Crops

The brown planthopper, Nilaparvata lugens (Stål)[BPH], is a damaging pest of rice in Asia. Insecticides and rice varietal resistance are widely implemented BPH management practices. However, outbreaks of BPH have been linked to excessive insecticide use—challenging the compatibility of these two management practices. IR62 is a variety with resistance against BPH, the whitebacked planthopper, Sogatella furcifera Horváth [WBPH], and the green leafhopper, Nephotettix virescens (Distant)[GLH]. We compared BPH responses to IR62 and to the susceptible variety IR64 treated with buprofezin, carbofuran, cartap hydrochloride, cypermethrin, deltamethrin, fipronil, or thiamethoxam + chlorantraniliprole. In greenhouse bioassays, cypermethrin, fipronil and thiamethoxam + chlorantraniliprole reduced egg laying on both varieties, and, together with buprofezin, reduced nymph survival to zero. Buprofezin, carbofuran, and cartap hydrochloride stimulated egg laying, and carbofuran increased nymph biomass, but these effects were reduced on IR62. Planthopper populations were ten times higher on deltamethrin-treated rice than untreated rice in a screenhouse experiment. Host resistance failed to buffer against this insecticide-induced resurgence in BPH and WBPH. However, IR62 reduced the effect in GLH. Rice treated with cypermethrin and fipronil had reduced yields compared to untreated controls, suggesting possible phytotoxic effects. We found little evidence of synergies between the two management practices; but host resistance did buffer against the undesirable effects of some insecticides. Full article

Seedling vigor and regrowth ability are important traits for the forage production of winter wheat. The objectives of this study were to map quantitative trait loci (QTL) associated with seedling vigor and regrowth vigor traits using a genome-wide association mapping study (GWAS). Seedling vigor and regrowth vigor were evaluated with shoot length, the number of shoots per plant and shoot dry weight per plant 45 days after planting and 15 days after cutting. A large phenotypic variation was observed for all the traits studied. In total, 12 significant QTL for seedling vigor and 16 for regrowth vigor traits were detected on various chromosomes. Four QTL on chromosomes 2B, 4B, 5A and 7A for seedling vigor co-localized with QTL for regrowth vigor due to significant correlations between corresponding traits of the initial growth and regrowth. A BLAST search using DNA sequences of the significant loci revealed candidate genes playing roles in vegetative and reproductive development in different crop species. The QTL and single-nucleotide polymorphism (SNP) markers identified in this study will be further validated and used for marker-assisted selection of the traits during forage wheat breeding. Full article

Alfalfa (Medicago sativa L.) establishment failure is often attributed to autotoxicity when alfalfa is reseeded shortly after termination of the previous alfalfa stand, but renovation/rotation strategies for irrigated semiarid, subtropical environments have not been studied. Two identical studies were initiated at the New Mexico State University Rex E. Kirksey Agricultural Science Center at Tucumcari, NM, USA to compare continuous alfalfa (ALF), a single year of rotation to sorghum-sudangrass (SS1; Sorghum bicolor × S. sudanense (Piper) Stapf), two years of rotation with sorghum-sudangrass (SS2), and winter wheat forage (Triticum aestivum L.) followed by a single season of sorghum-sudangrass (WW/SS). Soil type and renovation/rotation strategy may influence soil fertility prior to replanting alfalfa, but soil fertility did not appear to influence alfalfa re-establishment or first production year yields. With a Test x Rotation interaction due to differences between tests for WW/SS for first production year yield after September alfalfa replanting, the main effect of Rotation was significant for yield (6.43AB, 5.3B0, 6.92A, and 3.54C Mg ha⁻¹ for ALF, SS1, SS2, and WW/SS, respectively; 5% LSD = 1.22). Alfalfa stand destruction and replanting with no intervening crop rotation may be feasible in sandy soils with irrigation in the semiarid, subtropical southwestern USA and similar environments. Full article

The genetic diversity of cultivated rice in farmers’ fields remains understudied in West Africa despite the importance of rice for food security in this region. In this study, we genotyped rice samples from Burkina Faso using the C6AIR SNP (Single Nucleotide Polymorphism) array (IRRI), including 27 registered cultivars and 50 rice samples collected in rice fields from three geographical zones in western Burkina Faso. Most of the registered cultivars clustered with the indica genetic group, except seven assigned to japonica and one admix. All but one of the rice samples from farmers’ fields belonged to the indica group. The other field sample, which unexpectedly clustered with the Aus genetic group, originated from a rainfed lowland site known to differ in terms of agronomic practices, and which revealed to be highly differentiated from the five other sites. Apart from this peculiar site, the rice grown in irrigated areas did not differ from rice sampled in rainfed lowlands. Finally, obtained genetic data confirmed the high frequency of one cultivar, in congruence with farmers’ interviews. We argue on the importance to document and preserve the high agro-biodiversity observed in rice from Burkina Faso as a prerequisite to face the current challenges of growing rice demand and global change. Full article

Treating plants with elevated carbon dioxide (eCO₂) can increase their drought tolerance. Increased atmospheric CO₂, a fundamental factor in climate change, may compensate for the drought-induced reduction in crop growth and yield. Basil, being moderately sensitive to drought stress (DS), experiences several morphological changes under DS. Thus, we designed an experiment that addresses how DS and different levels of CO₂ affect the overall morphological growth patterns during basil’s early and late-season growth. The experiment was conducted under four different growth conditions: two water treatments, (1) a full-strength Hoagland’s solution was added to the basil plants at 120% of the evapotranspiration each day, and (2) 50% of the full-strength Hoagland’s solution was added to basil plants for the drought treatment, alongside two levels of CO₂ application [ambient 420 ppm (aCO₂) and elevated 720 ppm (eCO₂)]). The DS had a severe impact on the morphological traits of the shoot and root systems. Compared to control, DS reduced the marketable fresh mass (FM) by 31.6% and 55.2% in the early and late stages of growth. FM was highest under control + eCO₂ (94.4–613.7 g) and lowest under DS + aCO₂ (67.9–275.5 g). Plant height under DS + aCO₂ and DS + eCO₂ reduced by 16.8% and 10.6% during the late season. On the other hand, dry mass percent (DM%) increased by 31.6% and 55.2% under DS + eCO₂ compared to control in the early and late stages of growth, respectively. This study suggested that eCO₂ during DS significantly impacts basil morphological traits compared to aCO₂. Besides, anthocyanin decreased by 10% in DS + aCO₂ and increased by 12.6% in DS + aCO₂ compared to control. Similarly, nitrogen balance index, a ratio of chlorophyll and flavonoids, was recorded to be the highest in DS + aCO₂ (40.8) compared to any other treatments. Overall, this study indicates that the suppression of basil’s morphophysiological traits by DS is more prominent in its later growth stage than in the earlier stages, and eCO₂ played an important role in alleviating the negative effect of DS by increasing the DM% by 55%. Full article

Colletotrichum sublineola is a casual pathogen of sorghum anthracnose. Sorghum pathologists often need to conduct evaluations for anthracnose resistance in large scale which are expensive and labor intensive. As a solution, an excised-leaf assay has been used, but whether or not leaf age, position or region affects pathogenicity scores has not previously been evaluated. Essentially, in an excised-leaf assay, is response to C. sublineola over all or part of a leaf blade identical? To get an answer, three sorghum and one Johnson grass cultivars were tested. The top five leaves were inoculated at the apex, mid-leaf and base of each leaf blade. Results show nearly no effect of leaf age to pathogenicity level within the top five leaves. Furthermore, in order to evaluate any protective role of leaf wax to C. sublineola, the wax was disrupted by simply wiping the leaf surface by a thumb, or as an alternative method, leaf surface tension was reduced by submerging leaves into 2% TWEEN 20 before inoculation. Compared to control, wiped leaves increased pathogenicity scores on the leaf blade and midrib in two of three sorghum cultivars, but 2% TWEEN 20-treated leaves had only minimal changes in pathogenicity level compared to controls. Full article

Tomato continues to be one of the most important crops worldwide, and protected cultivation is practiced to overcome the biotic and abiotic stresses to which the plant are exposed during growth. In this study we evaluated the effect of colored net houses on the growth, yield and nutritional values, as well as the incidence of common pests under three different light conditions: (1) colored (magenta), (2) conventional (white), and open field conditions. A colored net house led the plants to grow taller with higher lycopene content, but recorded a higher number of whiteflies, compared to the conventional net house and open field conditions. Furthermore, plants under protected structures recorded lower SPAD values, but larger terminal leaflets, lower damage by leaf miners, but more damage caused by spider mites compared to those plants grown under open field conditions. Overall, we found that the use of colored net houses provided a positive effect on tomato production in terms of improvement in morphometric parameters, however, to obtain higher yields under this production system, it is important to reduce the elevated temperature and increase the relative humidity inside the protective structures to be adapted for local growing conditions in Taiwan. Full article

Glyphosate is an extensively used herbicide because of its non-selective action for weed control. Salicylic acid (SA) is a phenolic compound that has the potential to increase plant tolerance to diverse stresses. To test SA ability to modulate plant responses to glyphosate we used young wheat (Triticum aestivum L.) seedlings grown as a water culture. Plants were sprayed with 1 mM SA, and 24 h later with 0.5 mM glyphosate. All measurements were performed 14 days after herbicide treatment. Wheat growth was reduced by glyphosate. Stress markers (proline and malondialdehyde) were significantly increased by glyphosate showing oxidative damages. Incapacity of wheat to cope with the oxidative stress was evidenced by reduction in thiols and phenolics content, accompanied by slight induction of superoxide dismutase and catalase activities. Enhanced activities of peroxidase, glutathione reductase and glutathione-S-transferase were expected to participate in glyphosate detoxification. SA applied alone had no important effects on measured parameters. SA pretreatment decreased stress markers and caused additional amplification of antioxidant defense systems in glyphosate-treated plants. Growth was partially restored in combine-treated plants due to SA application. SA probably triggered antioxidant defense to cope with the herbicide stress. Full article

Enhancing host defences through induced resistance, disease tolerance, and/or escape, in combination with current disease management regimes may be a valuable strategy to reduce pesticide use. Since both ‘on-farm’ seed priming (OSP) and chitosan priming (CHP) have been reported to confer varying levels of host defence, this study sought to investigate their potential to deliver disease control as a strategy for sustainable management of foliar pathogens in winter barley. Field experiments were conducted to determine the effects of OSP and CHP at two different field sites using three different cultivars under fungicide/non-fungicide regimes. Overall, no evidence was found to suggest that CHP or OSP can induce effective resistance in temperate field conditions. However, these field trials enabled the identification of candidate traits to deliver disease tolerance (and escape) for the primary and secondary spread of powdery mildew, i.e., large canopies and rapid stem elongation respectively. Thus, these seed treatments may deliver disease tolerance and escape traits, but these benefits are dependent upon successful establishment and vigour first. The integration of seed treatments into sustainable crop protection may be better undertaken with spring crops or in semi-arid agriculture where the added vigour at emergence can help compensate for negative environmental interactions. Full article

Collection of wheat landraces (WLR) was conducted in Afghanistan, Iran, and Turkey in 2010–2014. A representative subset of this collection was used in the current study and included 45 bread wheat landraces from Turkey, 19 from Iran, and 20 from Afghanistan. This material was supplemented by 73 modern cultivars and breeding lines adapted to semiarid conditions and irrigated conditions. Overall, 157 genotypes were tested in Turkey in 2018 and 2019 and in Afghanistan and Iran in 2019 under rainfed conditions to compare performance of WLR and modern material. The germplasm was genotyped using a high density Illumina Infinium 25K wheat SNP array and KASP markers for agronomic traits. The average grain yield ranged between 2.2 and 4.0 t/ha depending on the site and year. Three groups of landraces demonstrated similar average grain yield, though Afghanistan material was slightly higher yielding not only in Afghanistan but also in Turkey. Modern material outyielded the landraces in two environments out of four. The highest yielding landraces were competitive with the best modern germplasm. Frequency of gene Sus2-2B affecting 1000 kernel weight was 64% in WLR and only 3% in modern material. Presence of positive allele of Sus2-2B increased 1000 kernel weight by nearly 4%. Breeding strategy to improved landraces and modern cultivars is discussed. Full article

Management strategies that integrate crops and livestock may lengthen the productivity of seasonal pasture systems in agroecological zones with short growing seasons. The biomass yield and nutritive value of fall-planted rye (Secale cereale L.) and wheat (Triticum aestivum L.) forages were determined in an integrated crop–livestock system under rotational cattle (Bos taurus L.) grazing and organic conditions for seven weeks during the spring and summer in Minnesota, USA. Rye yielded greater forage biomass at the beginning of the grazing interval, while wheat yielded greater forage biomass in the latter part of the grazing interval. In general, wheat had greater crude protein and less neutral detergent fiber, compared to rye, throughout the grazing interval. The predicted total tract neutral detergent fiber digestibility of forages was ≥50 g 100 g⁻¹ of neutral detergent fiber for at least the first four weeks of the grazing interval, indicating high forage digestibility in immature forages. Results from this study suggest that rye may provide more forage biomass for grazing earlier in the spring at the expense of lower nutritive quality, compared to wheat. Thus, the biomass yield and nutritional value of rye and wheat forages vary during the grazing interval, which informs producers of grazing schedule modifications in order to meet the nutritional demands of cattle. Full article

Viruses are microbes that have high economic impacts on the ecosystem. Widely spread by humans, plant viruses infect not only crops but also wild species. There is neither a cure nor a treatment against viruses. While chemists have developed further research of inefficient curative products, the relevant concept based on sanitary measures is consistently valuable. In this context, two major strategies remain indisputable. First, there are control measures via diagnostics presently addressing the valuable technologies and tools developed in the last four decades. Second, there is the relevant use of modern biotechnology to improve the competitiveness of fruit-tree growers. Full article

Cocoa is an important crop in Cameroon, where it is cultivated in different areas, including marginal areas, characterized by a rather low level of annual rainfall and marked dry seasons. In order to release cocoa varieties with a good level of adaptation to these marginal conditions, nine full-sib progenies, already released to farmers in other producing areas of the country, were assessed on twelve on farm cocoa plots, set up in 2006, in Mbam et Inoubou county, which is a forest–savannah transition zone. The traits assessed were mortality rate, yield and yield stability. Mortality rate and yield vary widely among trial plots and among progenies. Four out of the nine assessed progenies present a yield level significantly higher than the five others. The lowest level of yield stability (estimated by the contribution to total ecovalence) was observed in both the highest and the lowest yielding progenies. Recommendation for the large-scale release of these progenies to farmers of the county, and to other cocoa producing forest–savannah transition areas, are made, based on the results obtained from this study. Full article

The composition of apples varies with both cultivar and horticultural practice. Knowledge about the chemical composition of different cultivars in particular sugars, organic acids, nitrogen compounds and polyphenols is essential, since they are directly related to the progress of fermentation monitoring and the organoleptic qualities of produced ciders. Fifteen apple cultivars grown in two locations in Norway were investigated for their chemical composition, including polyphenol profiles. The nitrogen content varied from 43.2 to 171.4 mg N/L between the cultivars, and the sum of free amino acids varied from 42.4 to 924.5 mg/kg. Asparagine, aspartic acid and glutamic acid were the dominating amino acids. Flavanols, consisting of catechins and procyanidins, were the dominating polyphenols, followed by hydroxycinnamic acids. The cultivar Bramley Seedling was highest in the sum of polyphenols by HPLC (1838 mg/L) and relatively low in nitrogen content (75 mg N/L). Summerred was lowest in the sum of polyphenols (87 mg/L) and highest in nitrogen (171.4 mg N/L). Sugar content, measured as density in the juice, varied between 1034 and 1060 g/L. Using cider categorization of apples, ’Bramley Seedling’ would be defined as sharp, while the others are sweet cultivars. Full article

Halo blight, one of the major diseases of mungbean, is caused by the bacterium Pseudomonas savastanoi pv. phaseolicola. The pathogen infects the foliar parts of the plant, causing water-soaked spots that eventually develop surrounding yellow margins. The disease is particularly destructive under moderate temperature and high humidity, especially when it occurs during late vegetative through to early reproductive stage. In such conditions, severely infected crops could experience a yield loss up to 70%. Halo blight can be widespread on mungbeans grown in Southern Queensland and Northern New South Wales. However, due to its seedborne and cryptic nature of transmission, the disease is likely to be under-reported. This report addresses major aspects of halo blight symptomology, pathology and epidemiology. Full article