Soft Red Winter Research Articles

Phenotypic and genetic analysis to identify secondary physiological traits for improving grain yield in wheat considering anthesis time variability

Identification of secondary traits in mapping populations is usually hindered by the strong effect of anthesis time. Thus, considering the variability in time to anthesis in combination with an accurate phenotyping of mapping populations and available molecular tools is a possible way for recognising secondary traits to improve yield potential. The aim of this work was to identify secondary traits to perform indirect selection for grain yield (GY) in a bread wheat mapping population consisting of 124 doubled haploid lines, derived from the cross between two soft red winter wheat genotypes with contrasting photoperiod response. Genomic regions linked to different traits were analysed under two environments. The population showed a strong effect of time to anthesis over GY, as expected. A large variability in GY was observed but only two QTLs were detected on chromosome 5A for this trait, which co-localized with QTLs of time to anthesis. GY variation was partially associated with above-ground dry matter at maturity (AGDM) and to a lesser extent with harvest index (HI). Detected QTLs for grains per m2 (GN), grain weight, AGDM and HI explained between 25 and 61% of the GY additive genetic variance. GN, defined as the product between spike dry weight at anthesis (SDW) and fruiting efficiency (FE), was the main numerical component that explained most of the variation in GY. Five QTLs were detected for SDW, which did not co-localize with QTLs of time to anthesis and captured ca. 50% of the additive genetic variance, while there was a weak relationship between NG and FE. When genotypes were filtered by similar anthesis time and plant height, SDW was identified as a promising secondary trait to be targeted for indirect selection of GY.

Greater Biomass Accumulation at Anthesis Increases Nitrogen Use Efficiency in Winter Wheat

Soft red winter wheat (Triticum aestivum L.) production relies on efficient nitrogen (N) fertilization to maximize grower profitability and mitigate environmental impacts. Therefore, a panel of 11 elite wheat lines were grown as a randomized complete block design in four environments under low (LN) and high (HN) N rates to: (i) assess the genotypic variation in aboveground biomass (AGBM) and N yield (AGNY) throughout the growing season; and (ii) investigate the associations between yield and N‐related traits with AGBM and AGNY at tillering, booting, anthesis, and physiological maturity. Biomass samples were cut at the soil level and dried at four developmental stages to determine AGBM then ground to estimate AGNY for each sample. Significant genotypic variation (P ≤ 0.05) was observed for grain yield, grain N content, and N‐utilization efficiency in all testing environments. Additionally, significant (P ≤ 0.05) variation for AGBM and AGNY was identified at the five‐tiller stage, booting, anthesis, and physiological maturity in one or more testing environments. Grain yield was not significantly correlated with any trait under LN conditions despite expressing significant association with N‐utilization efficiency, N‐harvest index, AGBM at anthesis, and AGNY at anthesis under HN rates. Significant correlations also were identified for traits between LN and HN rates including AGBM at anthesis (r = 0.93, P < 0.001) and AGNY (r = 0.69, P < 0.01). Our results suggest that breeders can improve grain yields by using AGBM at anthesis as a proxy trait.Core Ideas Genotypic variation was observed in grain yield and N content, N‐utilization, biomass, and N yield. Grain yield correlated with aboveground biomass and aboveground N yield at anthesis under high N rates. Breeders can improve yields by using biomass at anthesis as a proxy trait per its strong correlation with N rates.

Yield Data from the Uniform Southern Soft Red Winter Wheat Nursery Emphasize Importance of Selection Location and Environment for Cultivar Development

Yield and agronomic data from a regional soft red winter wheat (Triticum aestivum L.) nursery—consisting of 604 advanced breeding lines (ABLs) and 36 testing locations over a 21‐yr period—were evaluated to understand recent genetic gains in wheat and determine the impact of selection location and environment on cultivar performance and adaptation. Relative mean yield improvement of ABLs with respect to historical cultivar AGS 2000 was 106 kg ha−1 yr−1 (1.58 bu acre−1 yr−1), equating to an annual genetic gain of 1.6%. Yield gains for wheat during this timespan were attributed to an increase in both yield potential and stability across environments. However, a strong tradeoff (r = −0.36, p < 2.2 × 10−16) was observed between yield potential and stability. Additionally, distance between selection and evaluation environments was significantly correlated with yield, with yield decreasing as distance between locations increased. Advanced breeding lines had a +221, +126, and −29.6 kg ha−1 yr−1 (+3.29, +1.88, and −0.44 bu acre−1) yield difference over the location mean when the selection location was within, adjacent, and nonadjacent to the trial location zone, respectively. Advanced breeding lines in general performed poorly in production environments west of their selection site. Based on data analyzed, elevation and latitude are significant geographic parameters to consider when determining optimal selection location for a production environment. Meanwhile, change in growing degree days between selection and evaluation location had a stronger influence on yield than precipitation. Findings demonstrate the importance and benefits of breeder collaborations and multienvironment testing on crop improvement, which will be needed to maximize yield gains in the 21st century.

GWAS for Fusarium Head Blight Traits in a Soft Red Winter Wheat Mapping Panel

Fusarium head blight (FHB) is an important disease of wheat (Triticum aestivum L.) that has caused billions of dollars in losses in recent decades. Although a massive breeding effort has been undertaken on multiple continents, there are no wheat cultivars with immunity to the disease. Resistance is conditioned by multiple loci and is further complicated by the role of the environment in expression of the disease phenotype. The objectives of our study were (i) to evaluate the phenotypic response to FHB in a large, diverse soft red winter wheat mapping panel; and (ii) to identify promising quantitative trait loci (QTL) associated with FHB resistance based on a genome‐wide association study (GWAS). We evaluated the mapping panel in 2014–2015 and 2015–2016 in an irrigated, inoculated scab nursery near Lexington, KY. Traits evaluated were heading date, plant height, FHB rating, severity, incidence, index, Fusarium‐damaged kernels (FDK), and deoxynivalenol (DON). There were significant (p < 0.05) differences among genotypes for all traits measured. The GWAS (based on 2‐yr entry means) identified 16 significant (p < 0.001) single nucleotide polymorphisms (SNPs) associated with disease traits on multiple chromosomes. Single nucleotide polymorphism association ranged from −2.14 to 4.01% of the mean of a given trait. We detected SNPs associated with FDK and DON on chromosomes 4A, 5B and 6B, and these SNPs decreased DON levels by 1.5, 2.1 and 3.2 mg kg−1, respectively. Our study demonstrated that even small‐effect QTL can potentially decrease disease levels and thus be useful in breeding programs.

Virulence of Puccinia triticina, the Wheat Leaf Rust Fungus, in the United States in 2017.

Samples of wheat leaves infected with the leaf rust fungus, Puccinia triticina, were obtained in 2017 from agricultural experiment station plots, demonstration plots, and farm fields in the Great Plains, the Ohio Valley, the southeastern states, California, and Washington in order to determine the prevalent virulence phenotypes present in the United States. A total of 65 virulence phenotypes were identified among the 469 single uredinial isolates that were tested on 20 near-isogenic lines of Thatcher wheat that differ for leaf rust resistance genes. Virulence phenotypes MBTNB at 11.3% of the overall population, and MCTNB at 7.0%, were the first and third most common phenotypes. Both phenotypes were found mostly in the southeastern states and Ohio Valley region. Phenotype TFTSB at 10.9% was the second most common phenotype and was found mostly in southern Texas. Virulence to leaf rust resistance gene Lr39, which is present in hard red winter wheat cultivars, was highest in the Great Plains region. Virulence to Lr11 and Lr18, which are present in soft red winter wheat cultivars, was highest in the southeastern states and Ohio Valley region. Virulence to Lr21, which is present in hard red spring wheat cultivars, was highest in the northern Great Plains region. The predominate P. triticina phenotypes from the soft red winter wheat regions of the southeastern states and Ohio Valley area differed from those in the hard red winter and hard red spring wheat areas of the Great Plains region. Collections from Washington had unique virulence phenotypes that had not been previously detected.

Association Analysis of Baking and Milling Quality Traits in an Elite Soft Red Winter Wheat Population

Although grain yield is the most important trait for growers, milling and baking industries demand high‐quality and scab‐free grains for various end products. To accelerate breeding of wheat (Triticum aestivum L.) cultivars with high grain quality, genetic dissection of quality traits is necessary. Genome‐wide association studies (GWAS) were conducted to identify genomic regions responsible for milling and baking quality traits in soft red winter wheat (SRWW). Seven quality traits were evaluated in two locations and 2 yr for 270 elite SRWW lines. These traits include flour yield, softness equivalent, flour protein, and four solvent (lactose, sodium carbonate, sucrose, and water) retention capacity measurements. In this study, 27,449 single nucleotide polymorphism (SNP) markers were developed by using both genotyping‐by‐sequencing and 90K SNP array technologies. A linear mixed model in GWAS, accounting for population structure and kinship, was fitted to identify 18 [−log(P) ≥ 4.0] genomic regions on 12 different chromosomes associated with the quality traits. Only one of these associations seems to be a previously identified quantitative trait locus, whereas others are novel associations. The most significant associations for quality traits were identified on chromosomes 1B, 2A, 2B, 4B, 5A, 7A, and 7D. Candidate gene searches, facilitated by the wheat genome assembly, led us to the identification of putative genes related to SRWW quality traits including fasciclin‐like arabinogalactan. The results of this study can be used in developing high‐quality SRWW varieties for the eastern region of the United States.

Bran characteristics influence the quality of whole‐wheat pancakes and baking powder biscuits

AbstractBackground and objectivesBran characteristics differ widely among wheat varieties and influence the quality of whole‐wheat products. The objective of this study was to identify bran characteristics that influence the quality of whole‐wheat pancakes and baking powder biscuits made from whole‐wheat meals (WWMs), which were blends of the brans of 17 soft red winter wheat varieties and two wheat flours.FindingsPancake diameters of 34 WWMs ranged from 106.6 to 116.0 mm. Biscuit height and shape factor (SF) of 34 WWMs ranged from 28.8 to 34.2 mm and 1.10–1.24, respectively. Bran protein content showed positive relationships with pancake diameter and biscuit height for both wheat flours blended with brans. Water‐retention capacity, free phenolics, and water‐extractable arabinoxylan contents of bran exhibited significant relationships with pancake diameter and biscuit SF in WWMs for only one wheat flour.ConclusionsWhole‐wheat meals containing brans of high protein content produced pancakes of comparable diameter to those made with wheat flour. WWMs containing bran of high protein and soluble dietary fiber (DF) contents, and low arabinoxylan and insoluble DF contents produced biscuits with intermediate‐to‐high height and low‐to‐intermediate SF.Significance and noveltyThe results identify bran characteristics desirable for making whole‐wheat pancakes and biscuits.

Fusarium and Alternaria mycotoxins present in Canadian wheat and durum harvest samples

The objectives of this work were to investigate the presence of a variety of mycotoxins in Canadian wheat and durum and to characterize the relationship between concentrations of the Fusarium-produced deoxynivalenol (DON) and the presence of visible Fusarium damage. There is a lack of reported mycotoxin surveillance data for Canadian wheat and durum; this work addresses this information gap. Wheat and durum harvest samples from the 2010, 2011 and 2013–2016 growing seasons were analysed for mycotoxins produced by a variety of fungal species, including Fusarium graminearum and Alternaria alternata. The Alternaria-produced tentoxin was observed the most frequently; it was present in 90% of the samples analysed at concentrations up to 0.063 mg kg−1. Fusarium-produced DON and enniatins B and B1 were present in over 70% of samples analysed. The plant transformation product DON-3-glucoside was quantified in up to 30% of samples. There was variability in the presence of the various mycotoxins amongst years. In particular, for DON, the variability reflected the level of visible Fusarium damage noted in grain samples. The geographic source of samples also influenced DON concentrations, which decreased from eastern to western growing regions on the Prairies. Concentrations of DON varied from 0.066 to 0.895 mg kg−1 in south central Manitoba and <0.03 to 0.053 mg kg−1 in central Alberta. DON concentrations were significantly correlated (P < 0.001) with visible Fusarium damage in Canada Western Red Spring wheat for all four years investigated. For Canada Eastern Soft Red Winter wheat and Canada Western Amber Durum, there were significant correlations (P < 0.001) in three of the four years investigated for each grain class. The years with no significant correlation between DON and Fusarium damage occurred when the presence of Fusarium species other than the DON-producing F. graminearum were predominant. This work provides a picture of the presence, and absence, of a number of mycotoxins in Canadian wheat and durum.

Characterization of an Ohio Isolate of Brome Mosaic Virus and Its Impact on the Development and Yield of Soft Red Winter Wheat.

Brome mosaic virus (BMV) is generally thought to be of little economic importance to crops; consequently, there is little information about its impact on wheat production under field conditions. After repeated detection of BMV in Ohio wheat fields at incidences up to 25%, the virus was isolated, sequenced, characterized, and tested for its impact on soft red winter wheat (SRWW). The Ohio isolate of brome mosaic virus (BMV-OH) was found to be >99% identical to a BMV-Fescue isolate (accession no. DQ530423-25) and capable of systemically infecting multiple monocot and dicot species, including cowpea and soybean, in experimental inoculations. BMV-OH was used in field experiments during the 2016 and 2017 growing seasons to quantify its effect on SRWW grain yield and development when inoculated at Feekes 1, 5, 8, and 10 in two to four cultivars. Cultivar and timing of inoculation had statistically significant (P < 0.05) main and interaction effects on grain yield, wheat growth, and multiple components of yield. Compared with noninoculated controls, BMV-OH reduced grain yield by up to 61% when inoculated at Feekes 1 and by as much as 25, 36, and 31% for inoculations at Feekes 5, 8, and 10, respectively. The magnitude of the yield reduction varied among cultivars and was associated with reductions in grain size and weight or plant population. These findings suggest that BMV could impact wheat productivity in Ohio and will serve as the basis for more large-scale investigations of the effects of this virus in commercial fields.

The structural evolution of water and gluten in refined and whole grain breads: A study of soft and hard wheat breads from postmixing to final product

AbstractBackground and objectivesRecent work investigating gluten secondary structure in dough systems has provided tantalizing insights as to how small perturbations in gluten structure may impact bread quality. Specifically, shifts in gluten structure from β‐turns to β‐sheets in doughs with bran may be partially responsible for quality defects in whole grain bread. This study aimed to further that knowledge by monitoring gluten secondary structure in soft and hard wheat refined and whole grain bread at different stages during processing. Commercial hard red spring (HW) and soft red winter wheat (SW) flours were used to make breads with whole grain doughs created by substituting bran for 15% of the refined flour. ATR‐FTIR spectra were collected from samples and analyzed for gluten secondary structural content.FindingsFreshly mixed doughs demonstrated the greatest β‐sheet content (53%–57%) compared to any other dough stage. Refined HW doughs demonstrated continual relaxation of β‐sheets to β‐turns through dough processing (−13% to panning), whereas relaxed SW doughs (−6% to 10%) partially reverted to sheets during punching and panning (1%–3%). The data also confirmed earlier findings that the presence of bran triggers the formation of additional β‐sheets (+4% to 5%) in both HW and SW doughs. Doughs with bran exhibited less structural relaxation (−3% to 6% β‐sheets) during processing. Interestingly, HW doughs exhibited only 1%–2% more β‐turns and only 1%–4% fewer β‐sheets than SW doughs. Analysis of the bread during baking revealed that SW generates a larger sheets:turns ratio compared to HW in refined bread, 21.3 versus 3.6, respectively, that grows to 129 versus 5.3 on addition of bran.ConclusionsGluten structural relaxation takes place during proofing in optimally hydrated doughs and largely follows water relaxation trends. The ratio of sheets:turns increases rapidly as water is lost during baking. The extent of this build‐up in the ratio is dependent on the wheat source for the flour (hard vs. soft wheat), presence/absence of bran, and the water loss (i.e., denaturation).Significance and noveltyThese results show that the ability of gluten to resist significant loss of bulk water during baking is related to better bread making performance. Additionally, the ability of gluten to resist substantial secondary structural alteration during baking, specifically formation of excessive β‐sheets, may be a key factor in high‐quality bread.

Registration of ‘Vision 50’ Wheat

Virginia Agricultural Experiment Station; Virginia Small Grains Board; Virginia Agricultural Council; Virginia Crop Improvement Association; Mennel Milling Company; Virginia Agricultural Experiment Station (Blacksburg); USDA National Institute of Food and Agriculture, US Department of Agriculture (Washington, DC)

Species, Seeding Rate, and Planting Method Influence Cover Crop Services Prior To Soybean

Core Ideas Drilling seed increased cover crop biomass but didn’t always improve establishment. With adequate moisture, planting method did not affect ground cover or winter weed biomass. Cereal rye produced more biomass than wheat and had less weed biomass. The lower seeding rate did not reduce cereal rye biomass. Higher seeding rate increased percent ground cover, but didn’t affect weed biomass. ABSTRACTSmall grain cover crops can be planted utilizing different methods. Due to their tillering capacity, seeding rates lower than current recommendations may offer adequate weed suppression and ground cover while they are growing. In 2 yr of field experiments, soft red winter wheat (Triticum aestivum L. ‘Pembroke’) and cereal winter rye (Secale cereale L. ‘Aroostook’) cover crops were planted following corn (Zea mays L.) by drilling or broadcasting 112 or 34 kg germinable seed ha−1 to examine how seeding rate and planting method influence plant establishment and density, biomass accumulation, winter weed suppression, and percent ground cover. Weather and soil conditions influenced cover crop biomass and ground cover produced by the two species planted at different rates using different methods, and thus subsequent weed suppression. When soil conditions were dry at and after planting, drilling seed led to higher plant density, cover crop biomass, percent ground cover, and lower weed biomass. In both years, cereal rye generally produced more biomass than wheat and contained less winter weed biomass. After a colder‐than‐average winter, percent ground cover with cereal rye was maintained at a higher level than with wheat. The higher seeding rate resulted in more ground cover, but did not affect winter weed biomass and did not consistently affect cover crop biomass. Generally, treatments that had more cover crop biomass also had higher percent ground cover and less winter weed biomass.

Genome-wide association studies for yield-related traits in soft red winter wheat grown in Virginia.

Grain yield is a trait of paramount importance in the breeding of all cereals. In wheat (Triticum aestivum L.), yield has steadily increased since the Green Revolution, though the current rate of increase is not forecasted to keep pace with demand due to growing world population and increasing affluence. While several genome-wide association studies (GWAS) on yield and related component traits have been performed in wheat, the previous lack of a reference genome has made comparisons between studies difficult. In this study, a GWAS for yield and yield-related traits was carried out on a population of 322 soft red winter wheat lines across a total of four rain-fed environments in the state of Virginia using single-nucleotide polymorphism (SNP) marker data generated by a genotyping-by-sequencing (GBS) protocol. Two separate mixed linear models were used to identify significant marker-trait associations (MTAs). The first was a single-locus model utilizing a leave-one-chromosome-out approach to estimating kinship. The second was a sub-setting kinship estimation multi-locus method (FarmCPU). The single-locus model identified nine significant MTAs for various yield-related traits, while the FarmCPU model identified 74 significant MTAs. The availability of the wheat reference genome allowed for the description of MTAs in terms of both genetic and physical positions, and enabled more extensive post-GWAS characterization of significant MTAs. The results indicate a number of promising candidate genes contributing to grain yield, including an ortholog of the rice aberrant panicle organization (APO1) protein and a gibberellin oxidase protein (GA2ox-A1) affecting the trait grains per square meter, an ortholog of the Arabidopsis thaliana mother of flowering time and terminal flowering 1 (MFT) gene affecting the trait seeds per square meter, and a B2 heat stress response protein affecting the trait seeds per head.

Soft Red and White Winter Wheat Response to Input‐Intensive Management

Core Ideas Prophylactic input applications failed to consistently increase wheat yield and net return without the presence of yield‐limiting factors. Traditional management significantly increased economic net return in three of four site‐years. Producers may wish to consider integrated pest management strategies for justification of input applications. Record grain yields and increased awareness of climate variability have more producers considering intensive (i.e., high‐input) wheat (Triticum aestivum L.) management. This study investigated soft winter wheat response to several agronomic inputs across intensive and traditional (i.e., low‐input) management systems. A four site‐year trial was established at Richville and Lansing, MI during 2015 and 2016 to evaluate the following inputs: increased rates of nitrogen (N) fertilizer, urease inhibitor (UI), nitrification inhibitor (NI), fungicide, plant growth regulator (PGR), and foliar micronutrients. Across four site‐years, intensive management did not increase yield compared to traditional management. In addition, traditional management increased average economic net return by $221 ha−1. At the reduced N rate, Richville 2016 yield decreased 0.94 Mg ha−1 within the intensive system suggesting greater N demand with intensive management. Due to significant stripe rust (Puccinia striiformis f. sp. tritici) occurrence, at 2016 Lansing, yield increased 0.75 Mg ha−1 when fungicide was added to the traditional system. Lansing 2017 yield decreased 0.52 Mg ha−1 when UI was removed from the intensive system, yet decreased 0.51 Mg ha−1 when UI was added to the traditional system. Heavy rainfall, lack of urea hydrolysis, and N rate likely contributed to the inconsistent UI response. The 2016 and 2017 growing seasons produced an overall absence of adverse environmental conditions which influenced negligible input responses. Although yield increases were observed, no single input increased net return. Results suggest intensive management benefits are unlikely at current wheat prices and without the presence of yield‐limiting factors.

Genetic mapping of a major gene for leaf rust resistance in soft red winter wheat cultivar AGS 2000

Leaf rust (LR), caused by Puccinia triticina (Pt), is a major disease of wheat worldwide. Genetic resistance is the most effective, economic, and environmentally safe method to reduce losses caused by LR. Seventy-nine LR resistance genes have been identified so far; however, only a few of them are still effective due to the constant evolution of new Pt races. The objectives of this study were to characterize the genetic basis of LR resistance in the soft red winter wheat (SRWW) cultivar AGS 2000 at seedling stage, and identify markers for marker-assisted selection (MAS). A mapping population of 175 recombinant inbred lines (RILs) was developed from a cross between the susceptible cultivar Pioneer® variety 26R61 (26R61) and AGS 2000. Two out of four Pt races (MBTNB, MFGKG, TCRKG, and MCTNB) showed segregating reactions for the parental lines and RIL population at the seedling stage. Whole genome QTL analysis detected a single common QTL for resistance to both Pt races (MFGKG and MBTNB) on chromosome 2BS. The gene was flanked by wPt-666389 and wPt-2600 markers and explained up to 75.3% of phenotypic variation for Pt race MBTNB, and is therefore a Mendelian factor. LR resistance genes, Lr13, Lr16, Lr23, Lr48, and Lr73, were all detected on 2BS; however, based on their physical and genetic positions, the gene was distinct and therefore temporarily designated as LrA2K. The closely linked marker Xwmc770 to LrA2K has been validated on a set of wheat cultivars and can be used in MAS for LR resistance.

Breeding for resilience to increasing temperatures: A field trial assessing genetic variation in soft red winter wheat.

Breeding for resilience to climate change is a daunting prospect. Crop and climate models tell us that global wheat yields are likely to decline as the climate warms, causing a significant risk to global food security. High temperatures are known to affect crop development yet breeding for tolerance to heat stress is difficult to achieve in field environments. We conducted an active warming study over two years to quantify the effects of heat stress on genetic variation of soft red winter (SRW) wheat (Triticum aestivum L.). Forty SRW cultivars and breeding lines were chosen based on marker genotypes at photoperiod sensitivity and reduced height loci. These genotypes were planted in a randomized complete block design replicated twice across two environments, ambient and artificially warmed. Average heading date occurred 5 days earlier in the warmed environment than in the ambient environment over both years (p ≤ 0.05). On average, grain yield was significantly reduced in the warmed environment by 211.41 kg/ha (p ≤ 0.05) or 4.84%, though we identified 13 genotypes with increased yield in response to warming in both years. Of these genotypes, eight had significantly increased N uptake while six showed significantly increased N utilization efficiency under warming. Under warming, genotypes with wild‐type alleles at the Rht‐D1 locus display significantly greater yields (p ≤ 0.01) and biomass (p ≤ 0.001) than genotypes with reduced height alleles. Of the 13 genotypes with higher (p ≤ 0.01) yields under warming, nine have the wild‐type allele at the Rht‐D1 locus in addition to being photoperiod insensitive. The next steps will be to validate these findings in other populations and to develop an efficient breeding/phenotyping scheme that will lead to more resilient cultivars.

Testing wheat for internal infesting insects with an electrically conductive roller mill

Although grain is always inspected for adult insects and insect damaged kernels upon shipping and receiving, immature insects living inside the kernels of grain cannot be readily detected. A laboratory roller mill was modified to measure and analyze the electrical conductance of wheat as it was crushed. The electrical conductance of normal wheat kernels is low and fairly constant. In contrast, the electrical conductance of infested wheat kernels produces a sudden change in the electrical signal. The peak height of the electrical spike depends on the size of the larvae and the resulting contact of the crushed larvae between the rolls. This instrument was designed to test wheat with moisture content of 13.5% or less. The laboratory mill can test a kilogram of wheat in less than 2 min. Hard red winter and soft red winter wheat samples were used in experiments. Known numbers of infested kernels were added to the wheat samples. The infested kernels contained larvae of rice weevils and lesser grain borers sorted into large, medium, and small size groups. The instrument detected ~8 of 10 infested kernels per 100 g of wheat with large-larvae (fourth instar or pupae). It detected ~7 of 10 infested kernels with medium-larvae (second or third instar) and ~5 of 10 infested kernels infested with the small-larvae (first or second instar). Under reasonable grain moisture and careful sample handling, there were no non-infested kernels classified as insect infested. The mill can lead to rapid and automated detection of infested wheat.

Registration of ‘Erisman’ Soft Red Winter Wheat

‘Erisman’ (Reg. No. CV‐1147, PI 687222) is an early‐maturing soft red winter wheat (Triticum aestivum L.) adapted to Illinois and surrounding states. It was developed by the University of Illinois Agricultural Experiment Station and released in 2017. Erisman was tested as IL10‐19516, with the pedigree ‘Bess’/IL00‐8530//IL00‐8530. Erisman has superior yield and test weight under both conventional and organic conditions. Over 36 trials, grain yield of Erisman averaged 5337 kg ha−1 compared with 4835 kg ha−1 for Bess and 4986 kg ha−1 for IL00‐8530. In organic trials, Erisman averaged 4371 kg ha−1 compared with 3762 kg ha−1 for ‘Kaskaskia’. Erisman averages 1.2 cm taller than Bess and is prone to lodging under high N in conventional farming systems, but not under organic farming systems. It is resistant to Fusarium head blight (FHB), stripe rust, Septoria tritici blotch, and Soil‐borne wheat mosaic virus (SBMV). Erisman was tested in multi‐location replicated yield trials, a five‐state cooperative nursey, a FHB disease nursery, a SBMV disease nursery, and on a certified organic farm. Erisman does not carry the Fhb1 resistance allele but does carry an allele on chromosome 5A associated with FHB resistance in ‘Ernie’. Erisman was chosen for release on the basis of its superior performance in both organic and conventional farming systems.

Photoperiod Response Gene Ppd‐D1 Affects Nitrogen Use Efficiency in Soft Red Winter Wheat

Optimal N application is critical to ensure profitable soft red winter wheat (Triticum aestivum L.) production and limit negative environmental effects. This study was conducted using 12 wheat lines grown in two Ohio and six Virginia environments to determine the effects of differentially split N rates on grain yield, yield components, and N‐related traits. Upon analysis of wheat lines in two contrasting photoperiod groups, it was discovered that wheat lines containing the photoperiod sensitivity allele (Ppd‐D1b) conferred a significant (P &lt; 0.05) yield advantage under N‐limited conditions in Ohio and across N treatments in half of the Virginia testing environments. This resulted from increased harvest index, grains per square meter, number of kernels per spike, and floret fertility in Ppd‐D1b lines relative to lines with the insensitive allele (Ppd‐D1a). However, wheat genotypes in the photoperiod‐insensitive allelic group had significantly higher (P &lt; 0.05) grain N concentration in all Virginia testing sites. A spring split N application of 33 kg N ha−1 at Zadoks growth stage (GS) 25 and 101 kg N ha−1 at Zadoks GS 30 produced the highest grain yields and grain N contents in five of the six Virginia environments. Nitrogen utilization efficiency was the primary contributor to variation in N use efficiency under higher N rates, whereas N uptake efficiency was the greatest contributor under low N rates. The contribution of N utilization and uptake efficiencies varied among wheat lines in the Ppd‐D1a group when 67 kg N ha−1 was applied at Zadoks GS 25 under the moderate and standard N rates.

Genome-Wide Association Studies to Identify Loci and Candidate Genes Controlling Kernel Weight and Length in a Historical United States Wheat Population.

Although kernel weight (KW) is a major component of grain yield, its contribution to yield genetic gain during breeding history has been minimal. This highlights an untapped potential for further increases in yield via improving KW. We investigated variation and genetics of KW and kernel length (KL) via genome-wide association studies (GWAS) using a historical and contemporary soft red winter wheat population representing 200 years of selection and breeding history in the United States. The observed changes of KW and KL over time did not show any conclusive trend. The population showed a structure, which was mainly explained by the time and location of germplasm development. Cluster sharing by germplasm from more than one breeding population was suggestive of episodes of germplasm exchange. Using 2 years of field-based phenotyping, we detected 26 quantitative trait loci (QTL) for KW and 27 QTL for KL with –log10(p) > 3.5. The search for candidate genes near the QTL on the wheat genome version IWGSCv1.0 has resulted in over 500 genes. The predicted functions of several of these genes are related to kernel development, photosynthesis, sucrose and starch synthesis, and assimilate remobilization and transport. We also evaluated the effect of allelic polymorphism of genes previously reported for KW and KL by using Kompetitive Allele Specific PCR (KASP) markers. Only TaGW2 showed significant association with KW. Two genes, i.e., TaSus2-2B and TaGS-D1 showed significant association with KL. Further physiological studies are needed to decipher the involvement of these genes in KW and KL development.