Winter Growth Habit Research Articles

Recessive Winter Growth Habit Allele on 5B Chromosome, vrn-B1, Improves Earliness and Grain Yield of Bread Wheat

Recessive Winter Growth Habit Allele on 5B Chromosome, vrn-B1, Improves Earliness and Grain Yield of Bread Wheat

Evaluation of the Allelic Variations in Vernalisation (VRN1) and Photoperiod (PPD1) Genes and Genetic Diversity in a Spanish Spelt Wheat Collection.

Allelic variation within genes controlling the vernalisation requirement (VRN1) and photoperiod response (PPD1) determines the adaptation of wheat to different environmental growing conditions as well as influences other traits related to grain yield. This study aimed to screen a Spanish spelt wheat collection using gene-specific molecular markers for VRN-A1, VRN-B1, VRN-D1, and PPD-D1 loci and to phenotype for heading date (HD) in both field and greenhouse experiments under a long photoperiod and without vernalisation. Fifty-five spelt genotypes (91.7%) exhibited a spring growth habit, and all of them carried at least one dominant VRN1 allele, whereas five (8.3%) genotypes had a winter growth habit, and they carried the triple recessive allele combination. The Vrn-D1s was the most frequent allele in the studied set of spelt accessions, and it was found in combination with both the dominant Vrn-A1b and/or Vrn-B1a alleles in 88.3% of the spelt accessions tested. All spelt accessions carried the photoperiod-sensitive Ppd-D1b allele, which may explain the late heading of spelt germplasm compared to the commercial spring bread wheat Setenil used as a control. The least significant difference test showed significant differences between allelic combinations, the earliest accessions being those carrying two or three dominant alleles, followed by the one-gene combinations. In addition, the genetic diversity was evaluated through capillary electrophoresis using 15 wheat simple sequence repeat (SSR) markers. Most markers had high levels of polymorphism, producing 95 different alleles which ranged between 53 and 279 bp in size. Based on the polymorphic information content values obtained (from 0.51 to 0.97), 12 out of the 15 SSRs were catalogued as informative markers (values > 0.5). According to the dendrogram generated, the spelt accessions clustered as a separate group from the commercial bread wheat Setenil. Knowledge of VRN1 and PPD1 alleles, heading time, and genetic variability using SSR markers is valuable for spelt wheat breeding programs.

Antioxidant Activity and Essential Amino acid Content of Bread Wheat (Triticum aestivum L.) Varieties

In recent years, consumption of healthy and nutritious products has come to the forefront with the increased consumers’ awareness because of sensitivity to human health. Bread wheat provides the important proportion of protein, fiber, mineral, and antioxidant compounds that detected wheat and wheat-based products in daily consumption. The study aimed to provide new insights and results on the antioxidant properties and essential amino acid profile of 45 bread wheat varieties collected from different ecological regions of Turkey. Antioxidant activity was measured using DPPH radical and total phenolic content was determined by using the Folin-Ciocalteu method used gallic acid as standard. Essential amino acid content was evaluated by oxidation and hydrolysis procedure by HPLC analysis. As a result of the study, significant differences and correlations were found between the varieties and all evaluated parameters. Total phenolic content and antioxidant activity values respectively ranged between 102.4 and 211.8 μg GAE/g (gallic acid equivalent/g), 11.8 and 26.3% inhibition in whole wheat flour. Amino acid amount and profile were significantly affected by variety and the most limiting amino acid lysine showed a wide range (0.39-1.47 g/100 g flour) and the concentration of leucine and phenylalanine were found to be higher in wheat compared to the other essential amino acids. Correlation analysis between protein and essential amino acids demonstrated a positive correlation with high values. Clustering analysis highlighted an important genetic diversity, suggesting that winter growth habit varieties have valuable nourishment properties with high protein and amino acid composition. These data suggest that health and nourishment properties influenced differently by genotype potential of wheat grain.

Inheritance of growth habit in einkorn wheat

Aim. Find out the inheritance patterns of the trait “winterness / springness” in hybrids between representatives of einkorn wheat species. Methods. Crossings were carried out using the “single cross” method. The nature of inheritance of the growth habit was determined using hybridological analysis. Results. It has been shown that in the hybrids of wild wheat forms T. boeoticum and T. urartu with cultivated T monococcum and T. sinskajae, the winter growth habit of wild forms dominates over the spring one of cultivated forms. Differences in “winterness / springness” phenotype between parental forms in crosses of T.monococcum var. macedonicum with T.urartu var. spontaneorubrum and T.boeoticum var. bicolor; T.sinskajae var. sinskajae with T.urartu var. spontaneorubrum and T.boeoticum var. thaoudar; T.boeoticum var. thaoudar with T.monococcum var. monococcum, T.sinskajae var. sinskajae and T.monococcum var. macedonicum; T.boeoticum var. kurbagalensense with T.sinskajae var. sinskajae and T.monococcum var. monococcum are controlled by a single gene. The difference between the two wild forms in crossing T.boeoticum var. thaoudar × T.boeoticum var. kurbagalensense is controlled by two genes. In the crosses T.boeoticum var. thaoudar with T.monococcum var. monococcum, T.sinskajae var. sinskajae and T.monococcum var. macedonicum; T.boeoticum var. kurbagalensense × T.sinskajae var. sinskajae, the parental forms also differ digenously. Conclusions. Winterness of einkorn wheat wild forms dominates over the springness of cultivated forms. The difference in the growth habit between the studied einkorn forms is due to differences in 1 – 2 pairs of genes.

Phenotyping winter wheat for early ground cover

The relationship between the early ground cover and the grain yield in winter wheat is not yet fully understood. In a winter wheat breeding programme, selection for early ground cover is traditionally made using visual scoring. Although visual scoring is preferred as a phenotypic screening tool by wheat breeders, its output may not be reliable, as it requires experience. A smartphone camera-based digital image technique can be recommended as a feasible, reliable, repeatable, affordable, and fast selection tool for early ground cover in wheat as an alternative to visual scoring. For this purpose, two wheat trials were conducted in the 2017–2018 and 2019–2020 seasons. In both seasons, 215 wheat genotypes in total, together with three checks from spring wheat, were tested under rain-fed conditions in the spring wheat zone in Turkey. All the tested wheat genotypes were grouped into spring, facultative, and winter growth habit using visual scoring. Simultaneously, photos were taken from each plot with a smartphone camera, and the early ground cover (%) was estimated using the smartphone camera-based digital image technique. The relationships between grain yield, visual scoring, and early ground cover could so be estimated. In both seasons, significant negative correlation between grain yield and visual scoring (r = −0.679** and r = −0.704**, respectively) and significant positive correlation between the grain yield and the early ground cover (r = 0.745** and r = 0.747**, respectively) were observed. The correlation between visual scoring and early ground cover were negative (r = −0.862** and r = −0.926**, respectively). The broad sense heritability estimates in both seasons were 0.51 and 0.85, respectively, for early ground cover, 0.91 and 0.94 for visual scoring, and 0.86 and 0.69 for grain yield. In this study, we revealed that testing winter wheat genotypes in the spring wheat zone rather than in the winter wheat zone could be a more effective way to unveil the positive relationship between the early ground cover and the grain yield. We have shown that the smartphone-based digital image technique is a useful selection tool for early ground cover in winter wheat.

Temporal Expression Analysis of Barley Disproportionating Enzyme 1 (DPE1) during Grain Development and Malting

Disproportionating enzyme (D-enzyme) is a 4-α-glucanotransferase (EC 2.4.1.25) that disproportionates α-glucans and maltooligosaccharides and preferentially disproportionates maltotriose into maltopentaose and glucose. Maltotriose is a maltooligosaccharide that accumulates in barley malt and wort without being digested further by starch degrading enzymes. Furthermore, not all brewer’s yeast strains can ferment maltotriose. This research was undertaken to determine if D-enzyme is expressed in developing and/or malting barley grains and thus providing evidence of an inherent enzymatic mechanism capable of disproportionating maltotriose into maltopentaose that can be further degraded into fermentable sugars by amylolytic enzymes such as β-amylase. A partial genomic sequence of barley disproportionating enzyme 1 (DPE1) was obtained that was comprised of 16 exons and 15 introns totaling 4680 bp. The 5’ region of the DPE1 gene was recalcitrant to Sanger sequencing owing to its localization in a highly repetitive region of the barley genome. The DPE1 gene is expressed during grain development and the protein stored in the mature grain. Additionally, the DPE1 gene is de novo expressed during malting in both a 2- and 6-row malting cultivar with significant variation observed amongst 13 elite malting cultivars representing spring and winter growth habits. During grain development, DPE1 mRNA levels peak at 17 days after anthesis, which coincides with a large increase in proteins that react to anti-DPE1 polyclonal antibodies. These proteins appear as a doublet on immunoblots during initial stages of malting and as a singlet as malting progresses indicating proteolytic processing (e.g., transit peptide removal) or differential isoform/splice variant expression.

Association of the Recessive Allele vrn-D1 With Winter Frost Tolerance in Bread Wheat.

Winter frost has been considered the primary limiting factor in wheat production. Shimai 12 is an elite wheat cultivar grown in central and southern Hebei province of China, but sensitive to winter frost. In this study, the winter frost tolerant cultivar Lunxuan 103 was bred by introducing the recessive allele vrn-D1 from winter wheat Shijiazhuang 8 (frost tolerance) into Shimai 12 using marker-assisted selection (MAS). Different from Shimai 12, Lunxuan 103 exhibited a winter growth habit with strong winter frost tolerance. In the Shimai 12 × Shijiazhuang 8 population, the winter progenies (vrn-D1vrn-D1) had significantly lower winter-killed seedling/tiller rates than spring progenies (Vrn-D1aVrn-D1a), and the consistent result was observed in an association population. Winter frost damage caused a significant decrease in grain yield and spike number/m2 in Shimai 12, but not in Lunxuan 103 and Shijiazhuang 8. The time-course expression analysis showed that the transcript accumulation levels of the cold-responsive genes were higher in Lunxuan 103 and Shijiazhuang 8 than in Shimai 12. Lunxuan 103 possessed the same alleles as its parents in the loci for plant height, vernalization, and photoperiod, except for the vernalization gene Vrn-D1. An analysis of genomic composition showed that the two parents contributed similar proportions of genetic compositions to Lunxuan 103. This study provides an example of the improvement of winter frost tolerance by introducing the recessive vernalization gene in bread wheat.

Registration of ‘SB255’ winter barley

Abstract‘SB255’ (Reg. no. CV‐373, PI 693987) is a six‐rowed hulled barley (Hordeum vulgare L.) cultivar with winter growth habit. The cultivar was released by the Virginia Agricultural Experiment Station in May 2019. SB255 is widely adapted, high yielding, high grain volume weight, and medium tall. It has good winterhardiness and good straw strength. The spikes of SB255 are strap and slightly waxy with no overlapping lateral kernels and with long awns. Prior to being named, SB255 was tested under the experimental designation VA11B‐141 (LA). It was derived from the cross Spont03‐44/VA01B‐44 and developed using a modified‐bulk breeding method. It was evaluated from 2013 to 2019 in the Virginia Official Variety Trials at five to six locations. SB255's average grain yield (5,214 kg ha–1) was similar to the check cultivars ‘Secretariat’ and ‘Thoroughbred’ but significantly (P ≤ .05) higher than ‘Atlantic’, ‘Price’, ‘Callao’, ‘Nomini’, and ‘Wysor’. Average grain volume weight of SB255 (60.8 kg hL–1) was similar to Secretariat and Price but exceeded (P ≤ 0.05) those of Thoroughbred, Atlantic, Callao, Nomini, and Wysor. Head emergence of SB255 was similar to Thoroughbred and 2–5 d later than winter feed barley cultivars Secretariat, Atlantic, Price, Callao, and Nomini. SB255 was developed primarily as a feed barley cultivar. It provides barley producers and end users in the eastern United States with a high‐grain‐yielding cultivar having good to moderate resistance to all diseases prevalent in the eastern United States, including Fusarium head blight (FHB), and also lower deoxynivalenol (DON) accumulation in the grain.

Genetic diversity in historical and modern wheat varieties of the U.S. Pacific Northwest

AbstractLoss of crop genetic diversity due to modern plant breeding is an enduring global concern. The U.S. Pacific Northwest (PNW) is an important wheat (Triticum aestivum L.)‐producing region. We examined population structure and changes in genomic‐level and agroecosystem‐level genetic diversity of PNW wheat over the past 120 yr. Wheat varieties were slightly structured by spring and winter growth habit, but not by geographic origin or period of variety release. At the genomic level, we did not find long‐term shifts in gene diversity in either spring or winter wheat, but fluctuations were significant within market classes and within the most widely grown spring and winter varieties. Diversity in hard red spring (HRS) wheat peaked in 1970–1999 and since dropped below the level of varieties before 1930. Hard red winter (HRW) in 2000–2019 is more diverse than before 1930, whereas soft white spring (SWS) and soft white winter (SWW) are at the same level of diversity in 2000–2019 as they were before 1930. The most widely grown spring varieties had the lowest diversity in 1930–1969, whereas the most widely grown winter varieties had the lowest diversity in 2000–2019. At the agroecosystem level, Simpson's index of diversity (1 − D) has been on a rising trend since the 1990s as the dominance of acreages by a few varieties has become less common. Cultivation of multiple market classes and periodic incorporation of new germplasm by breeding programs have been able to maintain the quantitative level of genetic diversity in PNW wheat over time.

Application of image-based phenotyping tools to identify QTL for in-field winter survival of winter wheat (Triticum aestivum L.).

Genome-wide association on winter survival was conducted using data from image-based phenotyping method. Nine QTL were observed and three of them with candidate gene identified. Winter survival is an essential trait of winter wheat (Triticum aestivum L.) grown in regions with high risk of winterkill. We characterized a diversity panel of 450 Canadian wheat varieties that included mostly winter-growth habit wheats to identify key genetic factors that contribute to higher winter survival under field conditions. To more accurately quantify winter survival differences among varieties, image-based phenotyping methods, captured by unmanned aerial vehicle (UAV) and on ground level, were used to estimate the winter survival of each varieties. Winter survival index was developed to correct for emergence when evaluating winter survival. Winter survival measurement estimated by visual estimation, UAV imagery and ground imagery showed strong correlation with each other and had comparable broad-sense heritability. Genome-wide association studies resulted in the identification of seven quantitative trait loci (QTL) for winter survival including Vrn-A1. By using the recently released annotated sequence of the wheat genome and the available RNA-Seq data, two putative candidate genes underlying the QTL for winter survival were identified.However, our study showed that certain QTL was unique to specific winter survival measurement. Collectively, our study demonstrated the feasibility of using UAV-based imagery for the identification of loci associated with winter survival in wheat. The complexity of in-field condition make our result a valuable complement to indoor frost-tolerance studies in the identification of genetic factors not directly linked to freezing tolerance.

Genome-Wide Association Analysis of Grain Yield-Associated Traits in a Pan-European Barley Cultivar Collection.

A collection of 379 Hordeum vulgare cultivars, comprising all combinations of spring and winter growth habits with two and six row ear type, was screened by genome wide association analysis to discover alleles controlling traits related to grain yield. Genotypes were obtained at 6,810 segregating gene-based single nucleotide polymorphism (SNP) loci and corresponding field trial data were obtained for eight traits related to grain yield at four European sites in three countries over two growth years. The combined data were analyzed and statistically significant associations between the traits and regions of the barley genomes were obtained. Combining this information with the high resolution gene map for barley allowed the identification of candidate genes underlying all scored traits and superposition of this information with the known genomics of grain trait genes in rice resulted in the assignation of 13 putative barley genes controlling grain traits in European cultivated barley. Several of these genes are associated with grain traits in both winter and spring barley.

Characterization of specific DNA markers at VRN-H1 and VRN-H2 loci for growth habit of barley genotypes

Requirement of vernalization is an important factor which plays a crucial role in cereals to transit from vegetative to reproductive phase. There are three types of growth habit in barley: winter, spring and facultative types; in which spring type does not require vernalization but winter and facultative genotypes require full and partial vernalization, respectively. Combination of two loci, Vrn-h1 and Vrn-h2, regulates vernalization in barley genotypes. Specific DNA markers have been identified for growth habit regulator genes in barley. In this study, we examined 24 barley genotypes using specific primers for detecting Vrn-h1and Vrn-h2 loci. Results showed that among all differently suggested primer combinations, a few markers were precisely correlated with seasonal growth habit in barley. The specific markers of 600, 600 and 200 bps were verified for ZCCT-Ha, ZCCT-Hb and ZCCT-Hc loci, respectively. Our field growth habit test showed that cultivar Bahman as a winter growth habit, where all the others genotypes exhibited spring growth habit. By using specific primers for Vrn-h1, only Bahman cultivar produced 616 bp and 830 bp fragments and spring genotypes showed 574 bp or 616 bp alleles without any amplification for 830 bp fragments. Therefore, presence of 616 bp and 830 bp alleles together in each genotype can be considered as an informative marker for winter growth habit in barley. These informative markers can be used easily in barley breeding programmes for detection of growth habit types in the seedling stage.

Registration of ‘Buck’ Naked Barley

‘Buck’ (Reg. No. CV‐363, PI 682744) is a naked (hull‐less), six‐row barley (Hordeum vulgare L.) cultivar with winter growth habit. The cultivar was released by the Oregon Agricultural Experiment Station in 2015. The name Buck was chosen because the cultivar is naked. Prior to being named, Buck was tested under the experimental designation 09OR‐86. In high‐rainfall environments, it had a yield advantage over the naked check and had an excellent test weight. When grain yield was adjusted for the weight of hulls, Buck was competitive with all checks. Buck is resistant to barley stripe rust and moderately resistant to leaf rust. Buck was developed as a whole‐grain human food barley. However, multi‐use (e.g., food, malting, and feed) is an option. Feeding data are not available. Malting quality data indicate that Buck has higher malt extract than current covered (hulled) malting cultivars. Buck is the first naked winter cultivar to be released with adaptation to the US Pacific Northwest.

‘LA05006’, a Dual‐Purpose Oat for Louisiana and Other Southeastern Regions of the USA

‘LA05006’ (Reg. No. CV‐382, PI 678581), a winter‐type, dual‐purpose oat (Avena sativa L.) suited for grain and forage production, was codeveloped by Louisiana State University Agricultural Center and the University of Florida and was released in 2012 under the SunGrains cooperative small grain breeding program among six southeastern universities. Exclusive marketing rights were licensed to Plantation Seed Conditioner, Newton, GA, for sales under the name ‘Horizon 306’. This line was derived from a single cross, ‘Plot Spike LA9339’/’TAMO 405’, and was’ tested as LA05006GSBS‐65‐S1. LA05006 was developed using a selected bulk breeding method and was selected as an F5:6 head row. It was evaluated in preliminary, advanced, regional, and state grain and forage yield trials from 2010 to 2012. It is a midmaturing, medium to midtall oat with excellent forage yield and very good grain yield and test weight and also demonstrates excellent lodging resistance. LA05006 was observed to be uniform and stable from 2010 to present. It possesses a semiprostrate winter growth habit and has large leaves that are dark green in color. LA05006 is resistant to stem rust and has shown good resistance to crown rust. Average winter and spring forage yield of LA05006 was slightly higher than other popular dual‐purpose winter oat cultivars (‘Horizon 201’, ‘Horizon 270’, and Plot Spike LA9339) and was similar to ‘LA99016’. LA05006 has broad environmental adaptation and has performed well in Louisiana, Florida, Georgia, Texas, and Mississippi.

Development and characterization of a spring hexaploid wheat line with no functional VRN2 genes.

Key message The combination of three non-functional alleles of the flowering repressor VRN2 results in a spring growth habit in wheat. In temperate cereals with a winter growth habit, a prolonged exposure to low temperatures (vernalization) accelerates flowering. Before vernalization, the VRN2 locus plays a central role in maintaining flowering repression. Non-functional VRN2 alleles result in spring growth habit and are frequent in diploid wheat and barley. However, in hexaploid wheat, the effect of these non-functional VRN2 alleles is masked by gene redundancy. In this study, we developed a triple VRN2 mutant (synthetic vrn2-null) in hexaploid wheat by combining the non-functional VRN-A2 allele present in most polyploid wheats with a VRN-B2 deletion from tetraploid wheat, and a non-functional VRN-D2 allele from Aegilops tauschii (Ae. tauschii) (the donor of hexaploid wheat D genome). Non-vernalized vrn2-null plants flowered 118 days (P < 2.8E−07) earlier than the winter control, and showed a limited vernalization response. The functional VRN-B2 allele is expressed at higher levels than the functional VRN-D2 allele and showed a stronger repressive effect under partial vernalization (4 °C for 4 weeks), and also in non-vernalized plants carrying only a functional VRN-B2 or VRN-D2 in heterozygous state. These results suggest that different combinations of VRN-B2 and VRN-D2 alleles can be a used to modulate the vernalization response in regions with mild winters. Spring vrn2-null mutants have been selected repeatedly in diploid wheat and barley, suggesting that they may have an adaptative value and that may be useful in hexaploid wheat. Spring wheat breeders can use these new alleles to improve wheat adaptation to different or changing environments.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-016-2713-3) contains supplementary material, which is available to authorized users.

The Effects of Both Recent and Long-Term Selection and Genetic Drift Are Readily Evident in North American Barley Breeding Populations.

Barley was introduced to North America ∼400 yr ago but adaptation to modern production environments is more recent. Comparisons of allele frequencies among growth habits and spike (inflorescence) types in North America indicate that significant genetic differentiation has accumulated in a relatively short evolutionary time span. Allele frequency differentiation is greatest among barley with two-row vs. six-row spikes, followed by spring vs. winter growth habit. Large changes in allele frequency among breeding programs suggest a major contribution of genetic drift and linked selection on genetic variation. Despite this, comparisons of 3613 modern North American cultivated barley breeding lines that differ for spike-type and growth habit permit the discovery of 142 single nucleotide polymorphism (SNP) outliers putatively linked to targets of selection. For example, SNPs within the Cbf4, Ppd-H1, and Vrn-H1 loci, which have previously been associated with agronomically adaptive phenotypes, are identified as outliers. Analysis of extended haplotype sharing identifies genomic regions shared within and among breeding populations, suggestive of a number of genomic regions subject to recent selection. Finally, we are able to identify recent bouts of gene flow between breeding populations that could point to the sharing of agronomically adaptive variation. These results are supported by pedigrees and breeders’ understanding of germplasm sharing.

Identification of the VERNALIZATION 4 gene reveals the origin of spring growth habit in ancient wheats from South Asia

Wheat varieties with a winter growth habit require long exposures to low temperatures (vernalization) to accelerate flowering. Natural variation in four vernalization genes regulating this requirement has favored wheat adaptation to different environments. The first three genes (VRN1-VRN3) have been cloned and characterized before. Here we show that the fourth gene, VRN-D4, originated by the insertion of a ∼290-kb region from chromosome arm 5AL into the proximal region of chromosome arm 5DS. The inserted 5AL region includes a copy of VRN-A1 that carries distinctive mutations in its coding and regulatory regions. Three lines of evidence confirmed that this gene is VRN-D4: it cosegregated with VRN-D4 in a high-density mapping population; it was expressed earlier than other VRN1 genes in the absence of vernalization; and induced mutations in this gene resulted in delayed flowering. VRN-D4 was found in most accessions of the ancient subspecies Triticum aestivum ssp. sphaerococcum from South Asia. This subspecies showed a significant reduction of genetic diversity and increased genetic differentiation in the centromeric region of chromosome 5D, suggesting that VRN-D4 likely contributed to local adaptation and was favored by positive selection. Three adjacent SNPs in a regulatory region of the VRN-D4 first intron disrupt the binding of GLYCINE-RICH RNA-BINDING PROTEIN 2 (TaGRP2), a known repressor of VRN1 expression. The same SNPs were identified in VRN-A1 alleles previously associated with reduced vernalization requirement. These alleles can be used to modulate vernalization requirements and to develop wheat varieties better adapted to different or changing environments.

Developing Winter Food Barley for the Pacific Northwest of the US

ABSTRACTBarley (Hordeum vulgare L.) has been cultivated for human consumption for millennia. However, most North Americans do not regularly consume barley as a foodstuff. In the last decade, there has been renewed interest in barley production for human consumption. A number of quality traits are used to estimate nutritional value and are useful for food processing. These include β‐glucan, grain protein, kernel hardness, solvent retention capacity (SRC), and hull type. The Pacific Northwest (PNW) of the US is a high‐yielding region that has a reputation for setting dietary and nutritional trends. However, there are currently no winter food barleys adapted to this area. To determine the potential suitability of winter growth habits for food barley production in the PNW, we developed and tested 14 advanced lines. The germplasm was developed via marker‐assisted and phenotypic selection and included hulled lines with waxy starch and hull‐less lines with normal starch. Agronomic and food quality traits were measured on samples from three representative environments (dryland, irrigated, and high rainfall) over a 2‐yr period allowing for assessment of performance within and across locations, as well as genotype × environment interaction. Lines with waxy starch had significantly higher levels of β‐glucan, harder kernels, and higher water retention capacity. Hull‐less lines had, on average, slightly lower yields than hulled lines, with an average difference of 105 kg ha−1. Our future food barley variety development will focus exclusively on hull‐less types because of the simplified processing and consumer interest in the nutritional benefits of whole grain.

Distribution of the Vrn-D1b allele associated with facultative growth habit in Chinese wheat accessions

Vernalization requirement in wheat is determined by allelic variation mainly at three loci, Vrn-A1, Vrn-B1 and Vrn-D1. Up to 2011 only two alleles at the Vrn-D1 locus were known. The dominant allele, now designated as Vrn-D1a, confers spring growth habit, and the other, recessive allele, vrn-D1, is associated with the winter growth habit. Recently, we found an additional dominant allele, Vrn-D1b, associated with the facultative growth habit. As facultative wheat cultivars play an important role in wheat production we screened 689 accessions from all over China, with a specific aim of determining the frequency and distribution of Vrn-D1b. The results showed that Vrn-D1a, Vrn-D1b and vrn-D1 were present in 27.3, 20.6 and 52.1 % of all accessions, respectively. Vrn-D1a was mostly distributed in the autumn sown spring wheat zone, whereas Vrn-D1b was common in the autumn sown facultative wheat zone. One cultivar (Shiluan 02-1) was heterogeneous at the Vrn-D1 locus. A comparison between the Vrn-D1b genotype and the vrn-D1 genotype from the same cultivar showed that without vernalization the Vrn-D1b genotype reached the double ridge (DR) stage 27 days earlier than the vrn-D1 genotype. Vernalization responses, expressed as a reduction in the number of days to reach the DR stage following cold treatment, at 4 °C for 20, 30 and 40 days, were 62, 67 and 75 days, respectively, for the Vrn-D1b genotype, and 74, 87 and 98 days, respectively, for the vrn-D1 genotype, confirming the effect of Vrn-D1b on facultative growth habit. Pedigree analysis indicates that the Vrn-D1b allele originated from Chinese landraces.

Registration of #STRKR Barley Germplasm

#STRKR (Reg. No. GP-208, PI 674325) is a hulless, six-row barley (Hordeum vulgare L.) germplasm composed of the bulk of three full-sib lines, two of which have winter growth habit and one of which has facultative growth habit. The germplasm was released by the Oregon Agricultural Experiment Station in 2014. The three sister lines from the Oregon State University Barley Breeding Program that were bulked to form #STRKR were derived from the cross of F1(‘Maja’/‘Legacy’)/Maja/3/‘Doyce’. #STRKR was tested under the experimental designation Streaker. The #STRKR germplasm is uniform for spike type, rachilla hair length, resistance to stripe rust (incited by by Puccinia striiformis f. sp. hordei), and grain quality parameters. It is relatively uniform in terms of height and heading date. #STRKR is phenotypically heterogeneous for awn texture, grain color, and tolerance to scald (incited by Rhynchosporium commune). As a blend, #STRKR has shown winter survival comparable to Maja in environments where there was differential winter injury. #STRKR germplasm provides a resource for reselection and a parental source for disease resistance and quality parameters.