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Herbicide‐resistant wheat cultivars are an effective tool in controlling weeds. The CoAxium wheat (Triticum aestivum L.) cultivar conferring tolerance to quizalofop‐p‐ethyl herbicide was developed along with a bioassay to quantify traited seeds in a sample. The objectives of this study were to (1) compare a current seed soaking (SS) method with substrate imbibition (SI) method in detecting AXigen trait in two genotypes, CO14A050 (homozygous resistant‐A/D genomes) and CO14A136 (homozygous resistant‐B/D genomes), and (2) develop criteria to distinguish between trait and nontrait seedlings based on chemical injury using standard germination, linear length, and dry matter content tests. Quizalofop doses 0.0, 3.0, 4.0, and 5.0 μM were used in both methods. A soft white winter wheat, Bobtail, was used as a susceptible control. Using SS, 96% of Bobtail seedlings were classified as nontrait at 3.0 μM and 100% at 4.0 and 5.0 μM; however, using SI, only 1.0%–6.0% showed chemical injury and were classified as nontrait. The SI did not differentiate between trait and nontrait seedlings at any dose. At 5 μM, CO14A136 showed significant chemical injury (26%) compared to CO14A050 (1%). A greenhouse dose–response study confirmed that CO14A136 conferred lower tolerance to quizalofop than CO14A050. The SS method at 5 μM was suitable for identifying trait and nontrait seeds. It is recommended that both root and shoot structure should be considered in evaluating trait and nontrait seedlings, not only roots like the current protocol. Core Ideas: Seed soaking bioassay at 5.0 μM dose identified quizalofop tolerant wheat seeds effectively.Substrate imbibition method at 5–20 μM was not reliable to detect quizalofop‐tolerant seeds.Both root and shoot structures should be considered in evaluating trait and nontrait seedlings. [ABSTRACT FROM AUTHOR]

Genetic improvement of crop plants is dependent on the availability of genetic variation, which can be present naturally or can be created using mutations. Ethyl methanesulfonate (EMS) mutagenesis provides an attractive tool to create variant alleles of genes of interest in any plant. In the present paper, we report development of an EMS‐mutagenized population in a hard red winter wheat (Triticum aestivum L.) variety Jagger. Jagger has been a leading variety across the United States and has been grown internationally as well, for over two decades now. It possesses many useful traits related to disease resistance, cold tolerance, and milling and baking qualities. Because it is a landmark variety, the genome of Jagger is being sequenced by an international collaborative team, which will speed up gene mapping and cloning efforts in it. The Jagger Targeting Induced Local Lesions In Genome (TILLING) resource developed in this work will be useful for functional validation of these genes. The mutagenized population was developed using EMS and was characterized phenotypically and genotypically. Gene‐wise mutation screening was performed for three genes located on different chromosomes across all the three genomes. The population has an overall mutation frequency of 1/40.7 kb, and we were able to find multiple knockout, missense, and missplicing mutations for each targeted gene. The population will be useful as a forward and reverse genetic screen for a number of valuable traits. [ABSTRACT FROM AUTHOR]

The principal goals of a plant breeding program are to provide breeders with cultivar information for selection purposes and to provide farmers with high‐yielding and stable cultivars. For that reason, multi‐environment trials need to be done to predict future cultivar yield, and a robust statistical procedure is needed to provide reliable information on the tested cultivars. In Sweden, the statistical procedure follows the tradition of modeling cultivar effects as fixed. Moreover, the analysis is performed separately by zone and level of fungicide treatment, and so the factorial information regarding cultivar × zone × fungicide combinations is not explored. Thus, the question arose whether the statistical method could be improved to increase accuracy in zone‐based cultivar prediction, since the cultivar recommendation is zone based. In this paper, the performance of empirical best linear unbiased estimation (E‐BLUE) and empirical best linear unbiased prediction (E‐BLUP) are compared using cross‐validation for winter wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.), in single‐year and multiyear series of trials. Data were obtained from three agricultural zones of Sweden. Several linear mixed models were compared, and model performance was evaluated using the mean squared error of prediction criterion. The E‐BLUP method outperformed the E‐BLUE method in both crops and series. The prediction accuracy for zone‐based yield was improved by using E‐BLUP because the random‐effects assumption for cultivar × zone interaction allows information to be borrowed across zones. We conclude that E‐BLUP should replace the currently used E‐BLUE approach to predict zone‐based cultivar yield. [ABSTRACT FROM AUTHOR]

For sustainable productivity, a winter wheat (Triticum aestivum L.)–summer crop (corn [Zea mays L.] or grain sorghum [Sorghum bicolor L.])–fallow (W‐SC‐F) cropping system could benefit from optimal wheat stubble cutting height management, but only limited information is available. The objective of this study was to evaluate the effect of wheat stubble height on subsequent corn and grain sorghum yields, available soil water, crop water use, and precipitation storage efficiency in a W‐C‐F and W‐S‐F cropping system. This study was conducted from 2006 through 2020 at the Kansas State University Southwest Research‐Extension Center near Tribune, KS. The experimental design was a randomized complete block with three wheat stubble heights (high, low, and strip). Average across all years, there was a 9%–10% corn yield and 7%–11% corn biomass advantage from high and stripper harvested wheat stubble compared with low cut stubble, and a 5% sorghum yield advantage from high cut stubble compared with low cut stubble. Kernel weight of corn was the only yield component that significantly differed among stubble height treatments. Water productivity of corn in the high and stripper harvested stubble treatments (15.3 kg ha−1 mm−1) was significantly greater compared with the low cut stubble (14 kg ha−1 mm−1). Water productivity of sorghum in the high cut stubble treatment (18.9 kg ha−1 mm−1) was also significantly greater compared with low cut stubble (17.7 kg ha−1 mm−1). Total available soil water at planting (ASWP) and available soil water at harvest (ASWH) of corn were both greater for high cut stubble compared with stripper harvested stubble but total ASWP and ASWH of grain sorghum were not significantly different among stubble height treatments. We concluded that low cut wheat stubble decreased subsequent corn and grain sorghum yields in a W‐C/S‐F cropping system. Core ideas: There was a 9%–10% corn yield and 7%–11% biomass advantage from high and stripper harvested compared with low cut wheat stubble.There was a 5% sorghum yield increase from high cut stubble compared with low cut wheat stubble.Kernel weight of corn was the only yield component that significantly differed in response to wheat stubble height.Water productivity of corn and sorghum in the high and stripper harvested was significantly greater compared with low cut wheat stubble. [ABSTRACT FROM AUTHOR]

The development and improvement of crop cultivars are necessary to meet the demands of the growing global population. The ability to decrease the generation time is imperative for breeders to achieve higher rates of genetic gain annually. Understanding the way in which photoperiod affects the maturation rate of these crops, including winter wheat (Triticum aestivum L.), is required for decreasing generation time in breeding programs. The effects of prolonged photoperiod and light intensity on winter wheat generation time were studied to determine if photoperiod may contribute to a shortened cycle time. Three winter wheat cultivars (Branson, CFBA1401, and Norstar) and one spring wheat cultivar (AC Carberry) were exposed to four treatments based on the daily light integral (DLI): high light (HL) or low light and photoperiod as follows: 22 h of light and 2 h of dark (22:2) or 16 h of light and 8 h of dark (16:8). Generation time, as measured by days to maturity in the HL22:2 treatment, resulted in a decrease of 8 days or 7% of the total generation time, compared to the control, HL16:8 treatment. Photoperiod itself had a minimal effect on generation time when both DLI and temperature were controlled. An improved understanding of the effects of photoperiod, thermal time, and DLI and their interactions is required prior to implementation in a winter cereal breeding program. Core Ideas: Accelerating plant growth using a post‐vernalization method has shown differences between spring and winter wheat.Photoperiod has a minor effect on decreasing days to anthesis when temperature is controlled.Results provide evidence for controlling all contributing factors to increase growth rate. [ABSTRACT FROM AUTHOR]

Vegetative filter strip characteristics such as perenniality drive hydrology and subsequent ecosystem services. However, the extent and the potential for forage–biomass crops to improve water quality, provide fodder, and optimize nutrient cycling in multifunctional systems is unknown. We evaluated (a) how species, perenniality, and plant community composition are linked to water quality; and (b) the multiuse forage–biomass potential of filter strips. Whole plots were species [eastern gamagrass (Tripsacum dactyloides), Kernza [or intermediate wheatgrass (Thinopyrum intermedium)], silphium (Silphium integrifolium), switchgrass (Panicum virgatum), and winter wheat (Triticum aestivum)], with split‐plots receiving 0 or 5.6 Mg ha−1 broiler litter. Rainfall simulations were conducted at 5 cm h−1 (until 30 min of continuous runoff) in summer and fall of 2019 and 2021 with dual forage and biomass harvests occurring 2019–2021. Kernza and silphium had the lowest biomass regrowth after forage harvests relative to native grasses, suggesting they would not be ideal multifunctional forage–bioenergy crops. Among all soil–plant–water variables, canonical correlations indicate poultry litter (.97), and soil phosphorus saturation (.77) were the most influential variables for water quality. Water quality score, FWQ, which is inversely related to runoff water quality, was lowest for switchgrass (0.03) and greatest (P ≥.05) for eastern gamagrass and wheat (1.77 and 3.33, respectively), but not different from Kernza (0.98) and silphium (0.31). Therefore, switchgrass resulted in the best water quality scores and highest forage–biomass yields, with Kernza and silphium also showing promise for reducing sediment and nutrient loads following poultry litter applications in multifunctional filter strip systems. Core Ideas: Filter strip characteristics drive surface hydrology and subsequent ecosystem services. Greatest multiuse (forage–biomass filter strip) yields occurred for switchgrass. Poultry litter applications and soil P saturation were most correlated with water quality. Perennial crops (excluding eastern gamagrass) improved water quality. Switchgrass had the highest water quality and biomass yields, indicating greatest multiuse filter strip potential. [ABSTRACT FROM AUTHOR]

Conventional selected‐bulk breeding is a low cost means of advancing populations but requires years of selection in the field to generate fixed lines. Doubled haploid (DH) methods produce fixed lines quickly but without selection and at high cost. The 'Minibulk' system was developed to combine the speed of DHs with the population size and crossover opportunities of selected‐bulk breeding. Breeding populations of winter wheat (Triticum aestivum L.) were vernalized and advanced at high density in the greenhouse from the F2 to the F4 generation. F4 populations underwent visual selection in the field, and derived lines were genotyped for variants at photoperiod and vernalization alleles and across the genome using genotyping‐by‐sequencing. The number of crossover events and parental genome contributions were determined for recombinant inbred lines (RILs) within populations and among RILs across populations. During vernalization, seeds in all populations germinated and underwent vegetative growth, forming a dense seed mat that was transplanted directly into greenhouse pots. A 22‐h photoperiod accelerated development, and many populations reached physiological maturity as soon as five weeks after transplanting. Increasing the number of seeds planted from 300 in the F2 to 500 in the F3 increased the number of fertile spikes produced, thereby maintaining a larger population size. The number of crossovers detected differed significantly between populations and chromosomes, while the number of crossovers detected in each population was related to marker density. Adoption of the minibulk system by winter cereal breeding programs can lead to significant cost savings and acceleration of the breeding cycle. Core Ideas: The minibulk system integrates rapid generation advancement with high‐density planting.Lines derived using the minbulk system can follow the same timeline as doubled haploids.Minibulks combine the recombination events and population size of selected‐bulk breeding. [ABSTRACT FROM AUTHOR]

The impact of drought on wheat (Triticum aestivum L.) production is shown, using an example data set of almost 60 yr from six climate‐specific regions in Poland. Drought was measured using the standardized precipitation index (SPI) and the hydro‐thermal coefficient of Selyaninov (HTC). Yield trends were estimated by Bayesian linear regression over two periods, 1961–1991 and 1992–2019, identified by a changepoint detection method. Bayesian inference is used as it allows the estimation of a credible interval of regression coefficients instead of point estimates and asymptotic confidence intervals, thus comparisons between regression coefficients are more meaningful. We detected an increase in yield in both time periods and in all regions. The average winter wheat yield increased by 97% in the first period and by 35% in the second (19.8–39.1 dt ha−1 and 32.9–44.5 dt ha−1, respectively). Spring wheat yield increased by 96% in the first period and by 42% in the second (16.8–37.9 and 22.9–32.5 dt ha−1, respectively). Yield losses in drought years were estimated using the paired t test to compare mean difference between real yields and yields estimated from regression lines for nondrought years. The highest yield losses due to drought were in regions I (–19.3% spring wheats, –6.3% winter ones) and III (–16.1% spring and –8.3% winter wheats) over the 1992–2019 period. Core Ideas: Wheat production is limited due to spring droughts.Yield loss in spring wheat cultivars is more pronounced compared to that in winter ones.Yield‐based selection generally results in improvement of wheat drought tolerance. [ABSTRACT FROM AUTHOR]

Freezing tolerance is likely to be an important adaptation for both natural populations and crop cultivars like winter wheat (Triticum aestivum L.). In the United States, winter wheat represents 80% of the total wheat production. Understanding the genetic basis of freezing tolerance in wheat furthers our knowledge of abiotic stress tolerance in plants and may inform breeding programs aimed at adjusting the level of freezing tolerance for a given region. We examined freezing tolerance in a 267‐line panel of elite soft red winter wheat that has previously been used for genome‐wide association study (GWAS) on agronomically important traits. We were specifically interested in determining the extent of genetic variation for freezing tolerance within the panel, what the genetic basis of that variation is, and if there are correlations between freezing tolerance and other agronomically important traits. We found significant variation in freezing tolerance among the lines, measured as survival through three total days at −8 °C. We performed a GWAS on freezing tolerance and identified 13 candidate loci, with nearby candidate genes involved in different functions potentially associated with freezing tolerance. In addition, we found significant correlations between freezing tolerance and seven previously published yield related traits. In summary, we found considerable variation in freezing tolerance in this panel that is associated with yield related traits. Thus, these lines may be useful for breeding programs seeking to optimize freezing tolerance for present and future climatic conditions. Core Ideas: Substantial genetic variation for freezing tolerance was found within a winter wheat panel.This variation has a polygenic basis, and 13 candidate loci were identified.There is a modest positive correlation between freezing tolerance and published yield estimates.Genetic variation in freezing tolerance may be useful for eastern US breeding programs. [ABSTRACT FROM AUTHOR]

Genomic selection (GS) can improve genetic gain of complex traits in plant breeding. Phenotyping agronomic traits of winter wheat (Triticum aestivum L.) for dual‐purpose use is expensive and time‐consuming. In this study, we compared the prediction accuracies of four GS models (RR‐BLUP, GBLUP, GAUSS, and BL) for forage yield (FY), plant height (PH) and heading date (HD) of the hard winter wheat diversity panel (n = 298) using random and stratified sampling methods. In addition, we determined the appropriate training population (TP) size and marker density for GS of the traits. Moderate to high prediction accuracies ranging from 0.66 to 0.69 for FY, 0.46 to 0.49 for PH, and 0.71 to 0.74 for HD were observed for the GS models. However, the sampling method had little or no impact on prediction accuracy. The RR‐BLUP, GBLUP, and GAUSS models produced slightly greater prediction accuracies than BL for all traits studied. Prediction accuracies increased with increasing TP size and marker density in all the GS models tested. However, increase of prediction accuracy started to plateau at nTP = 180 lines and 1,000; 1,500; or 3,000 SNPs suggesting that the minimum TP size and marker density were about 180 lines and 1,000 or more SNPs, depending on the model and trait. The impact of TP size on prediction accuracy was greater for RR‐BLUP, GAUSS, and GBLUP than for BL model. This study suggests that RR‐BLUP, GBLUP, and GAUSS are viable models for selecting the forage agronomic traits during dual‐purpose wheat breeding. [ABSTRACT FROM AUTHOR]

Freeze tolerance is greatest in winter wheat (Triticum aestivum L.) during winter dormancy and decreases as the plant develops in the spring. Above‐average temperatures during the winter and spring have resulted in wheat resuming growth earlier in the season, exposing a less freeze‐tolerant plant to an increased risk of spring freeze events. The objective of this study was to determine the effect of temperature on seed yield components and biomass of field‐acclimated winter wheat at Feekes 6, 8, and 10.5.1 growth stages. Five soft red winter wheat cultivars were transplanted from the field into pots at each Feekes growth stage identified above. Plants were placed into freeze chambers with temperature treatments ranging from −16 to 4°C. Plants were exposed to the treatment temperature for 15 min and placed in a cooler maintained at 4°C. After 20 h, plants were moved to an open‐air greenhouse and grown to maturity. At maturity, yield component and biomass data were recorded. Temperature treatments of −10, −7, and −3°C reduced seed weight at Feekes 6, 8, and 10.5.1 growth stages, respectively, compared with plants held at 4°C. Plant biomass was reduced at Feekes 6 and 8 growth stages at −10 and −4°C, respectively. These guidelines will help producers better estimate the potential value of a freeze‐damaged wheat crop. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Late summer planting of winter wheat (Triticum aestivum L.) into tilled fallow is necessary for production of maximum yield in many areas of the low precipitation (<30 cm, annual) zone of the inland Pacific Northwest region of the United States. Farmers plant deep to reach moisture adequate for germination and emergence. The coleoptile of deep‐planted wheat remains underground. The first leaf protrudes through the tip of the coleoptile and usually emerges about 10 to 12 d after planting. Emergence may be jeopardized by below‐surface buckling of the first leaf. Buckling of the first leaf occurs when its exerted force cannot overcome the density or strength of overlying soil. Small, single‐point load cells were used to measure force exerted by the first leaf of one semidwarf cultivar ('Norwest 553') and two standard‐height cultivars ('Farnum' and 'Finley') as they emerged from a deep planting depth (100 mm) in a small containerized volume of soil. The average maximum before‐buckling emergence force (BBEF) of Norwest 553 and Finley was 12.2 and 11.6 g, respectively. The corresponding value for Farnum (10.9 g) was statistically similar to the BBEF of Finley and less than that of Norwest 553. The measured difference between Farnum and Norwest 553 may be a consequence of variation in coleoptile diameter. Maximum diameter measurements of 1.6 to 1.7 mm were made near the base and in the middle of the Norwest 553 coleoptile. New knowledge generated from this research can be used to make decisions about the focus of future investigations that deal with poorly understood mechanisms responsible for emergence of wheat from deep planting depths. [ABSTRACT FROM AUTHOR]