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Agronomy, Volume 8, Issue 6 (June 2018)

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Cover Story (view full-size image) To improve the effect of defoliation and reduce the losses caused by boom sprayer rolling, the [...] Read more.
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Open AccessArticle Long-Term Winter Wheat (Triticum aestivum L.) Seasonal Irrigation Amount, Evapotranspiration, Yield, and Water Productivity under Semiarid Climate
Received: 10 May 2018 / Revised: 14 June 2018 / Accepted: 16 June 2018 / Published: 16 June 2018
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Abstract
A long-term field experiment was conducted from 2002 to 2014 for the evaluation of yield and water productivity of three winter wheat varieties—Kharkof, Scout 66, and TAM107—under sprinkler irrigation at New Mexico State University Agricultural Science Center at Farmington, NM. Winter wheat daily
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A long-term field experiment was conducted from 2002 to 2014 for the evaluation of yield and water productivity of three winter wheat varieties—Kharkof, Scout 66, and TAM107—under sprinkler irrigation at New Mexico State University Agricultural Science Center at Farmington, NM. Winter wheat daily evapotranspiration was estimated following the United Nations Food and Agriculture Organization FAO crop coefficient approach (ETc = Kc ETo), and crop water use efficiency (CWUE), evapotranspiration water use efficiency (ETWUE), and irrigation water use efficiency (IWUE) were estimated for each growing season. There was inter-annual variation in seasonal precipitation and irrigation amounts. Seasonal irrigation amounts varied from 511 to 787 mm and the total water supply varied from 590 to 894 mm with precipitation representing a range of 7.7–24.2%. Winter wheat daily actual evapotranspiration (ETc) varied from 0.1 to 14.5 mm/day, averaging 2.7 mm/day during the winter wheat growing seasons, and the seasonal evapotranspiration varied from 625 to 890 mm. Grain yield was dependent on winter wheat variety, decreased with years, and varied from 1843.1 to 7085.7 kg/ha. TAM107 obtained the highest grain yield. Winter wheat CWUE, IWUE, and ETWUE were also varietal dependent and varied from 0.22 to 1.01 kg/m3, from 0.26 to 1.17 kg/m3, and from 0.29 to 0.92 kg/m3, respectively. CWUE linearly decreased with seasonal water, and IWUE linearly decreased with seasonal irrigation amount, while CWUE, IWUE, and ETWUE were positively correlated with the grain yield for the three winter wheat varieties, with R2 ≥ 0.85 for CWUE, R2 ≥ 0.69 for IWUE, and R2 ≥ 0.89 for ETWUE. The results of this study can serve as guidelines for winter wheat production in the semiarid Four Corners regions. Additional research need to be conducted for optimizing winter wheat irrigation management relative to planting date and fertilization management to reduce the yield gap between winter wheat actual yield and the national average yield. Full article
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Open AccessArticle Genetic Diversity of Clinal Freezing Tolerance Variation in Winter Wheat Landraces
Received: 6 May 2018 / Revised: 9 June 2018 / Accepted: 12 June 2018 / Published: 14 June 2018
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Abstract
Wheat (Triticumaestivum L.) is a major cereal crop grown across a wide range of environments, but its productivity around the world is challenged by various biotic and abiotic factors. Wheat landraces from around the world are a source of unexploited genetic
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Wheat (Triticumaestivum L.) is a major cereal crop grown across a wide range of environments, but its productivity around the world is challenged by various biotic and abiotic factors. Wheat landraces from around the world are a source of unexploited genetic diversity that can be essential for modern wheat-breeding programs in search of resistance to abiotic stresses like freezing tolerance. This genetic diversity study of 553 winter wheat landraces based on single-nucleotide polymorphisms (SNPs) revealed separate clusters of landraces related to the latitude of origin. Linkage block analysis revealed genomic regions with specific alleles skewed towards landraces from higher latitudes, suggesting that migration to higher latitudes resulted in the fixing of specific alleles. Electrolyte leakage was used to measure the tolerance of freezing to −14 °C, −16 °C, and −18 °C of 192 landraces. There was a significant negative correlation between latitude and electrolyte leakage, with an R2 value of 0.14, (p < 0.0001), in a regression analysis indicating greater freezing tolerance in landraces from higher latitudes. Genome-wide association studies identified regions in chromosomes 4A and 6A associated with higher latitudes and freezing tolerance, respectively. Landraces with freezing tolerance may be useful in developing new germplasm as novel sources of greater cold hardiness. Full article
(This article belongs to the Special Issue Quantitative Trait Locus Mapping for Crop Plants)
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Open AccessArticle Dissecting Wheat Grain Yield Drivers in a Mapping Population in the UK
Received: 31 March 2018 / Revised: 1 June 2018 / Accepted: 12 June 2018 / Published: 14 June 2018
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Abstract
Improving crop yields arises as a solution to ensure food security in the future scenarios of a growing world population, changes in food consumption patterns, climate change, and limitations on resources allocated to agriculture. Defining traits that can be reliable cornerstones to yield
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Improving crop yields arises as a solution to ensure food security in the future scenarios of a growing world population, changes in food consumption patterns, climate change, and limitations on resources allocated to agriculture. Defining traits that can be reliable cornerstones to yield improvement and understanding of their interaction and influence on yield formation is an important part of ensuring the success of breeding programs for high yields. Traits that can drive yield increases, such as light interception and conversion efficiency, as well as carbon assimilation and allocation, were intensively phenotyped in a double-haploid wheat mapping population grown under field conditions in the UK. Traits were analysed for their correlation to yield, genetic variation, and broad-sense heritability. Canopy cover and reflectance, biomass production, and allocation to stems and leaves, as well as flag leaf photosynthesis at a range of light levels measured pre- and post-anthesis correlated with plant productivity and contributed to explaining different strategies of wheat lines to attain high grain yields. This research mapped multiple traits related to light conversion into biomass. The findings highlight the need to phenotype traits throughout the growing season and support the approach of targeting photosynthesis and its components as traits for breeding high yielding wheat. Full article
(This article belongs to the Special Issue Photosynthetic Carbon Metabolism to Enhance Crop Productivity)
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Open AccessArticle Production of a Polyclonal Antibody against the Recombinant Coat Protein of the Sugarcane Mosaic Virus and Its Application in the Immunodiagnostic of Sugarcane
Received: 3 May 2018 / Revised: 3 June 2018 / Accepted: 11 June 2018 / Published: 13 June 2018
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Abstract
Sugarcane mosaic virus (SCMV) is a mosaic disease that has spread over sugarcane plantations in Indonesia. The important step to overcome the disease is to detect the pathogen as early as possible. Detection of the pathogen can be achieved using the immunodiagnostic method
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Sugarcane mosaic virus (SCMV) is a mosaic disease that has spread over sugarcane plantations in Indonesia. The important step to overcome the disease is to detect the pathogen as early as possible. Detection of the pathogen can be achieved using the immunodiagnostic method by employing a specific antibody against the viral coat protein. The objective of this research was to produce a polyclonal antibody using the recombinant coat protein of SCMV, and to test its sensitivity for detection of SCMV in the symptomatic plant. The gene encoding of the coat protein was cloned using the RT-PCR Kit and total RNA isolated from symptomatic sugarcane leaves cultivar PS-881. Nucleotide sequences analysis of the cloned cDNA indicated that the cDNA contained 998 nucleotides and named SCMVCp-cDNA. The cDNA was then inserted into a His-tag expression plasmid of pET28a and overexpressed in Escherichia coli BL21 (DE3) to produce a recombinant protein. The recombinant fused protein SCMVCp was strongly expressed in an insoluble fraction, with a molecular size of around 44 kDa, without the addition of an IPTG inducer. Purification of the recombinant protein using an affinity Ni-NTA resin, followed by SDS-PAGE separation, resulted in a high purity of the protein and used as an antigen to raise the polyclonal antibody in a rabbit. The sensitivity of the antiserum determined by western blot analysis showed that the antiserum was able to detect the recombinant protein at a concentration of 10 ng. The western blot analysis also detected a clear single band of 36.7 kDa of the SCMV coat protein in symptomatic sugarcane leaves and not in healthy leaves. Interestingly, when the sample proteins were prepared using low-speed centrifugation, the corresponding coat protein was detected in a soluble fraction by western blot analysis. Thus, the antiserum was successfully used for indirect-ELISA analysis using the soluble protein fraction. The results provide an easy method to detect and diagnose SCMV infection using the immunodiagnostic. Full article
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Open AccessCommunication Effect of Olive-Mill Wastewater Application, Organo-Mineral Fertilization, and Transplanting Date on the Control of Phelipanche ramosa in Open-Field Processing Tomato Crops
Received: 13 May 2018 / Revised: 14 May 2018 / Accepted: 7 June 2018 / Published: 11 June 2018
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Abstract
Phelipanche ramosa (L) Pomel is a root holoparasitic weed for many crops, particularly for the processing tomato in Italy. In order to integrate the use of chemical methods to control P. ramosa (L.), there has been an increased effort to research alternative methods
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Phelipanche ramosa (L) Pomel is a root holoparasitic weed for many crops, particularly for the processing tomato in Italy. In order to integrate the use of chemical methods to control P. ramosa (L.), there has been an increased effort to research alternative methods using natural compounds. In this regard, two experimental trials were set up in an open field in Foggia (southern Italy) during the 2016 spring–summer seasons. The first trial compared two tomato seedling transplanting dates to evaluate the effects on emerged shoots of P. ramosa. The second trial compared six organic compounds added to the soil to control P. ramosa: olive-mill wastewater and five commercial products (Allyl Isothiocyanate®, Alfaplus®, Radicon®, Rhizosum Max®, and Kendal Nem®). An untreated control was also included. The numbers of P. ramosa emerged shoots (branched plants) were significantly lower for the late tomato seedling transplanting date than for the earlier one. All of the organic products tested that were applied to the soil, particularly olive-mill wastewater, Alfaplus®, Rhizosum Max®, and Kendal Nem®, showed a significant reduction of the P. ramosa infestation of the tomato crop with respect to the untreated control, with a positive effect on the productive parameters. Full article
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Open AccessArticle Image-Based On-Panicle Rice [Oryza sativa L.] Grain Counting with a Prior Edge Wavelet Correction Model
Received: 28 February 2018 / Revised: 22 April 2018 / Accepted: 16 May 2018 / Published: 7 June 2018
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Abstract
The number of rice grains on a panicle is an important index for variety screening during high-quality rice [Oryza Sativa L.] breeding. For an in-vivo image-based measurement, the occlusion and overlapping among grains are the major challenges in non-destructive precise phenotyping of
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The number of rice grains on a panicle is an important index for variety screening during high-quality rice [Oryza Sativa L.] breeding. For an in-vivo image-based measurement, the occlusion and overlapping among grains are the major challenges in non-destructive precise phenotyping of the on-panicle grains. In order to tackle these challenges, this paper describes a correction-model-referred on-panicle grain counting method based on the area of the rice panicle and its edge contour wavelet analysis. First, we assume that a deterministic correlation exists between the number of grains of the panicle and the traits of its edge contour morphology, which reflects the extent to which the grains are occluded. Second, a method for coarsely estimating grain number per panicle is proposed based on the projective area of the panicle in the image and the average area of a rice grain. Finally, a correction model which is built with the average wavelet frequency of the edge contour of the panicle is employed to correct the estimated value of the grain number. Two randomly selected cases are investigated in detail, showing that computation accuracy with a correction model is increased by 26% and 23% respectively when compared to that of the naive area-based computation. In conclusion, we reveal and validate the relationship between the number of grains of the panicle and the fluctuation frequency of its edge contours. Further, experiments show that errors caused by overlapping and occlusion scenarios can be alleviated with the estimation and correction hybrid models, achieving an average accuracy of 94% compared to the results of manual counting. Full article
(This article belongs to the Special Issue Precision Phenotyping in Plant Breeding)
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Open AccessArticle Seed Yield and Water Productivity of Irrigated Winter Canola (Brassica napus L.) under Semiarid Climate and High Elevation
Received: 17 April 2018 / Revised: 26 May 2018 / Accepted: 5 June 2018 / Published: 6 June 2018
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Abstract
Canola is a cash crop produced for its highly-valued seed, and as a protein source for animal feed. While winter canola is produced mainly in the high plains, it is expanding to new environments, and is greatly incorporated into crop systems with advantages
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Canola is a cash crop produced for its highly-valued seed, and as a protein source for animal feed. While winter canola is produced mainly in the high plains, it is expanding to new environments, and is greatly incorporated into crop systems with advantages in terms of increasing crop yield and improving soil health. The objectives of this study were to evaluate eight winter canola genotypes for seed yield, and to determine their water productivity under semiarid climates and high elevations in the Four Corners region at Farmington, New Mexico. A field experiment was conducted at the New Mexico State Agricultural Science Center at Farmington for five growing seasons. Eight genotypes of winter canola (Baldur, Flash, Safran, Sitro, Virginia, Visby, Wichita, and Sumner) were arranged into the randomized complete block design. The field was fully irrigated with a center pivot irrigation system. Results showed that winter canola seed yield was dependent on genotype, varying from 2393 to 5717 kg/ha. The highest yield was achieved by Sitro, and the lowest yield by Sumner. There was inter-annual variation in canola nitrogen-use efficiency (NUE), irrigation water-use efficiency (IWUE), and crop water-use efficiency (CWUE). NUE varied from 12.9 to 50.4 kg seed/kg N, with the highest NUE achieved by Sitro, and the lowest by Sumner. IWUE varied from 0.34 to 0.80 kg/m3, and canola CWUE from 0.28 to 0.69 kg/m3. The highest water productivity was achieved by Sitro. The results of this study showed full assessment of canola production under the semiarid climate in the Four Corners region, and could improve crop productivity and profitability. Full article
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Open AccessArticle Olive Water Use, Crop Coefficient, Yield, and Water Productivity under Two Deficit Irrigation Strategies
Received: 10 May 2018 / Revised: 23 May 2018 / Accepted: 1 June 2018 / Published: 3 June 2018
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Abstract
Reports on the annual effects of deficit irrigation regimes on olive trees are critical in shedding light on their impacts on water use, yield, and water productivity in distinct olive growing climate regions of the world. From the account of a four-year experiment,
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Reports on the annual effects of deficit irrigation regimes on olive trees are critical in shedding light on their impacts on water use, yield, and water productivity in distinct olive growing climate regions of the world. From the account of a four-year experiment, the aim of this work is to add insight into such effects on olive growing in southern Portugal. We worked with trees in an intensive ‘Cobrançosa’ orchard (300 trees ha−1) under full irrigation (FI) treatment and two regulated deficit irrigation (DI) treatments designed to replace around 70% and 50% of the FI water supply, respectively. Crop transpiration (T), irrigation water use (IWU), total water use (TWU), irrigation water use efficiency (IWUE), yield (Ya), and water productivity (WP) obtained from all treatments were analyzed, as well as their crop coefficients (Kc), simulated with the SIMDualKc software application for root zone and soil water balance based on the FAO dual crop coefficients. As expected, IWUE of the 50DI treatment was the highest among treatments, with 70DI being slightly lower. Ya showed alternate bearing with an “on-off” year sequence and was consistently higher for the 70DI treatment. WP (the ratio of Ya to IWU) values for the 70DI treatment were also consistently the highest among all treatments and years. The mean simulated Kc act values for 70DI and 50DI for the initial, mid-, and end-season compared well to the FAO56 Kc for olive crops. In general, to rank the irrigation treatments, 70DI presented the highest conversion efficiency among all treatments and years, providing a suitable DI alternative for our ‘Cobrançosa’ orchard. The 50DI treatment may be an attractive DI regime to undertake under scarce farm water resources or the expansion of olive hectares under water constraints. Full article
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Open AccessArticle Biomass Production and Composition of Temperate and Tropical Maize in Central Iowa
Received: 18 April 2018 / Revised: 23 May 2018 / Accepted: 28 May 2018 / Published: 1 June 2018
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Abstract
Bioethanol production in the midwestern U.S. has largely focused on maize (Zea mays L.) grain for starch-based ethanol production. There has been growing interest in lignocellulosic biomass as a feedstock for biofuels. Because maize adapted to the tropics does not initiate senescence
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Bioethanol production in the midwestern U.S. has largely focused on maize (Zea mays L.) grain for starch-based ethanol production. There has been growing interest in lignocellulosic biomass as a feedstock for biofuels. Because maize adapted to the tropics does not initiate senescence as early as temperate-adapted maize, using a tropical germplasm could improve biomass yield. This study compares the suitability of temperate and tropical maize with differing relative maturities as feedstocks for bioethanol production. Field trials were established in central Iowa during the 2014 and 2015 growing seasons. Six hybrids of different relative maturities were grown at two levels of N fertilization and two row spacings to evaluate total biomass production and feedstock quality under midwestern U.S. conditions. Total biomass, height at the final leaf collar, stem diameter at one meter above ground, and lignocellulose concentration were measured at harvest. Tropical maize was taller and had greater non-grain and total biomass production (15% more than temperate maize), while temperate maize had greater grain yield and grain starch, as well as earlier maturation. Narrower row spacing had greater biomass and grain yield. Nitrogen fertilization rate affected grain and feedstock composition. Tropical maize had lower cellulose, lignin, and ash concentrations and higher nitrogen at harvest than that of temperate maize. Conversely, temperate maize had greater ash, cellulose, and lignin concentrations. Tropical maize planted at high densities has high potential as a feedstock for bioethanol production in the U.S. Midwest. Full article
(This article belongs to the Special Issue Forage and Bioenergy Crops)
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Open AccessArticle The Effect of Barley Cover Crop Residue and Herbicide Management on the Foliar Arthropod Community in No-Till Soybeans
Received: 10 May 2018 / Revised: 11 May 2018 / Accepted: 30 May 2018 / Published: 1 June 2018
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Abstract
Cover cropping has long been used as a method of reducing soil erosion, increasing soil quality, and suppressing weeds. However, the effects of cover crops in local farming systems are varied and can be affected by timing and method of termination. Field experiments
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Cover cropping has long been used as a method of reducing soil erosion, increasing soil quality, and suppressing weeds. However, the effects of cover crops in local farming systems are varied and can be affected by timing and method of termination. Field experiments were conducted at two sites in Maryland, USA during the 2013 and 2014 growing seasons to examine how varying the date and method of terminating a barley (Hordeum vulgare) cover crop affects the arthropod communities in succeeding no-till soybean (Glycine max). Experimental treatments included early-kill with pre- and post-emergent herbicides (EK), late-kill with pre- and post-emergent herbicides (LK), late-kill with a flail mower and pre-emergent herbicide (FM), and a fallow/bare-ground check with pre- and post-emergent herbicides (BG). Terminating barley late, just prior to soybean planting, resulted in significantly greater biomass accumulation in LK and FM than EK. However, method and timing of termination had no effect on the community of pest and beneficial arthropods in the soybean canopy. Results from this experiment suggest that terminating the cover crop early or late (just prior to crop planting) or using a mower or post-emergent herbicide will result in a similar community of arthropods within the soybean canopy. Full article
(This article belongs to the Special Issue Pest Management in Agroecosystems)
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Open AccessArticle Water-Stressed Loquat Trees Need More Time and Heat to Ripen Their Fruits
Received: 23 April 2018 / Revised: 26 May 2018 / Accepted: 30 May 2018 / Published: 1 June 2018
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Abstract
To determine if water-stressed trees need more time and heat to mature their fruits, we compared chronological and thermal time from bloom to harvest among control fully-irrigated ‘Algerie’ loquat trees and trees suffering prior-to-bloom deficit irrigation (DI). Heat requirement calculation was performed using
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To determine if water-stressed trees need more time and heat to mature their fruits, we compared chronological and thermal time from bloom to harvest among control fully-irrigated ‘Algerie’ loquat trees and trees suffering prior-to-bloom deficit irrigation (DI). Heat requirement calculation was performed using the double sine method with a lower threshold temperature of 3 °C. The results show that the greater the blooming advancement achieved by DI, the longer the period to mature the fruits. Such a pattern indicates that the longer duration for bloom-harvest period under DI is due to a displacement of the reproductive phenology to cooler dates. However, some effects of DI on heat requirements for ripening persist, indicating a slower fruit development in some, but not all, DI treatments. The differences in fruit development rate between fully-irrigated and water-stressed trees were established during the phase of rapid fruit growth. The comparison of water stress effects on sink (flower size and seed number) and source (leaf number and size, gas exchange and mineral and carbohydrate nutrition) of DI treatments seems to indicate that the amount of stored reserves in the leaves to sustain early fruit development is the most plausible reason behind the increase in thermal time between bloom and harvest in water-stressed loquats. Full article
(This article belongs to the Special Issue Sustainable Agriculture and Water Footprint)
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Open AccessArticle Effects of Dosage and Spraying Volume on Cotton Defoliants Efficacy: A Case Study Based on Application of Unmanned Aerial Vehicles
Received: 28 March 2018 / Revised: 9 May 2018 / Accepted: 18 May 2018 / Published: 30 May 2018
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Abstract
Plant protection unmanned aerial vehicles (UAVs) consist of light and small UAVs with pesticide spraying equipment. The advantage of UAVs is using low-volume spray technology to replace the traditional large-volume mass locomotive spray technology. Defoliant spraying is a key link in the mechanized
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Plant protection unmanned aerial vehicles (UAVs) consist of light and small UAVs with pesticide spraying equipment. The advantage of UAVs is using low-volume spray technology to replace the traditional large-volume mass locomotive spray technology. Defoliant spraying is a key link in the mechanized cotton harvest, as sufficient and uniform spraying can improve the defoliation quality and decrease the cotton trash content. However, cotton is planted at high density in Xinjiang, with leaves in two adjacent rows seriously overlapped, making the lower leaves poorly sprayed. Thus, the defoliation effect is poor, and the cotton quality is degraded. To improve the effect of defoliation and reduce the losses caused by boom sprayer rolling, the effect of defoliant dosage on defoliation, boll opening, absorption and decontamination in cotton leaves and the effect of spraying volume on absorption and decontamination in cotton leaves sprayed by UAVs are studied. The pooled results indicate that plant protection UAVs could be used for cotton defoliants spraying with a twice defoliant spraying strategy, and the defoliant dosage has no significant effect on seed cotton yield and fiber quality in Xinjiang. The residue of thidiazuron in cotton leaves reaches the maximum at four days after spraying, the residue of diuron in cotton leaves reaches the maximum at one day after second spraying. The thidiazuron and diuron residues are increased with spraying volume at rang of 17.6–29.0 L/ha. When the spraying volume is less than 17.6 L/ha, the residue of thidiazuron and diuron is reduced. The research results could provide a reference for further optimization of the spraying parameters of cotton defoliant by plant protection UAVs. Full article
(This article belongs to the Special Issue Sensing and Automated Systems for Improved Crop Management)
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Open AccessReview Breeding Maize for Tolerance to Acidic Soils: A Review
Received: 31 March 2018 / Revised: 21 May 2018 / Accepted: 23 May 2018 / Published: 29 May 2018
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Abstract
Acidic soils hamper maize (Zea mays L.) production, causing yield losses of up to 69%. Low pH acidic soils can lead to aluminum (Al), manganese (Mn), or iron (Fe) toxicities. Genetic variability for tolerance to low soil pH exists among maize genotypes,
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Acidic soils hamper maize (Zea mays L.) production, causing yield losses of up to 69%. Low pH acidic soils can lead to aluminum (Al), manganese (Mn), or iron (Fe) toxicities. Genetic variability for tolerance to low soil pH exists among maize genotypes, which can be exploited in developing high-yielding acid-tolerant maize genotypes. In this paper, we review some of the most recent applications of conventional and molecular breeding approaches for improving maize yield under acidic soils. The gaps in breeding maize for tolerance to low soil pH are highlighted and an emphasis is placed on promoting the adoption of the numerous existing acid soil-tolerant genotypes. While progress has been made in breeding for tolerance to Al toxicity, little has been done on Mn and Fe toxicities. More research inputs are therefore required in: (1) developing screening methods for tolerance to manganese and iron toxicities; (2) elucidating the mechanisms of maize tolerance to Mn and Fe toxicities; and, (3) identifying the quantitative trait loci (QTL) responsible for Mn and Fe tolerance in maize cultivars. There is also a need to raise farmers’ and other stakeholders’ awareness of the problem of Al, Mn, and Fe soil toxicities to improve the adoption rate of the available acid-tolerant maize genotypes. Maize breeders should work more closely with farmers at the early stages of the release process of a new variety to facilitate its adoption level. Researchers are encouraged to strengthen their collaboration and exchange low soil pH-tolerant maize germplasm. Full article
(This article belongs to the Special Issue Environmental and Management Factor Contributions to Maize Yield)
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Open AccessReview Physiological and Agronomic Strategies to Increase Mungbean Yield in Climatically Variable Environments of Northern Australia
Received: 4 May 2018 / Revised: 23 May 2018 / Accepted: 24 May 2018 / Published: 26 May 2018
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Abstract
Mungbean (Vigna radiata (L.) Wilczek) in Australia has been transformed from a niche opportunistic crop into a major summer cropping option for dryland growers in the summer-dominant rainfall regions of Queensland and New South Wales. This transformation followed stepwise genetic improvements in
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Mungbean (Vigna radiata (L.) Wilczek) in Australia has been transformed from a niche opportunistic crop into a major summer cropping option for dryland growers in the summer-dominant rainfall regions of Queensland and New South Wales. This transformation followed stepwise genetic improvements in both grain yields and disease resistance. For example, more recent cultivars such as ‘Crystal’, ‘Satin II’, and ‘Jade-AU‘ have provided up to a 20% yield advantage over initial introductions. Improved agronomic management to enable mechanised management and cultivation in narrow (<50 cm) rows has further promised to increase yields. Nevertheless, average yields achieved by growers for their mungbean crops remain less than 1 t/ha, and are much more variable than other broad acre crops. Further increases in yield and crop resilience in mungbean are vital. In this review, opportunities to improve mungbean productivity have been analysed at four key levels including phenology, leaf area development, dry matter accumulation, and its partitioning into grain yield. Improving the prediction of phenology in mungbean may provide further scope for genetic improvements that better match crop duration to the characteristics of target environments. There is also scope to improve grain yields by increasing dry matter production through the development of more efficient leaf canopies. This may introduce additional production risks as dry matter production depends on the amount of available water, which varies considerably within and across growing regions in Australia. Improving crop yields by exploiting G × E × M interactions related to cultivar photo-thermal sensitivities and make better use of available water in these variable environments is likely to be a less risky strategy. Improved characterisation of growing environments using modelling approaches could also better define and identify the risks of major abiotic constraints. This would assist in optimising breeding and management strategies to increase grain yield and crop resilience in mungbean for the benefit of growers and the industry. Full article
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Open AccessFeature PaperArticle “Alperujo” Compost Improves the Ascorbate (Vitamin C) Content in Pepper (Capsicum annuum L.) Fruits and Influences Their Oxidative Metabolism
Received: 19 April 2018 / Revised: 17 May 2018 / Accepted: 23 May 2018 / Published: 25 May 2018
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Abstract
“Alperujo” compost was evaluated as an organic fertiliser for pepper growth under greenhouse conditions. Even though the total nitrogen applied was similar, plants only grown with composts experienced a development decline as compared to those grown with standard nutrient solution. This was perhaps
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“Alperujo” compost was evaluated as an organic fertiliser for pepper growth under greenhouse conditions. Even though the total nitrogen applied was similar, plants only grown with composts experienced a development decline as compared to those grown with standard nutrient solution. This was perhaps because nitrogen from the compost was essentially organic, and not easily available for roots. When, alternatively, the compost was supplemented with nitrate, a synergetic effect was observed, favouring plant development and fruit yield, simultaneously with the increase of compost rates. Compost affected the oxidative metabolism of pepper plants by increasing their antioxidative enzyme activities catalase and superoxide dismutases and the non-enzymatic antioxidants ascorbate and glutathione. Overall, when nitrogen limitation occurred and only compost was used as fertiliser, an oxidative stress took place, whereas in plants grown with nitrate-supplemented compost it did not. Furthermore, these pepper plants experienced a yield increase and, more importantly, an enhancement of the ascorbate content. Full article
(This article belongs to the Special Issue Further Metabolism in Plant System)
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Open AccessEditorial Starch Biosynthesis in Crop Plants
Received: 8 May 2018 / Revised: 21 May 2018 / Accepted: 22 May 2018 / Published: 25 May 2018
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Starch is a water-insoluble polyglucan synthesized inside the plastids of plant tissues to provide a store of carbohydrate. Starch harvested from plant storage organs has probably represented the major source of calories for the human diet since before the dawn of civilization. Following
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Starch is a water-insoluble polyglucan synthesized inside the plastids of plant tissues to provide a store of carbohydrate. Starch harvested from plant storage organs has probably represented the major source of calories for the human diet since before the dawn of civilization. Following the advent of agriculture and the building of complex societies, humans have maintained their dependence on high-yielding domesticated starch-forming crops such as cereals to meet food demands, livestock production, and many non-food applications. The top three crops in terms of acreage are cereals, grown primarily for the harvestable storage starch in the endosperm, although many starchy tuberous crops also provide an important source of calories for various communities around the world. Despite conservation in the core structure of the starch granule, starches from different botanical sources show a high degree of variability, which is exploited in many food and non-food applications. Understanding the factors underpinning starch production and its final structure are of critical importance in guiding future crop improvement endeavours. This special issue contains reviews on these topics and is intended to be a useful resource for researchers involved in improvement of starch-storing crops. Full article
(This article belongs to the Special Issue Starch Biosynthesis in Crop Plants)
Open AccessArticle Linkage Map of a Gene Controlling Zero Tannins (zt-1) in Faba Bean (Vicia faba L.) with SSR and ISSR Markers
Received: 4 April 2018 / Revised: 18 May 2018 / Accepted: 18 May 2018 / Published: 23 May 2018
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Abstract
Faba bean (Vicia faba L.), a partially allogamous species, is rich in protein. Condensed tannins limit the use of faba beans as food and feed. Two recessive genes, zt-1 and zt-2, control the zero tannin content in faba bean and promote
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Faba bean (Vicia faba L.), a partially allogamous species, is rich in protein. Condensed tannins limit the use of faba beans as food and feed. Two recessive genes, zt-1 and zt-2, control the zero tannin content in faba bean and promote a white flower phenotype. To determine the inheritance and develop a linkage map for the zt-1 gene in the faba bean germplasm M3290, F2 and F3 progenies were derived from the purple flower and high tannin content genotypes Qinghai12 and zt-1 line M3290, respectively. Genetic analysis verified a single recessive gene for zero tannin content and flower colour. In total, 596 SSR markers and 100 ISSR markers were used to test the polymorphisms between the parents and bulks for the contrasting flower colour via Bulked Segregant Analysis (BSA). Subsequently, six SSR markers and seven ISSR markers were used to genotype the entire 413 F2 population. Linkage analysis showed that the zt-1 gene was closely linked to the SSR markers SSR84 and M78, with genetic distances of 2.9 and 5.8 cM, respectively. The two flanked SSR markers were used to test 34 faba bean genotypes with different flower colours. The closely linked SSR marker SSR84 predicted the zt-1 genotypes with absolute accuracy. The results from the marker-assisted selection (MAS) from this study could provide a solid foundation for further faba bean breeding programmes. Full article
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Open AccessArticle Agrobiodiversity for Adaptive and Yield Traits in Romanian and Italian Barley Cultivars across Four Continental Environments
Received: 2 May 2018 / Revised: 14 May 2018 / Accepted: 16 May 2018 / Published: 23 May 2018
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Abstract
Within temperate climates the frequency and severity of high and low temperature stresses vary with continentality. The current study reports on the assessment of the performance of 49 barley cultivars across four environments. The cultivars stem from 50 years of breeding activities in
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Within temperate climates the frequency and severity of high and low temperature stresses vary with continentality. The current study reports on the assessment of the performance of 49 barley cultivars across four environments. The cultivars stem from 50 years of breeding activities in Romania and Italy, in two temperate climates that differ in continentality. The plants were phenotyped through stress monitoring, measurements of yield and yield related traits as well as laboratory stress tolerance tests. Genotypes for alleles of vernalisation and photoperiod genes were determined. These genes were significantly associated with frost damage in the field and frost tolerance in laboratory tests. Grain yield (GY) was more closely correlated with the number of grain sinks than with the degree of grain filling indicating major limitations in the vegetative growth phase and during grain initiation. High temperature stress during the grain filling phase significantly reduced GY. Frost damage due to freezing temperatures below −10 °C when plants were not protected by snow cover significantly reduced GY of sensitive cultivars. The characterisation of environmental cues that cause stresses with yield penalties as well as the susceptibility of genetically different cultivars lay the ground for future targeted selection. Full article
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