USDA-ARS National Small Grains Research Articles

Genome‐wide mapping of resistance to stripe rust caused by Puccinia striiformis f. sp. tritici in hexaploid winter wheat

AbstractStripe rust, caused by the fungus Puccinia striiformis f. sp. tritici (Pst), is a widespread disease and major limit to wheat (Triticum aestivum L.) production worldwide. The USDA‐ARS National Small Grains Germplasm Collection has proven to be a rich source of genetic diversity to improve stripe rust resistance in wheat breeding programs. The objective of the present study was to investigate the genetic diversity and sources of resistance to stripe rust in 441 accessions from the collection representing globally sourced winter wheat germplasm, as a complement to a previous study. A genome‐wide association study was conducted to identify loci conferring resistance to Pst based on phenotypic data from four field experiments and greenhouse seedling resistance screening against three races of the pathogen. A total of 5831 single nucleotide polymorphism markers were used to investigate population structure, linkage disequilibrium, and marker–trait associations. Our results showed 12 and 7 genomic regions significantly associated with Pst resistance based on field adult‐plant and greenhouse seedling responses, respectively, at a false discovery rate adjusted P value of <0.1. Four of the significantly associated genomic regions were mapped far from previously identified Pst resistance genes and quantitative trait loci, indicating that they represent potentially new Pst resistance loci. The present study provides additional insight into the usefulness of wheat germplasm collections as an important resistance source that can be used to incorporate diverse resistance genes into adapted wheat cultivars. Further work should aim to validate the identified genomic regions and the associated molecular markers to enhance their utility in marker‐assisted breeding.

Evaluation of Agronomic Traits and Drought Tolerance of Winter Wheat Accessions from the USDA-ARS National Small Grains Collection

Wheat accessions from the USDA-ARS National Small Grains Collection (NSGC) are a potential genetic resource for variety improvement. This study assessed the agronomic performance and drought tolerance in 198 winter wheat accessions under irrigated and terminal drought environments in the 2012–2013 season, and repeated the test under terminal drought only during the 2013–2014 season. The 198 accessions were classified into three maturity groups, early, intermediate, and late based on heading data. In all three environments, the early accessions had the best agronomic performance, produced higher grain yield, thousand-kernel weight and grain volume weight, and had earlier heading date and shorter plant height. The intermediate accessions had similar grain yield and thousand-kernel weight as the early accessions in the irrigated environment, but had lower thousand-kernel weight in the terminal drought environments. Terminal drought had significant effects on grain yield, plant height, thousand-kernel weight, and grain volume weight. The positive correlation between GY and HD suggests that the ‘late early’ types in the early maturity were the most successful. Out of 198 accessions evaluated, twenty-three had high yield stability and drought tolerance according to the drought susceptibility index and membership function value of drought tolerance. The eight of twenty-three accessions identified (four early and four intermediate) had high grain yield in three environments. Some of these accessions have been further used in bi-parental mapping studies and by breeders for grain yield and drought tolerance improvement.

Evaluation of Genetic Diversity and Host Resistance to Stem Rust in USDA NSGC Durum Wheat Accessions.

The USDA-ARS National Small Grains Collection (NSGC) maintains germplasm representing global diversity of small grains and their wild relatives. To evaluate the utility of the NSGC durum wheat ( L. ssp. ) accessions, we assessed genetic diversity and linkage disequilibrium (LD) patterns in a durum core subset containing 429 lines with spring growth habit originating from 64 countries worldwide. Genetic diversity estimated using wheat single-nucleotide polymorphism (SNP) markers showed considerable diversity captured in this collection. Average LD decayed over a genetic distance to within 3 cM at = 0.2, with a fast LD decay for markers linked at >5 cM. We evaluated accessions for resistance to wheat stem rust, caused by a fungal pathogen, Pers. Pers. f. sp. Eriks. and E. Henn (), using races from both eastern Africa and North America, at seedling and adult plant stages. Five accessions were identified as resistant to all stem rust pathogen races evaluated. Genome-wide association analysis detected 17 significant associations at the seedling stage with nine likely corresponding to , , and and the remaining potentially being novel genes located on six chromosomes. A higher frequency of resistant accessions was found at the adult plant stage than at the seedling stage. However, few significant associations were detected possibly a result of strong G × E interactions not properly accounted for in the mixed model. Nonetheless, the resistant accessions identified in this study should provide wheat breeders with valuable resources for improving stem rust resistance.

Genetic Diversity for Russian Wheat Aphid Resistance as Determined by Genome‐Wide Association Mapping and Inheritance in Progeny

ABSTRACTRussian wheat aphid (RWA) [Diuraphis noxia (Mordvilko)] is an increasing problem on barley (Hordeum vulgare L.) throughout the world. Genetic resistance has been identified and used to create barley germplasm and cultivars adapted to the United States. Several mapping studies have been conducted to identify loci associated with resistance, but questions remain, particularly regarding the extent of genetic diversity among resistance sources and improved lines and cultivars. Association analysis of resistant (R) and moderately resistant (MR), unadapted accessions held in the USDA–ARS National Small Grains Germplasm Collection, adapted germplasm lines derived from these accessions, and susceptible (S) elite cultivars was conducted using 4509 single nucleotide polymorphisms (SNPs) to identify markers linked to resistance. Resistance was associated with loci on chromosomes 1H, 2H, 3H, 5H, and 7H at p‐values <0.0001, and the major 1H and 3H loci identified in previous tests were confirmed. However, the genetics of RWA resistance was shown to be complex, and it is likely that loci involved in resistance in some lines were not identified. Nevertheless, this analysis identified diversity among R lines and showed that most of the released RWA‐resistant cultivars had similar genotypes at loci associated with resistance. This analysis also identified R lines that were genetically dissimilar to the released cultivars at these loci. This information can guide parental selection for future breeding efforts designed to capture and deploy greater diversity for RWA resistance among new barley cultivars.

Evaluating Grain Yield in Spring Wheat with Canopy Spectral Reflectance

ABSTRACTWorldwide, improving grain yield is the most important target for wheat (Triticum aestivum L.) breeders. Fast, cost‐effective, and nondestructive phenotyping methods for important traits are needed to increase the efficiency of cultivar development. The present study tested canopy spectral reflectance (CSR) as a potential high‐throughput method for assessing wheat grain yield in a diverse set of 540 spring‐habit accessions from the USDA–ARS National Small Grains Collection. Plots were grown under irrigated (IR) and terminal drought (DR) treatments over two growing seasons, and CSR was measured at several growth stages in each year. The CSR indices related to canopy water and N status, biomass, and photosynthetic area were evaluated for their relation to grain yield. The CSR indices were significantly correlated with yield at every growth stage, with anthesis and grain filling being the most useful for predicting grain yield in IR and DR environments. Single CSR indices selected up to 57% of the highest 25% yielding lines in DR conditions and the grain yield of accessions selected using CSR was 20% greater than randomly selected genotypes. Canopy spectral reflectance also identified up to 86% of the highest 10% yielding accessions. Canopy spectral reflectance may be valuable as a high‐throughput means of selecting for yield in large trials of genetically diverse wheat genotypes.

Genetic Diversity among Wheat Accessions from the USDA National Small Grains Collection

ABSTRACTAccessions of common wheat (Triticum aestivum L. subsp. aestivum) from the USDA–ARS National Small Grains Collection (NSGC) are a resource for wheat scientists worldwide. The genetic diversity of the wheat core subset, representing approximately 10% of the collection's 42,138 T. aestivum accessions, was examined using 390 diversity arrays technology (DArT) markers, 4941 single nucleotide polymorphisms (SNPs), and descriptor data. The marker profiles revealed duplicates, which were excluded to form an informative core (iCore) of 3230 accessions. The iCore population structure and diversity within various subgroups were examined with analysis of molecular variance, principal coordinate analysis, cluster analysis, and by ranking the contribution of individual accessions to overall diversity. Accession groups based on molecular marker data corresponded well to their geographic origin, and population structure was accounted for primarily by differences between Iranian landrace accessions and the rest of the accessions. Accessions classified as breeding lines were overrepresented among those ranked as most diverse based on SNP data, whereas Iranian landraces were underrepresented. Although less diverse as a group, Iranian landrace accessions had a higher frequency of resistance to bunt diseases and Russian wheat aphid compared with the iCore as a whole. The present study provides support for establishing core subsets based on geographic origin of accessions and will be a basis for further study of diversity among NSGC wheats.

Seedling resistance to Puccinia coronata f. sp. avenae in Avena strigosa, A. barbata and A. sativa

A study was carried out in which seedling resistance to the crown rust pathogen, Puccinia coronata f. sp. avenae (Pca), was characterised among 385 oat accessions of Avena strigosa, A. barbata and A. sativa from the USDA-ARS National Small Grains Collection. Accessions were tested with eight Austra- lian pathotypes of Pca of diverse pathogenicity on a series of differential genotypes carrying known seedling resistance genes. Three diploid accessions, CIav2524, PI78821 and PI83721 of A. strigosa, were highly resistant to all eight Pca pathotypes, and were postulated to carry Pc50 and Pc68, Pc91, or one or more new resistance genes. A total of 58 unidentified resistance specificities were detected among the tetraploid A. barbata accessions. All 58 resistances were ineffective against at least one of the Pca pathotypes and could therefore be novel. Additionally, evidence was obtained for the presence of genes Pc39 and Pc52 (in A. barbata and A. sativa accessions), Pc45 (in A. barbata accessions), Pc94 (in A. strigosa and A. barbata accessions) and the ''Saia'' resistance (in A. strigosa accessions).

The use of microsatellite polymorphisms to characterise and compare genetic variability in Avena strigosa and A. barbata

Microsatellite (SSR) polymorphism was assessed across 90 diploid Avena strigosa Schreb. and tetraploid Avena barbata Pott ex Link accessions obtained from the USDA-ARS National Small Grains Collection using 105 genomic SSRs. Eleven polymorphic SSRs that detected 69 different alleles were identified and used to genotype the 90 accessions, which were chosen from a larger set of 385 accessions based on geographical source-diversity and variable reaction responses to five Australian pathotypes of the crown rust pathogen Puccinia coronata Corda f. sp. avenae Eriks. Eight diploid and eight tetraploid clades were identified among the 90 accessions. Diploid accessions displayed the lowest genetic diversity, with all accessions being at least 86 % similar, and included accessions from countries in the Americas such as Canada, USA, Argentina, Uruguay and Brazil, and European accessions from France, Romania and Poland. Although both species formed distinct clusters in the dendrogram, a few instances of diploids showing high similarity with tetraploids and vice versa were observed. An AMOVA analysis revealed 86 % of the total genetic variation to be distributed within the two oat species, while between-species differences accounted for only 14 %. Heterozygosity (H) index values of 0.32 and 0.40 were obtained for diploids and tetraploids respectively. Our study effectively differentiated A. strigosa and A. barbata, and identified 11 SSRs suitable for future characterisation of accessions of the two species.

Identification of novel genomic regions associated with resistance to Pyrenophora tritici-repentis races 1 and 5 in spring wheat landraces using association analysis

Tan spot, caused by Pyrenophora tritici-repentis, is a major foliar disease of wheat worldwide. Host plant resistance is the best strategy to manage this disease. Traditionally, bi-parental mapping populations have been used to identify and map quantitative trait loci (QTL) affecting tan spot resistance in wheat. The association mapping (AM) could be an alternative approach to identify QTL based on linkage disequilibrium (LD) within a diverse germplasm set. In this study, we assessed resistance to P. tritici-repentis races 1 and 5 in 567 spring wheat landraces from the USDA-ARS National Small Grains Collection (NSGC). Using 832 diversity array technology (DArT) markers, QTL for resistance to P. tritici-repentis races 1 and 5 were identified. A linear model with principal components suggests that at least seven and three DArT markers were significantly associated with resistance to P. tritici-repentis races 1 and 5, respectively. The DArT markers associated with resistance to race 1 were detected on chromosomes 1D, 2A, 2B, 2D, 4A, 5B, and 7D and explained 1.3-3.1% of the phenotypic variance, while markers associated with resistance to race 5 were distributed on 2D, 6A and 7D, and explained 2.2-5.9% of the phenotypic variance. Some of the genomic regions identified in this study correspond to previously identified loci responsible for resistance to P. tritici-repentis, offering validation for our AM approach. Other regions identified were novel and could possess genes useful for resistance breeding. Some DArT markers associated with resistance to race 1 also were localized in the same regions of wheat chromosomes where QTL for resistance to yellow rust, leaf rust and powdery mildew, have been mapped previously. This study demonstrates that AM can be a useful approach to identify and map novel genomic regions involved in resistance to P. tritici-repentis.

Screening USDA-ARS Wheat Germplasm for Bird Cherry-Oat Aphid Tolerance

The bird cherry-oat aphid (Rhopalosiphum padi L.) can cause significant yield reduction in wheat (Triticum aestivum L.) without causing aboveground visual damage symptoms. This lack of obvious aboveground symptom development makes it difficult to use standard aphid tolerance testing protocols, which are very effective in testing wheat for tolerance to other aphids. This study utilized an alternative screening method, using clear germination pouches, to assess the effects on both root and shoot development following aphid feeding as a way to deduce aphid feeding tolerance. Over 4,000 wheat accessions from the USDA-ARS National Small Grains Collection were evaluated. Qualitative ratings were determined by comparing wheat accession infested with bird cherry-oat aphids against the control (noninfested treatment). Following the infestation treatment, 17 accessions showed no dramatic decreases in root and shoot growth. Accessions identified are of considerable interest to those wheat breeding programs where bird cherry-oat aphid tolerance is an objective.

Registration of USG 3209/Jaypee Wheat Recombinant Inbred Line Mapping Population

‘USG 3209’/‘Jaypee’ (Reg. No. MP‐3, NSL 465777 MAP), is a soft red winter wheat (Triticum aestivum L.) recombinant inbred line (RIL) population developed by Virginia Polytechnic Institute and State University and submitted to the USDA–ARS National Small Grains Germplasm Research Facility in Aberdeen, ID, in 2008. This mapping population is composed of 130 F11:12 RILs and has been used to study the genetics of adult plant resistance to powdery mildew [Blumeria graminis (DC) E.O. Speer] and leaf rust (Puccinia triticina Eriks.), and soft winter wheat milling and baking quality. Genetic linkage maps of this population were created to identify quantitative trait loci governing these traits. The genetic marker data collected on this population has been submitted to the GrainGenes database (http://wheat.pw.usda.gov) and includes data from both microsatellite and Diversity Array Technology markers.

Registration of ‘Choptank’ Wheat

Crop ScienceVolume 46, Issue 1 p. 474-476 Registrations of Cultivar Registration of ‘Choptank’ Wheat J.M. Costa, Corresponding Author J.M. Costa [email protected] Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Corresponding author ([email protected])Search for more papers by this authorC.A. Griffey, C.A. Griffey Crop and Soil Environmental Sciences Dep., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA, 24061Search for more papers by this authorH.E. Bockelman, H.E. Bockelman USDA-ARS National Small Grains Germplasm Research Facility, Aberdeen, ID, 83210Search for more papers by this authorS.E. Cambron, S.E. Cambron Dep. of Entomology, USDA-ARS, Purdue Univ., W. Lafayette, IN, 47907Search for more papers by this authorX. Chen, X. Chen USDA-ARS-Washington State, Pullman, WA, 99164-6430Search for more papers by this authorA. Cooper, A. Cooper Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Search for more papers by this authorC. Gaines, C. Gaines USDA-ARS Soft Wheat Quality Lab, Wooster, OH, 44691Search for more papers by this authorR.A. Graybosch, R.A. Graybosch USDA-ARS Wheat, Sorghum & Forage Research, Lincoln, NE, 68583-0915Search for more papers by this authorA. Grybauskas, A. Grybauskas Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Search for more papers by this authorR.J. Kratochvil, R.J. Kratochvil Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Search for more papers by this authorD.L. Long, D.L. Long USDA-ARS Cereal Disease Lab, St. Paul, MN, 55108Search for more papers by this authorE. Shirley, E. Shirley Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Search for more papers by this authorL. Whitcher, L. Whitcher USDA-ARS, Plant Science Research Unit, Raleigh, NC, 27695Search for more papers by this author J.M. Costa, Corresponding Author J.M. Costa [email protected] Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Corresponding author ([email protected])Search for more papers by this authorC.A. Griffey, C.A. Griffey Crop and Soil Environmental Sciences Dep., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA, 24061Search for more papers by this authorH.E. Bockelman, H.E. Bockelman USDA-ARS National Small Grains Germplasm Research Facility, Aberdeen, ID, 83210Search for more papers by this authorS.E. Cambron, S.E. Cambron Dep. of Entomology, USDA-ARS, Purdue Univ., W. Lafayette, IN, 47907Search for more papers by this authorX. Chen, X. Chen USDA-ARS-Washington State, Pullman, WA, 99164-6430Search for more papers by this authorA. Cooper, A. Cooper Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Search for more papers by this authorC. Gaines, C. Gaines USDA-ARS Soft Wheat Quality Lab, Wooster, OH, 44691Search for more papers by this authorR.A. Graybosch, R.A. Graybosch USDA-ARS Wheat, Sorghum & Forage Research, Lincoln, NE, 68583-0915Search for more papers by this authorA. Grybauskas, A. Grybauskas Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Search for more papers by this authorR.J. Kratochvil, R.J. Kratochvil Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Search for more papers by this authorD.L. Long, D.L. Long USDA-ARS Cereal Disease Lab, St. Paul, MN, 55108Search for more papers by this authorE. Shirley, E. Shirley Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742-4452Search for more papers by this authorL. Whitcher, L. Whitcher USDA-ARS, Plant Science Research Unit, Raleigh, NC, 27695Search for more papers by this author First published: 01 January 2006 https://doi.org/10.2135/cropsci2005.04-0026Citations: 4 Registration by CSSA. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume46, Issue1January–February 2006Pages 474-476 RelatedInformation

Registration of ‘Tribute’ Wheat

Registration of ‘Tribute’ Wheat

Detection of Virulence to Wheat Stem Rust Resistance Gene Sr31 in Puccinia graminis. f. sp. tritici in Uganda.

In much of the world, resistance to stem rust in wheat, caused by Puccinia graminis f. sp. tritici, is based at least in part on the gene Sr31. During February 1999, high levels of stem rust infection were observed on entries in wheat (Triticum aestivum) grown in a nursery at Kalengyere Research Station in Uganda. Because several of the rusted entries were known to carry the 1BL-1RS chromosome translocation containing the Sr31, Lr26, and Yr9 genes for rust resistance, virulence to Sr31 was suspected. Urediniospores, collected in bulk from rusted stems of seven entries containing Sr31, were suspended in light mineral oil and sprayed on primary leaves of 7-day-old seedlings of South African wheat cv. Gamtoos (=Veery #3, pedigree: Kvz/Buho'S'//Kal/BB). Plants were kept overnight at 19 to 21°C in a dew chamber before placement in a greenhouse at 18 to 25°C. After ≈14 days, urediniospores were collected from large, susceptible-type stem rust pustules and subsequently increased on Gamtoos, which served as a selective host for the new rust culture, designated Pgt-Ug99. Pathogenicity of Pgt-Ug99 was studied in seedling tests of available wheats containing Sr31, as well as other stem rust differential lines. All seedling tests were conducted at least three times in independent inoculations. Isolate Pgt-Ug99 was not virulent to Avocet'S'/Yr9 (Australian line containing Sr26) or Oom Charl (South African cultivar) but was virulent to the other Sr31 testers: Alondra 'S', Bobwhite, Chokka, Clement, Federation/Kavkaz, Gamtoos, Grebe, Kavkaz, Letaba, Line E/Kavkaz, RL6078, and Veery 'S'. Virulence to Sr31 (infection types [ITs] 3-3 to 3++4) was clearly contrasted by the low reactions (ITs 0; to 1) produced by UVPgt53, a South African pathotype avirulent to Sr31. According to the reactions of the differential lines, Pgt-Ug99 is avirulent to Sr21, -22, -24, -25, -26, -27, -29, -32, -33, -34, -35, -36, -39, -40, -42, and -43, Agi, and Em and virulent to Sr5, -6, -7b, -8a, -8b, -9b, -9e, -9g, -11, -15, -17, -30, -31, and -38. Virulence to the T. ventricosum-derived gene Sr38, which is linked to Lr37 and Yr17 and occurs in cultivars from Australia, the United Kingdom, and the United States, was not known previously (1). Both Pgt-Ug99 and UVPgt53 produced a continuum of ITs (; to 2+3) on Petkus rye (obtained from the USDA-ARS National Small Grains Collection, Aberdeen, ID), the original Sr31 donor source. Pgt-Ug99 did not appear more virulent than UVPgt53 on Petkus. All triticales tested, as well as oat cv. Overberg, were highly resistant to Pgt-Ug99. According to McIntosh et al. (1), Huerta-Espino mentioned a Sr31-virulent culture from Turkey, but this could not be confirmed. Should the Sr31-virulent pathotype migrate out of Uganda, it poses a major threat to wheat production in countries where the leading cultivars have resistance based on this gene. Reference: (1) R. A. McIntosh et al. 1995. Wheat Rusts: An Atlas of Resistance Genes. Kluwer Academic Publishers, Dordrecht, the Netherlands.

Registration of Orchardgrass Germplasms KY 07G23‐334 and KY 07G23‐336

Winter barley (Hordeum vulgare L.) selection 88Ab536-B (Reg. no. GP-133, PI 595789) was developed cooperatively by the USDA-ARS and the Idaho Agric. Exp. Stn. It was approved for release as germplasm by the Univ. of Idaho Foundation Seed Stocks Committee in December 1995 on the basis of its superior malting quality compared with existing six-rowed winter barleys. The six-rowed winter barley selection 88Ab536 originated at Aberdeen, ID, as an Fe head row from the cross NE 76129/2* 'Morex' (made at Beltsville, MD). The FI through Fe generations were grown at the Univ. of Idaho Aberdeen Res. & Ext. Or. and selections were made in the FI through Fe generations. 88Ab536 has been tested in replicated trials in Idaho since 1989, and in the Western Winter Barley Nursery and the Uniform Barley Winterhardiness Nursery over a wide range of U.S. environments. Selection 88Ab536-B is a breeder seed composite of 36 reselections from 88Ab536 that were grown in a nonreplicated trial at Aberdeen and selected for morphological uniformity, maintaining favorable malting quality. 88Ab536-B is more uniform than 88AB536, and it has only lax spikes with rough awns, whereas 88Ab536 has a low frequency of dense spikes. It is relatively early maturing. Kernels have a white aleurone and long rachilla hairs. In four station-years of testing in irrigated trials at Aberdeen from 1989-1990 to 1993-1994, the yield of 88Ab536 (or 88Ab536-B) averaged 8364 kg ha~', or 78% of 'Eight-Twelve' and 87% of 'Schuyler'; the three barleys were similar in test weight and lodging resistance. Selection 88Ab536 averaged 5 cm taller than Schuyler and 10 cm taller than Eight-Twelve. It headed 5 d earlier than Eight-Twelve and 10 d earlier than Schuyler. EightTwelve and Schuyler are important feed barley varieties, but not suitable for malting and brewing. In irrigated trials at Aberdeen in 1993-1994 and 1995-1996, 88Ab536-B averaged 104% of the yield of the European six-rowed malting barley 'Plaisant'. 88Ab536-B has superior malting quality compared with other six-rowed winter cultivars such as Plaisant and Wintermalt, with an overall malting quality pattern similar to that of the recurrent spring parent, Morex (Table 1). Morex is the designated malting quality standard for six-rowed malting barley in the USA. Compared with other winter malting types, 88Ab536-B is markedly improved in having higher malt extract percentage, higher diastatic power and a-amylase activity, and lower fine-coarse (F/C) difference. Seed is available in small quantities for breeding and research purposes from the USDA-ARS National Small Grains Germplasm Research Facility, P.O. Box 307, Aberdeen, ID 83210.