%). Conversely, grain yield for TZA1780 under Sa without FOS treatment exceeded that of the control treatment by 7.18%. Grain yield for the genotypes JL03 and JL13 under Sa infestation with FOS treatment are not substantially different from that of the control (Table 4 and Table 6). The mean fresh biomass was 190.6 g/plant in the control, 150.9 g/plant in FOS-treated and 143.6 g/plant in untreated genotypes under Sa infestation. The mean above-ground biomass under Sa infestation, with and without FOS application, varied from 60 (TZA3502) to 350 g/plant (TZA1780), and 65 (TZA3502) to 318.30 (TZA1780) g/plant, respectively. The mean plant height was 294.27 cm in the control, 279.56 cm in FOS-treated and 272.64 cm in untreated genotypes, respectively. Plant height was reduced by 5% for FOS-treated genotypes and 7.4% for untreated genotypes, under Sa infestation compared to the control. Based on the number of emerged Sa plants, FOS compatibility and grain quality characteristics, the following genotypes were selected for Striga resistance breeding purposes: TZA4205, TZA1775, TZA3417, TZA4203, TZA1780, TZA4010, TZA4165, TZA4016, TZA2263, TZA3827, JL24, JL22, JL01, JL05, JL08, JL09, JL13, JL15, JL16, JL17, JL18, JL19, and JL20.

3.5. Association between Maize Agronomic Traits and Striga Parameters Assessed under Striga Hermonthica Infestation, with and without FOS

Coefficients of correlation explaining the degree of association for the studied traits among 56 maize genotypes evaluated under Sh infestation, with and without FOS, are summarized in Table 7. For FOS-treated genotypes, grain yield exhibited significant (p < 0.05) and negative correlation with the anthesis-silking-interval (r = −0.17) and ear height (r = −0.19). Above-ground biomass was significantly (p < 0.01) correlated with days to 50% anthesis (r = 0.54), days to 50% silking (r = 0.51) and days to maturity (r = 66). In addition, days to 50% anthesis had significant (p < 0.05) correlations for all Sh parameters studied under FOS treatment. Likewise, the anthesis-silking-interval showed significant (p < 0.05) correlations with Sh emergence counts at 8 (r = 0.20) and 10 weeks after sowing (r = 0.18). Striga traits such as ShEC8, SheC10, ShDR8 and ShDR10 were significant (p < 0.05) and positively correlated among each other under Sh infestation with FOS treatment. Furthermore, under Sh infestation without FOS treatment, grain yield was significantly (p < 0.05) and negatively correlated with hundred kernel weight (r = −0.17), days to 50% silking (r = −0.22), anthesis-silking-interval (r = −0.35) and plant height (r = −0.24). Additionally, days to 50% anthesis exhibited significant (p < 0.01) correlations with days to 50% silking (r = 0.93), ear height (r = 0.95) and days to maturity (r = 0.48). Moreover, days to 50% anthesis showed significant (p < 0.05) correlations with Sh emergence counts at eight weeks (r = 0.18) and ten weeks (r = 0.25). Days to 50% anthesis was significantly (p < 0.05) correlated with Sh damage ratings at eight (r = 0.19) and ten (r = 0.20) weeks after sowing. All Striga parameters under Sh infestation without FOS treatments are highly correlated.

3.6. Association between Maize Agronomic Traits and Striga Parameters Assessed under Striga Asiatica Infestation, with and without FOS Treatment

Pearson correlation coefficients describing the relationship of the studied traits among 56 maize genotypes assessed under Sa infestation, with and without FOS treatments, are summarized in Table 8. Grain yield showed significant (p < 0.01) and negative correlations with plant height (r = −0.23), ear height (r = −0.20) and hundred kernel weight (r = −0.22) under FOS treatment. Furthermore, grain yield exhibited a significant (p < 0.01) positive correlation with days to maturity (r = 0.23). For FOS-treated genotypes, hundred kernel weight was significantly (p < 0.01) correlated with plant height (r = 0.38), ear height (r = 0.3) and above-ground biomass (r = 0.23). Additionally, hundred kernel weight had significant (p < 0.05) correlations with Sa emergence counts at eight (r = 0.19) and ten (r = 0.21) weeks after sowing. Hundred kernel weight was significantly (p < 0.05) correlated with Sa damage rating at eight (r = 0.18) and ten (r = 0.17) weeks after sowing. Likewise, above-ground biomass, exhibited significant (p < 0.01) correlations with days to maturity (r = 0.74), days to 50% silking (r = 0.52), days to 50% anthesis (r = 0.49), and Sa emergence counts eight (r = 0.25), and ten (r = 0.23) weeks after sowing. Above-ground biomass had significant (p < 0.05) correlations with Sa damage ratings at eight (r = 0.23) and ten (r = 0.18) weeks after sowing. Under FOS treatment, all the Sa parameters exhibited strong and significant (p < 0.05) correlations among each other (r > 0.7) Table 8. When genotypes were infested with Sa without FOS treatment, grain yield showed significant (p < 0.01) and negative correlations with days to 50% silking (r = −0.23), anthesis-silking interval (−0.26), plant height (r = −0.31) and ear height (r = −0.29). Furthermore, above-ground biomass exhibited significant (p < 0.05) correlations with days to maturity (r = 0.73), ear height (r = 0.52), days to 50% silking (r =0.51) and days to 50% anthesis (r = 0.54). In addition, above-ground biomass without FOS treatment revealed significant (p < 0.05) correlations with Sa emergence count ten (r = 0.16) weeks after sowing and the Sa damage rating ten (r = 0.18) weeks after sowing. Furthermore, for untreated maize genotypes, days to 50% anthesis had significant (p < 0.05) correlations with Sa emergence counts eight (r = 0.18) and ten (r = 0.18) weeks after sowing. Days to 50% anthesis also showed significant correlations with Sa damage ratings eight (r = 0.16) and ten (r = 0.26) weeks after sowing without FOS treatment.

3.7. Principal Components Analysis (PCA) of the Maize Agronomic Traits and S. hermonthica Parameters under Sh infestation, with and without FOS Treatment

A summary for the rotated component matrix of the PCA, following Varimax rotation with Kaiser Normalization is presented in Table 9 for maize agronomic traits under Sh infestation, with and without FOS treatment. Three principal components were important in allocating traits for both FOS-treated and untreated maize genotypes. From the untreated maize genotypes evaluated under Sh infestation, the first three principal components (PCs) with eigen values greater than 1 accounted for 75.47% of the total variation (Table 9). The first principal component (PC1) was dominated by four Sh resistance parameters (ShEC8, ShEC10, ShDR8, ShDR10) and explained 28.06% of the total variance relating to Striga infestation. The second principal component (PC2) was highly influenced by four maize agronomic traits (AGB, DM, AD and SD) with high positive loadings explaining 23.77% of the total variation. The third principal component (PC3) was mainly associated with three maize traits (PH, EH and ASI) with high positive loadings, and GYD with a high negative loading, contributing 23.64% of the total variation (Table 9). Likewise, in the FOS-treated genotypes under Sh infestation, three principal components were significant, and explained 74.19% of the total variance in the original data set (Table 9). Sh parameters (ShEC8, ShEC10, ShDR8, ShDR10) were the main contributors of the first principal component (PC1), accounting for 28.9% of the total variation. The second principal component (PC2) was governed by traits such as AGB, AD, DM, explaining 23.85% of the total variance, whereas maize traits such as PH, EH and ASI had high positive loadings into the third principal component (PC3), describing 21.43% of the total variance (Table 9).

3.8. Principal Components Analysis Based on Maize Traits and S. Asiatica Resistance Traits under Sa Infestation with and without FOS Treatment

Table 10 summarizes the rotated component matrix of the PCA, following Varimax rotation with Kaiser Normalization, for maize agronomic traits under Sh infestation, with and without FOS treatment. From the untreated genotypes, under Sa infestation, three principal components were important, explaining 77.47% of the total variance in the original data set. Traits contributing strongly to the first principal component (PC1) were SaEC8 (0.97), SaEC10 (0.97), SaDR8 (0.95), and SaDR10 (0.91), respectively, accounting for 29.61% of the total variance. The second principal component was mainly influenced by AGB (0.92), DM (0.89), AD (0.80) and SD (0.79), respectively, explaining 26.44% of the total variance. Likewise, the third principal component (PC3) was dominated by three maize traits PH (0.88), GYD (−0.79) and EH (0.76), accounting for 21.42% of the total variance. Furthermore, in FOS-treated maize genotypes under Sa infestation, four principal components were important, explaining 82.08% of the total variation. Four Sa resistance traits, SaEC8, SaEC10, SaDR8, and SaDR10, had high positive loadings into PC1, contributing 28.91% to the total variance. The second principal component in FOS-treated genotypes under Sa infestation was mainly contributed to by maize traits such as AD, SD, DM, and AGB, which accounted for 25.72% of the total variance. Likewise, PC3 comprised of PH and EH, which had high positive loadings and GYD with a negative loading, accounting for 16.29% of the total variance. The fourth principal component was influenced by ASI, explaining 11.16% of the total variation in the original data set.

4. Discussion

The present study identified highly significant differences for all maize agronomic traits and Striga parameters studied under both Sh and Sa infestation, with and without FOS treatments (Table 2 and Table 5). This suggests that the test genotypes possess adequate genetic variability from which selection for Sh and Sa resistance breeding could be done. The higher the genetic variation present among the test genotypes, the greater the probability of success for developing new superior Striga-resistant varieties. An effective maize breeding program depends primarily on the available genetic variation within and between the genetic resources [62,63].
The application of the FOS treatment to the maize genotypes significantly (p < 0.001) affected the test genotypes and Striga parameters. The high variability behavior of the test genotypes for all the Striga parameters studied, with and without FOS treatment, could be ascribed to the genetic constitutions and FOS compatibility. Striga emergence count, Striga damage rating, and grain yield under Striga infestation are significant traits for describing the level of resistance of genotypes to Striga infestation [67,68]. The interaction between maize genotypes and FOS was significant (p < 0.05) for all the maize traits studied except for hundred kernel weight. Likewise, the interaction mean squares between maize genotypes and FOS exhibited significant (p < 0.001) difference for Sh and Sa emergence counts at eight and ten weeks after sowing (Table 2 and Table 5). This measures the compatibility of the test genotypes with the biocontrol agent, FOS, and thus selections could be made, based on the genotypes individual Striga resistance and their FOS compatibility, under Sh and Sa infestation. Significant interactions between FOS and genotypes suggests the presence of synergistic effects between them for the management of Striga spp. Compatibility between test genotypes and FOS allows the biocontrol agent to colonize the root rhizospheres of the host genotypes, and subsequently to suppress Striga growth and establishment [10,56,57], reducing Striga parasitism to the host plant roots and improving grain yield [7,10,56]. In the present study, FOS-treated genotypes recorded higher grain yields than the untreated genotypes under both Sh and Sa infestation (Table 3 and Table 6). The mean grain yield for FOS-treated genotypes under Sh infestation increased by 5.12 g/plant yield relative to the untreated treatment, amounting to 6.80% (Table 3). Likewise, under Sa infestation, FOS-treated genotypes had a mean yield increase of 4.5% (Table 6). These findings agree with those reported by Shayanowako et al. [56] and Venne et al. [57], when studying the effect of FOS on maize genotypes under Sh and Sa infestation, respectively.
Grain yield performance of some FOS-treated genotypes under both Sh and Sa infestation surpassed that of the control treatment. These included TZA3181 (28.47%), TZA1782 (19.07%), JL21 (14.73%), TZA3964 (12.2%), TZA604 (9.11%) and JL25 (10.40%) (Table 3 and Table 6). Similar findings have been reported by [10] when screening sorghum genotypes for FOS compatibility under Sh and Sa infestation. This confirms the effectiveness of FOS in enhancing the performance of the test genotypes assessed under Sh and Sa infestation. Furthermore, the present study recorded higher fresh biomass for FOS-treated genotypes compared to untreated genotypes under both Sh and Sa infestation (Table 3 and Table 6). Under Sh infestation the following FOS-treated genotypes recorded higher fresh biomass than the uninfested and untreated control treatment: TZA3827 (33.3 g/plant), JL08 (28.3 g/plant), JL05 (31 g/plant) and TZA4203 (26 g/plant) (Table 3 and Table 4). Likewise, under Sa infestation, the following FOS-treated genotypes had fresh biomass that surpassed that of the control (uninfested and untreated): TZA3827 (32.5 g/plant), TZA599(30 g/plant) and JL24 (21 g/plant) (Table 4 and Table 6). This confirms the effectiveness of FOS in suppressing the Striga spp. and its ability to stimulate plant growth in compatible genotypes. Thus, water, nutrients, and inorganic solutes from the host xylem could be translocated towards the upper plant parts, improving plant vigor, biomass, and consequently grain yield. Studies done earlier on the efficacy of FOS on sorghum genotypes recorded higher fresh biomass on FOS-treated genotypes than untreated control under Striga spp. infestation [7,10]. Furthermore, FOS-treated genotypes recorded significantly lower numbers of emerged Striga plants at both eight and ten weeks after sowing. Under Sh infestation, FOS-treated genotypes supported reduced Striga numbers by up to 90.72% (TZA4165) at ten weeks after sowing (Table 3). Likewise, under Sa infestation, FOS was able to reduce the number of emerged Sa plants up to 90.7% (TZA3417) ten weeks after sowing (Table 5). This confirmed the ability of the mycoherbicide to attack Striga spp. at different growth stages before emergence and flowering. The reduction of Striga number in FOS-treated maize genotypes was reported earlier in field and pot experiments [56,57]. FOS reduces Striga spp. though complete digestion of Sh and Sa seedlings inside the host and clogging of vessels of emerged Striga plants by hyphae, causing wilting and subsequent death of Striga plants [69]. The present study noted some cases where there were few or zero emerged Striga plants, as well as wilting of emerged Striga plants in some of FOS-treated pots, suggesting the efficacy of FOS in infecting Striga seeds, seedlings, and shoots. Comparable observations have been reported before in field and pot experiments involving maize and sorghum treated with FOS [10,70]. Some FOS-treated genotypes (TZA604, TZA3952, TZA4064 and JL01) under both Sh and Sa infestation supported an increased number of emerged Striga plants at eight and ten weeks after planting, suggesting FOS incompatibility. Some Striga-resistant genotypes excrete exudates that are inhibitory to fungal growth, rendering them FOS incompatible [57]. Conversely, FOS compatible maize genotypes release exudates that activate virulence genes of the Striga mycoherbicide to efficiently suppress the parasite [56]. FOS is highly host-specific, and it may be more compatible with some maize genotypes than others [60,71,72].
In the present study, secondary traits such days to 50% anthesis, days to 50% silking, anthesis-silking-interval, plant height, and ear height under Sh and Sa infestation, revealed significant and positive correlations with Striga parameters after FOS treatment (Table 7 and Table 8). This suggested that selection of one trait may simultaneously improve the other under FOS treatment. It has been reported that secondary traits play a significant role in the selection for improved grain yield under Striga infestation [73]. The studied Striga parameters of Striga emergence counts at eight and ten weeks after planting, and Striga damage rating at eight and ten weeks after planting were highly significant and positively correlated among each other. This suggests that selection for one trait may improve the performance of another simultaneously. Therefore, either of these parameters could serve as a selection criterion for the evaluation of genotypes for Striga resistance [41].
Principal component analysis performed on the mean values of each trait, identified the most important traits that accounted for most of the variance in the data set (Table 8 and Table 9). Striga emergence count and Striga host damage rating at eight and ten weeks after sowing were the most significant traits, which accounted for the highest proportion of the variance in the data set. These traits were loaded in the first principal component (PC1) under both Sh and Sa infestation, with and without FOS treatment. Comparable results have been reported earlier in sorghum study involving FOS treatment [7]. Maize traits such as above-ground biomass, days to 50% anthesis, and days to maturity formed the second-best linear combinations of traits and were loaded in the second principal component (PC2) under both Sh and Sa infestation with and without FOS application. The traits grouped by the principal components, reflected significant relationships with Striga parameters under the Pearson correlation matrix, while Striga traits had strong positive correlations with each other. This suggests their usefulness in discriminating between the genotypes and should be considered during evaluation for Striga resistance [56]. The strong negative loading found on grain yield per plant was expected because as Striga thrives, it causes damage to the host, thereby reducing grain yield.

5. Conclusions

The application of FOS to maize genotypes under both S. hermonthica and S. asiatica infestation enhanced the resistance of the test genotypes to Striga and significantly reduced the number of emerged Striga plants and the levels of Striga-induced host damage, and subsequently improved grain yield of many test genotypes, compared to the untreated ones. The study demonstrated the value of combining host plant resistance, farmers compatible cultural practices and FOS for integrated Striga control in maize in Tanzania. Additionally, the study identified 23 genotypes with variable resistance, high grain yield, farmers preferred traits and FOS compatible for a Striga resistance breeding program in Tanzania. Development and deployment of Striga-resistant and FOS compatible crop genotypes is a fundamental component of an integrated Striga management strategy in Striga infested agricultural lands. However, the identified maize genotypes need to be evaluated in multiple field conditions after FOS treatment to substantiate the findings recorded in the screen house.

Author Contributions

Conceptualization, J.L., and H.S.; Methodology, J.L., H.S., and M.D.L.; Formal analysis, J.L., A.I.T.S., and A.A.M.; Implementation of experiments, Data collection and writing—original draft preparation, J.L.; Writing—review and editing, J.L., H.S., M.D.L., A.A.M., and A.I.T.S.; Funding acquisition, H.S., and M.D.L. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Alliance for Green Revolution in Africa (AGRA) through the African Centre for Crop Improvement (PASS030), University of KwaZulu-Natal.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

All data generated or analyzed during this study are included in the present article.

Acknowledgments

The Alliance for a Green Revolution in Africa (AGRA) is gratefully acknowledged for financing this study through the African Centre for Crop Improvement (ACCI) at the University of KwaZulu Natal (UKZN); the Tanzania Agricultural Research Institute—is highly thanked for providing screen house, office space, some germplasm and transport. The International Institute of Tropical Agriculture (IITA), National Plant Genetic Resources Centre for Tanzania (NPGRC) are greatly appreciated for germplasm supply. The authors are thankful to M.J. Morris of Plant Health Products (Pty) Ltd. for supplying FOS. Many thanks are due to the Permanent Secretary, Ministry of Agriculture, Government of Tanzania, for granting study leave to the first author.

Conflicts of Interest

The authors declare no conflict of interest.

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Table
Table 1. List and source of maize accessions used for the study.
Table 1. List and source of maize accessions used for the study.
S/NoGermplasm CodeName/Designation/PedigreeDescriptionStriga Resistance StatusSource/Origin
1TZA599IpukileLandraceUnknownNPGRC/Tanzania
2TZA604IpukeleLandraceUnknownNPGRC/Tanzania
3TZA615MahindiLandraceUnknownNPGRC/Tanzania
4TZA687NyamulaLandraceUnknownNPGRC/Tanzania
5TZA1771KatumaniLandraceUnknownNPGRC/Tanzania
6TZA1775MahindiLandraceUnknownNPGRC/Tanzania
7TZA1780MahindiLandraceUnknownNPGRC/Tanzania
8TZA1782MahindiLandraceUnknownNPGRC/Tanzania
9TZA1784MahindiLandraceUnknownNPGRC/Tanzania
10TZA2263MahindiLandraceUnknownNPGRC/Tanzania
11TZA2749MahindiLandraceUnknownNPGRC/Tanzania
12TZA2761MahindiLandraceUnknownNPGRC/Tanzania
13TZA2881MahindiLandraceUnknownNPGRC/Tanzania
14TZA3095LandraceLandraceUnknownNPGRC/Tanzania
15TZA3181UruwingaLandraceUnknownNPGRC/Tanzania
16TZA3417MahindiLandraceUnknownNPGRC/Tanzania
17TZA3502KatumbiliLandraceUnknownNPGRC/Tanzania
18TZA3561MahindiLandraceUnknownNPGRC/Tanzania
19TZA3570OlomanLandraceUnknownNPGRC/Tanzania
20TZA3614MagerezaLandraceUnknownNPGRC/Tanzania
21TZA3827MahindiLandraceUnknownNPGRC/Tanzania
22TZA3942ZimbabweLandraceUnknownNPGRC/Tanzania
23TZA3951MwarabuLandraceUnknownNPGRC/Tanzania
24TZA3952MwarabuLandraceUnknownNPGRC/Tanzania
25TZA3964AmakuriaLandraceUnknownNPGRC/Tanzania
26TZA4000NchananaLandraceUnknownNPGRC/Tanzania
27TZA4010KagireLandraceUnknownNPGRC/Tanzania
28TZA4016MahindiLandraceUnknownNPGRC/Tanzania
29TZA4064Ya kienyejiLandraceUnknownNPGRC/Tanzania
30TZA4078MnanaLandraceUnknownNPGRC/Tanzania
31TZA4165IbahakaziLandraceUnknownNPGRC/Tanzania
32TZA4203GembeLandraceUnknownNPGRC/Tanzania
33TZA4205KatumbiliLandraceUnknownNPGRC/Tanzania
34TZA4320MahindiLandraceUnknownNPGRC/Tanzania
35JL01DT-STR-Y-SYN14OPVResistantIITA/Nigeria
36JL02DT-STR-Y-SYN15OPVResistantIITA/Nigeria
37JL03DT-STR-W-SYN11OPVResistantIITA/Nigeria
38JL04DT-STR-W-SYN13OPVResistantIITA/Nigeria
39JL05STR-SYN-Y2OPVResistantIITA/Nigeria
40JL06TZB-STR-SusceptibleOPVResistantIITA/Nigeria
41JL08Z. Diplo.BC4C3-W-DTC1OPVResistantIITA/Nigeria
42JL09TZECOMP3DT/white DT-STRR-SYNDC2OPVResistantIITA/Nigeria
43JL119022—13 Hybrid (Resistant)OPVResistantIITA/Nigeria
44JL12SAMMAZ—16OPVResistantIITA/Nigeria
45JL13TZECOMP5C7/TZECOM3DT.C2OPVResistantIITA/Nigeria
46JL151 WDC3SYN*2 white DSTR-SYN-DTC1OPVResistantIITA/Nigeria
47JL162*TZECOMP3DT/W DSTR/SYN DC2OPVResistantIITA/Nigeria
48JL17TZLCOMP1-WCB*2C W DT-STR-SYNJ-DTC1OPVResistantIITA/Nigeria
49JL18STR-SYN-W1OPVResistantIITA/Nigeria
50JL19DT-STR-W-SYN12OPVResistantIITA/Nigeria
51JL20Z. DIPLO-BC4-C3-W/DOGONA-1/Z.DIPLO-BC4-C3-WOPVResistantIITA/Nigeria
52JL21TZCOM 1/ZDP-SYNOPVResistantIITA/Nigeria
53JL22SITUKA M1OPVUnknownTARI/Tanzania
54JL23STAHAOPVUnknownTARI/Tanzania
55JL24T104OPVUnknownTARI/Tanzania
56JL25T105OPVUnknownTARI/Tanzania
S/No—serial number, NPGRC—National Plant Genetic Resources Centre for Tanzania, TARI—Tanzania Agricultural Research Institute, IITA—International Institute of Tropical Agriculture, OPV—Open Pollinated Variety, *—denotes a cross
Table
Table 2. Analysis of variance on maize and Striga traits recorded from 56 maize genotypes evaluated under Striga hermonthica infestation with and without FOS treatments in western Tanzania during 2017/18 growing season.
Table 2. Analysis of variance on maize and Striga traits recorded from 56 maize genotypes evaluated under Striga hermonthica infestation with and without FOS treatments in western Tanzania during 2017/18 growing season.
Maize Agronomic TraitsStriga hermonthica Traits
Source of VariationD.F.50% AD50% SDASIPHEHDMAGBGYDHKWTShDR8ShDR10ShEC8ShEC10
Replication238.12794.43714.6751626.318.210.7210870.51892.99.7320.33330.99113.25624.93
FOS124.453ns0.525 ns17.813 ns1163.6 ns298 ns20.57 *10639.5 ns308.5 ns0.236 **0.2976 *0.8601 ns0.0031 ns0.5481 ns
Error (a)27.21517.44710.091767.31431.072750.8507.90.0020.01190.18151.20281.72
Genotypes55129.846 ***178.788 ***15.674 ***8997.1 ***10113.9 ***310.47 ***18793.6 ***2752.6 ***132.433 ***0.6249 ***0.9761 ***2.0178 ***2.6799 ***
FOS x Genotypes558.506 ***11.008 ***6.87 ***1384.3 ***897.9 ***23.82 **2250.1 ***572.9 ***0.095 ns0.1522 ns0.1631 ns0.687 ***0.8489 ***
Error (b)2203.8694.523.037397.8333.314.93885.3204.91.2580.15440.17420.34590.3781
Total335
*, **, *** Significant at p < 0.05, p < 0.01 and p < 0.001 probability level, respectively, ns—not significant at p < 0.05 probability level, D.F.= Degrees of freedom, 50% AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, 50% SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking-interval, PH—Plant height (cm), EH—Ear height (cm), DM—Days to maturity, AGB—Above-ground biomass recorded as the weight (g) of above-ground plant parts, GYD—Grain yield/plant (g), HKWT—Weight of 100 kernel (g), ShDR8—Striga hermonthica damage rating recorded eight weeks after sowing, ShDR10—Striga hermonthica damage rating recorded ten weeks after sowing, ShEC8—Number of emerged S. hermonthica plants (count) recorded eight weeks after sowing, ShEC10—Number of emerged S. hermonthica plants (count) recorded ten weeks after sowing, FOS = Fusarium oxysporum f. sp. strigae.
Table
Table 3. Mean performance for 56 maize genotypes evaluated under Striga hermonthica infestation with (+) and without (−) FOS during 2017/2018 growing season.
Table 3. Mean performance for 56 maize genotypes evaluated under Striga hermonthica infestation with (+) and without (−) FOS during 2017/2018 growing season.
50% AD50% SDASIPHEHGYDHSWTAGBShEC8ShEC10ShDR8ShDR10
Accessions−+−+−+−+−+−+−+−+−+−+−+−+
TZA59967.5668.6770.0070.002.441.33289.42303.25195.50230.0072.2776.8831.7632.00141.70165.007.2811.657.2015.992.002.002.332.33
TZA60466.1166.3370.2272.674.116.33280.75259.75189.83164.5082.5695.9625.0125.22179.20217.507.2313.3110.8717.661.672.002.332.33
TZA61566.2265.3368.5667.672.332.33289.25296.25192.75183.7571.4589.6320.6020.45208.30230.006.721.9510.622.191.331.001.671.00
TZA68762.3361.0063.5664.671.223.67280.58285.25171.58189.2586.2767.5719.3718.98131.00120.002.955.935.488.621.331.001.671.67
TZA177163.8964.3365.6769.001.784.67272.08270.25145.92150.2571.3971.1623.2423.45123.30115.0012.253.6817.115.352.001.332.001.67
TZA177565.5665.3367.3366.671.781.33280.22283.15160.33154.5088.4683.6724.5824.72154.20152.504.873.326.615.001.001.001.001.00
TZA178074.8975.3378.0076.003.110.67271.25328.75177.33200.0087.5477.6420.3920.29289.20327.506.6110.749.9314.431.001.331.671.67
TZA178275.1172.0080.5679.675.447.67332.17341.00239.33263.5049.6866.4524.9225.05185.80222.509.578.1414.4410.872.671.672.001.67
TZA178467.0067.0072.4472.005.445.00295.92313.75242.25206.2545.6247.1628.9229.05193.30235.002.194.284.705.971.001.001.001.00
TZA226364.7864.3367.3368.672.564.33293.92294.25190.58194.25119.6097.9327.7027.83180.00135.002.946.286.358.551.001.001.331.33
TZA274961.4461.0064.0064.672.563.67273.35313.75148.08151.2585.9084.3825.4525.58100.00105.003.901.424.001.421.331.001.331.00
TZA276164.5664.3366.3367.671.783.33263.33291.50152.17162.5085.3366.3625.7625.88144.20142.503.562.655.602.951.001.001.001.00
TZA288167.3366.0069.7870.002.444.00336.25336.75222.17217.5068.1770.1522.3522.48187.50197.505.157.487.6611.491.671.671.672.00
TZA309566.3365.6771.3370.675.005.00284.25316.25184.42186.2575.7486.8126.0126.14100.00100.005.605.448.627.961.001.331.331.33
TZA318168.5667.6771.1168.002.560.33313.83270.00180.17183.0056.7850.3421.1921.3298.3090.001.9510.084.4413.761.002.001.002.00
TZA341761.3362.0062.2262.670.890.67279.83299.50161.17172.5070.2993.9620.5620.54135.80127.503.323.233.963.841.001.001.001.00
TZA350254.3353.0059.5656.675.223.67255.25260.75150.25177.7559.7865.9219.5018.9375.8072.500.892.821.643.561.001.001.001.00
TZA356168.6764.6772.4468.003.783.33318.67347.00212.25221.7550.5173.1021.9622.09148.30165.005.987.338.5110.662.001.672.332.33
TZA357066.4466.0068.3367.671.891.67293.92282.75179.72173.7564.2360.8522.4022.53107.50122.508.002.6511.993.651.331.332.331.67
TZA361466.4465.3369.3368.672.893.33326.33354.00207.17231.5084.7777.1524.9225.05161.70170.005.292.657.532.651.331.001.331.00
TZA382769.1168.0072.6770.003.562.00308.00335.00168.50202.5091.01128.1131.7931.92164.20217.502.242.713.844.441.001.001.001.00
TZA394258.2258.6758.6758.000.44−0.67246.67252.50146.00138.0070.3359.0227.1927.04103.3080.002.743.624.173.961.001.001.001.00
TZA395163.2262.3365.6765.672.443.33303.50319.00166.33179.0050.2050.2931.3231.45156.70185.003.322.484.974.441.001.001.001.00
TZA395264.7863.0070.7867.006.004.00313.25345.75177.00179.0040.5345.5929.8429.97149.20157.501.163.323.005.001.001.001.001.00
TZA396465.8962.3368.2266.672.334.33330.00298.00204.00182.0038.4751.5232.4532.72166.70150.002.103.324.423.961.001.001.001.00
TZA400062.5663.6763.0065.000.441.33291.83292.50152.67146.0094.4891.2026.8727.00112.50122.507.643.4910.993.681.671.332.001.33
TZA401058.6758.0062.2262.673.564.67307.75316.25163.00160.0088.0197.6130.9331.07104.20137.500.891.640.871.931.001.001.001.00
TZA401665.5665.3367.0067.001.441.67266.67260.00141.67140.0070.7270.6321.0721.21102.5097.504.762.324.972.951.331.331.671.00
TZA406465.7866.0068.2270.672.444.67331.33315.00207.92188.7580.4773.7534.7834.88178.30185.001.933.862.796.101.001.001.001.00
TZA407864.6768.6769.3372.674.674.00310.83312.50199.58203.7553.9855.6727.8227.95151.70135.006.673.526.172.951.671.331.671.00
TZA416567.6767.6767.3368.67−0.331.00246.17212.50145.42118.7582.6881.0723.2523.52102.50102.506.070.009.370.871.331.001.671.00
TZA420371.0071.0073.0071.672.000.67272.67276.00164.17177.5085.6391.9124.4124.54270.00335.000.890.501.931.421.001.001.001.00
TZA420561.7862.0062.7863.001.001.00274.17237.50129.58126.7586.7277.2123.8523.99151.70155.003.664.164.975.281.001.001.331.33
TZA432069.6771.6774.3375.674.674.00285.92307.75182.08208.7576.9177.0323.2523.38221.70270.000.000.000.000.001.001.001.001.00
JL0163.1163.3364.2264.671.111.33270.50251.50138.08126.7579.8682.8823.1422.99111.70115.003.3210.944.9713.641.331.671.002.00
JL0261.1161.3362.2262.671.111.33265.75244.75126.92112.2597.64121.7422.6422.54121.70105.005.793.848.434.701.331.331.331.00
JL0361.7862.0062.6762.670.890.67277.50275.00137.75144.7573.35101.3423.4323.56135.00140.003.271.645.662.001.001.001.001.00
JL0461.7862.0062.5663.670.781.67257.08257.75139.08124.7548.6860.4124.7824.91132.50147.500.501.700.872.651.001.001.001.00
JL0561.7862.0062.2262.670.440.67237.25231.75130.33117.5090.3189.2521.1721.30139.20172.501.421.641.641.931.001.001.001.00
JL0663.5664.6764.8968.671.334.00226.25257.25124.08156.2592.2393.7919.0118.56102.50127.509.415.0011.866.662.331.332.001.67
JL0864.0064.6763.7864.00−0.22−0.67252.33246.00141.08131.25117.56117.4821.6921.83164.20192.508.717.3311.0210.002.001.332.001.67
JL0961.1161.3362.0062.000.890.67217.92216.25110.00104.5088.7393.3621.6821.81114.20102.500.272.191.003.361.001.001.001.00
JL1162.4462.0063.6763.671.221.67267.50266.00138.92133.2587.1790.4420.1119.96100.80107.504.545.296.797.921.001.001.331.00
JL1264.8965.3366.0068.671.113.33287.67300.00151.58153.7556.5672.5622.6122.74119.20132.504.263.003.563.961.001.001.001.00
JL1360.1159.0061.5660.671.441.67234.00225.5099.75110.7573.9487.1120.7719.18100.80102.504.533.926.066.611.331.332.001.33
JL1562.1162.3364.0064.671.892.33246.17237.00126.92114.7568.9568.8221.9522.08104.20102.501.701.422.191.421.001.001.001.00
JL1661.0061.0061.2259.670.22−1.33233.67234.00114.67114.0089.0294.0819.7319.58134.20142.503.462.324.632.651.001.001.331.00
JL1764.3363.6765.7864.001.440.33290.83305.00145.00153.0080.2788.4621.8421.97161.70160.001.951.642.951.641.001.001.001.00
JL1863.0063.0063.8963.670.890.67236.33230.00116.50124.0094.6696.2623.8423.97158.30210.000.870.002.791.001.001.001.001.00
JL1965.1164.0066.7867.001.673.00211.58235.7583.0081.5079.8694.2219.6719.29119.20127.503.653.964.664.971.001.001.001.00
JL2064.0064.6764.3365.000.330.33255.25251.25136.17124.5075.6277.1622.7622.89180.80182.500.704.161.644.441.001.001.001.00
JL2162.4463.3363.8963.671.440.33259.20252.50144.08141.7563.7776.4222.5822.71141.70165.002.322.653.843.561.001.001.331.00
JL2253.1153.3355.4455.002.331.67233.92230.75115.50117.0067.0668.6023.9623.8080.8082.502.953.653.564.591.001.001.001.00
JL2363.3362.6765.8965.002.562.33289.33336.00155.92179.2553.1486.7626.6226.75130.80107.505.603.005.764.001.331.001.001.00
JL2461.4460.3362.8962.671.442.33297.50257.50146.75132.7595.84102.0128.1928.32173.30170.004.285.156.615.541.001.001.001.33
JL2563.8962.3366.6766.002.783.67215.58224.7598.5098.0089.95107.0927.2927.41127.50112.509.0013.0911.6315.451.672.332.332.00
Mean64.2363.9666.3966.362.162.40276.47280.26158.42160.0275.9080.7824.3724.40143.50152.704.164.245.935.651.251.191.361.26
CV3.13.213.97.111.317.54.618.728.525.832.231.8
p < 0.05************************************************************************
LSD2.953.192.6230.2928.7021.531.6844.870.971.020.630.67
*** Significant at p < 0.001 probability level, CV%—Coefficient of variation, LSD—Least significant difference, 50% AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, 50% SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking interval, PH—Plant height (cm), EH—Ear height (cm), GYD—Grain yield/plant (g), HKWT—Weight of 100 kernel (g), AGB—Above-ground biomass recorded as the weight (g) of above-ground plant parts, ShEC8—Number of emerged S. hermonthica plants (count) recorded eight weeks after sowing, ShEC10—Number of emerged S. hermonthica plants (count) recorded ten weeks after sowing, ShDR8—S. hermonthica damage rating recorded eight weeks after sowing, ShDR10—S. hermonthica damage rating recorded ten weeks after sowing, Note: bold faced text show selected genotypes.
Table
Table 4. Mean performance of maize genotypes without FOS or Striga infestation.
Table 4. Mean performance of maize genotypes without FOS or Striga infestation.
Accessions50% AD50% SDASIPHEHDMGYDHSWTAGB
TZA59967.5669.001.44286.67173.50127.0087.2832.112162.70
TZA60471.1173.892.78291.00221.08130.6787.9525.35279.20
TZA61566.5667.220.67306.25140.25115.8995.5620.522238.30
TZA68759.3363.564.22297.08207.58113.0098.4718.929142.00
TZA177165.8971.675.78268.08158.67126.8989.8923.584235.80
TZA177566.8968.331.44307.97192.58121.7893.2424.931229.20
TZA178074.2279.004.78314.50216.33135.6791.5220.385354.20
TZA178275.4479.223.78338.42249.58123.7855.8925.265280.80
TZA178470.6775.444.78326.17194.25131.5657.6629.265308.30
TZA226363.4465.331.89321.92212.83118.67112.8028.035295.00
TZA274961.7866.004.22304.95161.58122.00100.6325.801145.00
TZA276163.5665.001.44341.58205.92121.00104.2126.088249.20
TZA288168.3369.781.44358.25226.92119.8980.6122.695210.00
TZA309565.3372.677.33287.25170.17117.6787.8526.355145.00
TZA318169.5673.443.89282.83128.17117.5658.8521.532133.30
TZA341762.0062.890.89313.58161.67108.1182.9520.555138.30
TZA350255.3357.562.22281.50163.00110.0063.0518.888.30
TZA356165.6766.440.78373.17250.50116.6772.4322.308228.30
TZA357063.7864.670.89304.92185.77113.3383.7222.75157.50
TZA361467.4467.670.22347.58213.42118.6798.3325.261236.70
TZA382765.4467.331.89338.00196.25117.78146.6432.138184.20
TZA394263.2266.333.11267.17151.25125.0088.7727.117133.30
TZA395162.2264.672.44354.75231.83127.7881.0331.669201.70
TZA395270.1172.782.67352.25161.00119.3355.7230.187176.70
TZA396461.8966.224.33304.00144.00122.3345.9232.8186.70
TZA400061.5664.673.11259.33179.92109.6797.0827.221132.50
TZA401061.3363.892.56320.25171.50119.56126.6031.285149.20
TZA401665.8968.002.11323.17192.17120.56124.1021.419125.00
TZA406466.1168.892.78336.83188.67123.67100.8235.129213.30
TZA407866.6767.671.00328.33212.08109.4479.2928.161174.20
TZA416562.0063.331.33231.42100.67114.3399.4523.597145.00
TZA420366.0067.331.33267.92152.17128.0094.2524.751309.00
TZA420564.7863.11−1.67238.42120.83115.1193.7124.202156.70
TZA432067.0069.672.67297.17213.33127.67111.7923.599319.20
JL0158.1161.893.78256.60118.08114.0083.7523.057134.20
JL0263.7864.220.44248.25134.42121.00111.5222.638141.70
JL0363.1164.671.56349.00159.75121.4485.2223.775167.50
JL0462.1164.222.11302.33128.83114.6779.0825.126142.80
JL0563.7863.890.11242.25132.08116.56105.7021.517141.50
JL0670.5674.894.33296.75191.83120.0098.6918.478195.00
JL0864.3363.78−0.56249.58140.33120.00123.1922.041184.20
JL0961.1161.670.56247.42124.75122.78137.3222.023174.20
JL1161.7864.672.89308.75149.67114.0095.3220.036115.80
JL1266.2268.001.78297.42163.08116.67107.2822.948184.20
JL1360.4461.561.11246.25162.50113.78111.1118.536148.30
JL1562.1164.332.22272.92151.92116.5685.2822.291136.70
JL1659.0060.221.22224.92103.42116.44113.0419.655179.20
JL1763.6764.110.44274.58151.00115.6795.0122.177186.70
JL1861.0061.890.89217.58100.75124.67104.1924.174255.80
JL1965.4466.110.67224.08103.50113.78111.4919.25176.70
JL2061.3363.001.67338.00134.92122.22114.2023.105213.30
JL2162.4462.890.44262.65169.33126.5666.6122.925214.20
JL2252.1154.442.33264.17127.00111.6771.9723.866120.80
JL2366.6768.561.89351.08173.42116.3395.0226.958208.30
JL2464.1164.890.78278.75149.50120.11132.2428.526208.30
JL2563.2264.331.11253.33103.25126.3397.0327.623180.00
Mean64.36766.4442.077294.27166.48119.5693.8624.545190.6
CV3.13.213.97.111.33.317.54.618.7
p < 0.05***************************
LSD2.763.042.4828.6725.265.3320.191.5542.22
*** Significant at p < 0.001 probability level, CV%—Coefficient of variation, LSD—Least significant difference, 50% AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, 50% SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking interval, PH—Plant height (cm), EH—Ear height (cm), DM—Days to maturity, GYD—Grain yield/plant (g), HKWT—Weight of 100 kernel/seed (g), AGB—Above-ground biomass recorded as the weight (g) of above-ground plant parts.
Table
Table 5. Analysis of variance on maize and Striga traits recorded from 56 maize genotypes evaluated under Sa infestation, with and without FOS treatments, in western Tanzania during 2017/18 growing season.
Table 5. Analysis of variance on maize and Striga traits recorded from 56 maize genotypes evaluated under Sa infestation, with and without FOS treatments, in western Tanzania during 2017/18 growing season.
Maize Agronomic TraitsStriga asiatica
Source of VariationD.F.50% AD50% SDASIPHEHDMAGBGYDHKWTSaDR8SaDR10SaEC8SaEC10
Replication249.264207.48465.9927351898.218.336783.1290.512.41.41370.91374.4975.326
FOS10.001 ns31.787 ns31.433 ns1854.1 **0.3 ns61.51 ns19955.6 *2670.3 *0.802 *1.4405 *4.2976 *0.163 ns0.024 ns
Error (a)25.2573.36112.5912.61681.93.86429.853.60.0110.03870.05651.332.146
Genotypes55129.806 ***173.585 ***15.509 ***10083.4 ***10348.8 ***296.16 ***23699.4 ***2669.2 ***133.468 ***1.5117 ***2.2907 ***9.538 ***9.879 ***
FOS x Genotypes557.914 **14.433 ***8.459 ***1132.1 ***636.1 *29.9 ***1689.8 ***501.6 ***0.024 ns0.3314 ns0.3825 ns2.296 **2.583 ***
Error (b)2204.4546.4743.799376.7442.613.77924.5214.81.250.3050.41241.2761.246
Total335
*, **, *** Significant at p < 0.05, p < 0.01 and p < 0.001 probability level, respectively, ns—not significant at p < 0.05 probability level, D.F– Degrees of freedom, 50% AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, 50% SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking interval, PH—Plant height (cm), EH—Ear height (cm), DM—Days to maturity, AGB—Above-ground biomass recorded as the weight (g) of all plants parts above the ground, GYD—Grain yield/plant (g), HKWT—Weight of 100 kernel/seed (g), SaDR8—S. asiatica damage rating recorded eight weeks after sowing, SaDR10—S. asiatica damage rating recorded ten weeks after sowing, SaEC8—Number of emerged S. asiatica plants (count) recorded eight weeks after sowing, SaEC10—Number of emerged S. asiatica plants (count) recorded ten weeks after sowing, FOS—Fusarium oxysporum f. sp. strigae.
Table
Table 6. Mean performance for 56 maize genotypes evaluated under Striga asiatica infestation with (+) and without (−) FOS during 2017/2018 growing season.
Table 6. Mean performance for 56 maize genotypes evaluated under Striga asiatica infestation with (+) and without (−) FOS during 2017/2018 growing season.
50% AD50% SDASIPHEHGYDHKWTAGBSaEC8SaEC10SaDR8SaDR10
Accessions−+−+−+−+−+−+−+−+−+−+−+−+
TZA59970.5669.0073.3372.002.783.00265.67292.50185.33220.0084.2088.7532.2932.39197.50217.5045.5232.0859.5239.323.002.003.332.00
TZA60467.0069.0071.6775.004.676.00299.75302.75209.50203.5087.2995.7025.5425.63206.70225.0011.8632.5916.2341.751.672.332.332.00
TZA61567.4467.0070.2271.332.784.33291.58296.75203.92199.7562.2462.2121.3021.00188.30140.0015.2726.5622.4029.642.002.003.002.67
TZA68759.6761.0062.5663.002.892.00273.00263.00158.50170.5073.2659.8519.8919.52123.30135.0013.0413.7217.3917.272.002.002.332.00
TZA177163.7864.0069.0067.005.223.00254.67228.00157.83157.5069.5761.3023.9423.87139.20147.5025.6326.5031.6032.532.332.002.672.33
TZA177564.7867.6766.3368.331.560.67274.42282.75165.50173.5084.4781.2925.1725.27193.30190.007.1325.2710.5732.951.001.671.002.00
TZA178072.6774.0076.1177.673.443.67289.08295.75199.00204.5098.09120.2920.9020.84318.30350.0011.6516.1216.6620.421.001.331.671.67
TZA178275.7875.3380.1177.674.332.33326.25333.25224.50226.0046.4261.6325.4925.59281.70260.0017.2734.6221.0945.281.672.333.002.33
TZA178467.2269.0071.3372.004.113.00316.83331.00212.00222.0043.3045.0329.4929.59198.30235.0022.875.4231.088.552.331.672.331.67
TZA226365.0065.0067.4465.002.440.00304.17320.00184.42199.25103.3295.5528.2628.36163.30185.0010.029.0014.6112.001.331.002.001.33
TZA274962.4462.6764.1163.671.671.00283.33291.50149.25167.2571.4879.4326.0426.1489.2092.507.6610.5712.6316.541.001.332.001.33
TZA276161.8963.0063.1162.671.22−0.33263.58273.25169.75161.2594.2896.0026.3126.41185.00155.0010.9425.6115.6932.611.331.671.332.33
TZA288168.2266.6772.2266.674.000.00308.33339.00210.00212.5051.7460.6923.1523.02198.30215.0040.8225.3550.2529.313.002.333.001.67
TZA309563.8965.6768.6767.334.781.67262.42295.75156.08153.2561.4967.7526.5826.68121.70125.0027.8821.4833.6126.402.002.002.332.33
TZA318165.3366.6769.8968.334.561.67286.27258.80171.67167.0050.5674.3221.7621.8688.3095.008.373.0613.046.521.331.001.671.00
TZA341762.7865.6762.7862.330.00−3.33271.93278.30161.42134.7565.2168.6521.2320.9690.0080.0010.630.0015.271.421.671.001.671.00
TZA350255.6753.0059.0057.003.334.00240.42273.75114.92141.7549.8353.2319.8219.4765.0060.004.170.877.111.661.001.001.001.00
TZA356168.0068.6769.5671.331.562.67338.25324.25219.25225.2548.8639.1822.7722.64123.30155.0028.0836.1437.4748.002.332.333.333.00
TZA357065.6765.0065.8965.000.220.00318.92326.75210.83205.0068.2478.2922.9823.08110.00125.004.9728.856.4133.831.002.001.001.67
TZA361467.0067.0070.7869.003.782.00329.92351.25191.25216.2571.0289.4425.4925.59129.20127.5021.5117.8128.4221.822.331.332.331.33
TZA382766.5669.0068.4470.671.891.67293.92281.25157.42141.2568.8383.0832.3732.47177.50202.5028.2523.1935.5827.592.332.333.002.67
TZA394259.8955.6760.0054.670.11−1.00233.08248.25144.00140.5070.5668.3327.4827.58151.70125.001.421.573.173.961.001.001.001.00
TZA395162.4460.0064.7863.672.333.67308.08307.75176.58166.2570.3764.1031.9032.00141.70165.0024.9515.2829.7820.002.332.002.331.67
TZA395264.5663.0066.2266.001.673.00313.58284.75156.42153.2548.1253.1930.4230.52113.3085.000.8711.002.5214.991.001.001.001.33
TZA396461.5662.0062.4462.670.890.67293.50265.50166.67161.0040.9149.0032.9733.07160.00125.002.6415.344.4121.321.001.671.331.67
TZA400061.2261.6761.8961.670.670.00290.33343.50143.33166.0060.5469.5727.4627.5689.2087.509.006.0512.998.511.331.001.671.33
TZA401061.7862.6763.8965.672.113.00300.25313.75152.75169.7593.3780.4131.5231.62105.00130.007.454.2713.128.521.331.331.671.67
TZA401663.4465.0064.7866.331.331.33283.25286.25149.33160.0077.3575.8021.8121.75117.50112.5012.753.9217.616.101.671.001.001.33
TZA406466.7867.0071.4467.674.670.67341.25350.75200.75209.7563.8643.0035.2335.48212.50202.5016.3145.9025.5358.072.003.002.673.33
TZA407862.6762.0066.4466.673.784.67312.08331.25184.50207.5043.8740.4928.3928.49132.50147.5017.5515.1822.9518.671.671.672.332.00
TZA416562.8964.0063.8965.001.001.00243.42237.75126.00126.0092.49105.4623.9623.86104.2087.503.843.566.757.661.331.001.001.00
TZA420365.6767.6768.2273.332.565.67256.67252.50115.33155.0076.9984.8524.9825.08156.70145.007.647.9811.0211.991.671.001.331.00
TZA420561.6761.6763.3364.001.672.33245.42268.75142.92163.7597.56105.3424.4424.54124.20117.502.423.844.176.751.001.331.001.33
TZA432070.2268.6774.6771.334.442.67293.42308.75197.83197.5055.4060.9923.8323.93259.20317.500.500.271.422.001.001.001.001.00
JL0161.5662.0063.3363.331.781.33252.08243.75129.25118.7571.9665.3923.4323.53120.00150.002.8711.025.9016.352.001.001.331.33
JL0261.4461.6961.5662.000.110.33245.50248.00126.75133.7584.0390.1922.9823.08135.80152.5015.1816.8722.5621.021.671.672.332.00
JL0361.2260.3362.0059.330.78−1.00277.17259.00166.92140.2569.9080.8524.0124.1198.30115.004.264.987.538.281.001.331.001.33
JL0461.4461.0063.8962.332.441.33252.67256.00129.67137.0045.9837.9925.3525.4596.70120.003.966.277.7210.711.001.001.331.33
JL0562.0062.0061.5662.00−0.440.00236.08268.75117.58133.2594.9494.9121.9621.85130.00140.0014.435.5017.488.931.331.001.331.00
JL0665.7866.0066.6764.000.89−2.00244.50230.50143.17118.0079.8690.8319.4119.09126.70115.0035.9930.9943.1540.403.002.673.332.67
JL0862.7863.6763.7864.671.001.00248.17254.50139.58139.75106.58129.5122.4422.37130.80147.5016.7120.9521.6327.862.001.672.332.33
JL0961.3362.0061.1161.33−0.22−0.67218.25219.25113.08115.2576.3674.9522.2522.3590.80112.509.5112.1213.3516.871.671.331.671.33
JL1162.2262.6763.2263.671.001.00262.75269.25136.75136.2573.4078.1220.6520.5187.5092.5013.5611.3017.5515.001.331.001.331.33
JL1263.6765.0064.0065.330.330.33284.08287.25159.67165.0080.8172.3823.1823.27127.50127.501.112.712.195.541.001.001.001.00
JL1357.8957.0061.0061.003.114.00217.75226.25131.08157.2592.84109.3719.6219.72112.50112.5026.2814.0236.6717.942.332.003.002.00
JL1564.7863.0066.4466.001.673.00250.67262.00126.17121.0078.0978.0322.5222.62146.70165.008.313.6813.127.161.001.001.331.00
JL1665.8965.6766.3365.670.440.00203.33203.0090.9292.7580.4591.5820.4720.13113.30105.0013.6212.1217.8514.441.671.001.671.67
JL1763.6763.6764.0062.670.33−1.00264.17292.50142.00165.5082.7486.0222.4022.50102.5097.5019.637.7727.5510.762.001.331.671.33
JL1862.7863.0063.1164.000.331.00228.42243.75115.75117.2589.1793.8624.5524.49170.80167.502.794.505.487.381.001.001.001.00
JL1964.3365.6764.1165.00−0.22−0.67207.50204.5093.5886.2598.5291.8219.9019.83116.70115.0010.947.8713.7711.571.331.002.001.33
JL2062.6764.0064.0065.331.331.33250.17268.50135.08138.7584.3384.0823.3323.43135.00160.006.3813.0310.9417.661.001.331.331.67
JL2163.2265.6764.0065.330.78−0.33275.00293.00162.83152.5058.2874.2623.1523.25147.50152.506.074.178.527.531.001.001.001.00
JL2251.5652.0053.6753.672.111.67252.25252.75128.67114.5070.4268.8424.2424.34116.70135.0020.568.2626.9111.372.001.332.331.33
JL2364.0064.0067.8968.333.894.33316.17341.00162.92186.2586.2272.4727.1927.28144.20182.5022.2617.3227.6621.652.001.332.332.00
JL2461.5662.0062.5663.671.001.67260.50274.00138.17137.0090.6490.7128.7528.85186.70230.009.7210.6314.2513.641.331.001.331.00
JL2561.5662.0064.3366.332.784.33213.75218.75105.67108.5091.5797.7827.8527.95150.80192.5025.7325.7232.6133.682.332.003.002.00
Mean63.8164.0965.8465.652.031.57272.64279.56156.50160.5973.7977.0724.9124.93143.60150.9013.7614.3018.6918.921.631.491.871.64
CV%3.303.9025.606.9013.1018.204.5019.0031.8026.9035.4036.60
p < 0.05*************************************************************************
LSD3.22 4.09 3.03 29.32 33.86 21.98 1.68 45.68 1.821.810.881.03
*** Significant at p < 0.001 probability level, CV%—Coefficient of variation, LSD—Least significant difference, 50% AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, 50% SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking interval, PH—Plant height (cm), EH—Ear height (cm), GYD—Grain yield/plant (g), HKWT—Weight of 100 kernel (g), AGB—Above-ground biomass recorded as the weight (g) of all plants parts above the ground, SaEC8—Number of emerged S. asiatica plants (count) recorded eight weeks after sowing, SaEC10—Number of emerged S. asiatica plants (count) recorded ten weeks after sowing, SaDR8—S. asiatica damage rating recorded eight weeks after sowing, SaDR10—S. asiatica damage rating recorded ten weeks after sowing, Note: bold faced text show selected genotypes.
Table
Table 7. Pearson correlation coefficient (r) for maize agronomic traits recorded among 56 maize accessions under Striga hermonthica with FOS (above diagonal) and without FOS treatment (below diagonal).
Table 7. Pearson correlation coefficient (r) for maize agronomic traits recorded among 56 maize accessions under Striga hermonthica with FOS (above diagonal) and without FOS treatment (below diagonal).
ADSDASIPHEHDMGYAGBHKWTShEC8ShEC10ShDR8ShDR10
AD10.85 **−0.100.25 **0.44 **0.47 **−0.070.54 **0.090.19 *0.21 **0.17 *0.22 **
SD0.93 **10.45 **0.45 **0.58 **0.47 **−0.150.51 **0.21 **0.27 **0.28 **0.22 **0.26 **
ASI0.29 **0.63 **10.31 **0.34 **0.09−0.17 *0.040.24 **0.20 *0.18 *0.130.12
PH0.35 **0.36 **0.21 **10.83 **0.12−0.080.31 **0.38 **0.060.080.040.07
EH0.95 **0.53 **0.32 **0.77 **10.22 **−0.19 *0.41 **0.32 **0.140.17 *0.140.21 **
DM0.48 **0.45 **0.16 *0.070.22 **10.080.66 **0.23 **0.130.150.080.10
GY−0.10−0.22 **−0.35 **−0.24 **−0.24 **0.0110.11−0.12−0.02−0.010.05−0.02
AGB0.46 **0.40 **0.080.29 **0.40 **0.58 **0.0710.15 *0.000.020.000.05
HKWT0.090.17 *0.23 **0.43 **0.38 **0.20 *−0.17 *0.17 *10.01−0.01−0.01−0.10
ShEC80.18 *0.11−0.090.000.050.050.02−0.01−0.0910.97 **0.70 **0.73 **
ShEC100.25 **0.16 *−0.100.040.100.080.080.04−0.100.92 **10.68 **0.75 **
ShDR80.19 *0.15 *0.000.090.15 *0.10−0.030.01−0.070.69 **0.60 **10.71 **
ShDR100.20 **0.14−0.050.000.070.100.070.01−0.120.71 **0.72 **0.65 **1
*, **, *** Significant at p < 0.05, p < 0.01 and p < 0.001 probability level, respectively, AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking interval, PH—Plant height (cm), EH—Ear height (cm), DM—Days to maturity, GY—Grain yield/plant (g), AGB—Above-ground biomass recorded as the weight (g) of above-ground plant parts, HKWT—Weight of 100 kernel (g), ShEC8—Number of emerged S. hermonthica plants (count) recorded eight weeks after sowing, ShEC10—Number of emerged S. hermonthica plants (count) recorded ten weeks after sowing, ShDR8—S. hermonthica damage rating recorded eight weeks after sowing, ShDR10—S. hermonthica damage rating recorded ten weeks after sowing.
Table
Table 8. Pearson correlation coefficient (r) for maize agronomic traits recorded among 56 maize accessions under Striga asiatica with FOS (above diagonal) and without FOS treatment (below diagonal).
Table 8. Pearson correlation coefficient (r) for maize agronomic traits recorded among 56 maize accessions under Striga asiatica with FOS (above diagonal) and without FOS treatment (below diagonal).
ADSDASIPHEHDMGYAGBHKWTSaEC8SaEC10SaDR8SaDR10
AD10.85 **0.010.344 **0.47 **0.50 **0.070.49 **0.060.29 **0.30 **0.18 *0.20 *
SD0.89 **10.53 **0.351 **0.51 **0.56 **0.020.52 **0.120.30 **0.31 **0.23 **0.26 **
ASI0.21 **0.64 **10.120.22 **0.26 **−0.080.21 **0.140.110.100.140.18 *
PH0.40 **0.45 **0.28 **10.78 **0.07−0.23 **0.31 **0.38 **0.18 *0.17 *0.18 *0.13
EH0.51 **0.55 **0.32 **0.78 **10.25 **−0.20 **0.44 **0.30 **0.35 **0.34 **0.36 **0.27 **
DM0.47 **0.44 **0.150.18 *0.34 **10.23 **0.74 **0.20 *0.21 **0.22 **0.18 *0.17 *
GYD−0.13−0.23 **−0.26 **−0.31 **−0.29 **0.0510.05−0.22 **−0.020.00−0.12−0.12
AGB0.54 **0.51 **0.18 *0.26 **0.52 **0.73 **0.0310.23 **0.25 **0.25 **0.23 **0.18 *
HKWT0.110.140.130.38 **0.23 **0.32 **−0.110.23 **10.19 *0.21 **0.18 *0.17 *
SaEC80.18 *0.23 **0.19 *0.060.21 **0.13−0.050.16 *0.1210.99 **0.78 **0.75 **
SaEC100.18 *0.23 **0.19 *0.060.21 **0.12−0.040.16 *0.130.99 **10.75 **0.74 **
SaDR80.16 *0.21 **0.16 *0.100.19 *0.09−0.070.100.100.87 **0.85 **10.78 **
SaDR100.26 **0.31 **0.22 **0.16 *0.26 **0.10−0.040.18 *0.100.80 **0.81 **0.77 **1
*, **, *** Significant at p < 0.05, p < 0.01 and p < 0.001 probability level, respectively, AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking interval, PH—Plant height (cm), EH—Ear height (cm), DM—Days to maturity, GY—Grain yield/plant (g), AGB—Above-ground biomass recorded as the weight (g) of all plants parts above the ground, HKWT—Weight of 100 kernel (g), SaEC8—Number of emerged S. asiatica plants (count) recorded eight weeks after sowing, SaEC10—Number of emerged S. asiatica plants (count) recorded ten weeks after sowing, SaDR8—S. asiatica damage rating recorded eight weeks after sowing, SaDR10– S. asiatica damage rating recorded ten weeks after sowing.
Table
Table 9. Eigenvalues explained variance and rotated component matrix of nine agronomic traits and four Striga hermonthica (Sh) parameters among 56 maize genotypes evaluated under Sh infestation with and without FOS treatments in Tanzania.
Table 9. Eigenvalues explained variance and rotated component matrix of nine agronomic traits and four Striga hermonthica (Sh) parameters among 56 maize genotypes evaluated under Sh infestation with and without FOS treatments in Tanzania.
Traits—Assessed under Sh Infestation without FOS TreatmentRotated Component MatrixTraits—Assessed under Sh Infestation with FOS TreatmentRotated Component Matrix
PC1PC2PC3PC1PC2PC3
AD0.300.810.29AD0.210.840.22
SD0.270.760.49SD0.260.740.48
ASI0.050.220.75ASI0.210.060.73
PH0.070.230.84PH−0.010.300.82
EH0.180.400.81EH0.170.390.80
DM0.000.850.03DM0.100.820.00
GYD0.070.18−0.70GYD0.050.18−0.59
HSWT−0.170.120.57HSWT−0.070.130.55
AGB−0.090.910.10AGB−0.060.920.07
ShEC80.960.03−0.05ShEC80.950.100.03
ShEC100.930.11−0.02ShEC100.950.140.05
ShDR80.890.050.09ShDR80.930.060.03
ShDR100.910.08−0.04ShDR100.940.100.05
Eigen value3.653.093.07Eigen value3.763.102.79
Proportion variance (%)28.0623.7723.64Proportion of Variance (%)28.9023.8521.43
Cumulative variance (%)28.0651.8375.47Cumulative Variance (%)28.9052.7674.19
50% AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, 50% SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking interval, PH—Plant height (cm), EH—Ear height (cm), DM—Days to maturity, GYD—Grain yield/plant (g), HKWT—Weight of 100 kernel (g), AGB—Above-ground biomass recorded as the weight (g) of above-ground plant parts, ShEC8—Number of emerged S. hermonthica plants (count) recorded eight weeks after sowing, ShEC10—Number of emerged S. hermonthica plants (count) recorded ten weeks after sowing, ShDR8—Striga hermonthica damage rating recorded eight weeks after sowing, ShDR10—Striga hermonthica damage rating recorded ten weeks after sowing, PC1, PC2, and PC3—denote Principal components 1, 2, and 3, respectively, Bolded values indicates traits with main contribution in a respective principal component.
Table
Table 10. Eigenvalues explained variance and rotated component matrix of nine agronomic traits and four Striga asiatica (Sa) parameters among 56 maize genotypes assessed under Sa infestation with and without FOS treatments in Tanzania.
Table 10. Eigenvalues explained variance and rotated component matrix of nine agronomic traits and four Striga asiatica (Sa) parameters among 56 maize genotypes assessed under Sa infestation with and without FOS treatments in Tanzania.
Traits—Assessed under Sa Infestation without FOS TreatmentRotated Component MatrixTraits—Assessed under Sa Infestation with FOS TreatmentRotated Component Matrix
PC1PC2PC3PC1PC2PC3PC4
AD0.140.800.31AD0.240.890.15−0.18
SD0.240.790.43SD0.240.880.160.15
ASI0.350.360.52ASI0.060.260.070.76
PH0.040.240.88PH0.090.330.860.07
EH0.150.460.76EH0.250.510.710.13
DM0.080.89−0.01DM0.150.75−0.230.49
GYD0.010.19−0.79GYD−0.070.29−0.73−0.10
HKWT0.050.190.43HKWT0.18−0.030.440.61
AGB0.050.920.14AGB0.150.750.040.39
SaEC80.970.120.05SaEC80.940.230.100.06
SaEC100.970.120.05SaEC100.940.230.100.06
SaDR80.950.040.06SaDR80.920.120.140.12
SaDR100.910.150.16SaDR100.930.120.080.10
Eigen value3.853.442.78Eigen value3.763.342.121.45
Proportion of Variance (%)29.6126.4421.42Proportion of Variance (%)28.9125.7216.2911.16
Cumulative Variance (%)29.6156.0577.47Cumulative Variance (%)28.9154.6370.9282.08
50% AD—Number of days from sowing to when 50% of the plants in a plot shed pollen, 50% SD—Number of days from sowing to when 50% of the plants in a plot produce silk, ASI—Anthesis-silking interval, PH—Plant height (cm), EH—Ear height (cm), DM—Days to maturity, GYD—Grain yield/plant (g), HKWT—Weight of 100 kernel (g), AGB—Above-ground biomass recorded as the weight (g) of above-ground plant parts, SaEC8—Number of emerged Striga asiatica plants (count) recorded eight weeks after sowing, ShEC10—Number of emerged Striga asiatica plants (count) recorded ten weeks after sowing, SaDR8—Striga asiatica damage rating recorded eight weeks after sowing, SaDR10—Striga asiatica damage rating recorded ten weeks after sowing. PC1, PC2, and PC3—denote Principal components 1, 2, and 3, respectively.
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Lobulu, J.; Shimelis, H.; Laing, M.D.; Mushongi, A.A.; Shayanowako, A.I.T. Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania. Agronomy 2021, 11, 1004. https://doi.org/10.3390/agronomy11051004

AMA Style

Lobulu J, Shimelis H, Laing MD, Mushongi AA, Shayanowako AIT. Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania. Agronomy. 2021; 11(5):1004. https://doi.org/10.3390/agronomy11051004

Chicago/Turabian Style

Lobulu, John, Hussein Shimelis, Mark D. Laing, Arnold Angelo Mushongi, and Admire Isaac Tichafa Shayanowako. 2021. "Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania" Agronomy 11, no. 5: 1004. https://doi.org/10.3390/agronomy11051004

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