Submitted to: Theoretical and Applied Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/14/2009
Publication Date: 12/4/2009
Citation: Munoz-Amatriain, M., Cistue, L., Xiong, Y., Bilgic, H., Budde, A.D., Schmitt, M., Smith, K., Hayes, P.M., Muehlbauer, G. 2009. Structural and Functional Characterization of a Winter Malting Barley. Theoretical and Applied Genetics. 120:971-984. Interpretive Summary: Winter barley varieties are planted in farmer’s fields in the fall where they overwinter and resume growth in the spring as the fields warm, contrasting with the more commonly grown spring barley varieties that are planted in the field in the spring. Winter barleys have a number of advantages compared to spring barleys, but must be able to withstand exposure to harsh winter conditions and resume vigorous growth in the spring. Varieties that are susceptible to winter damage will suffer stand reductions, yield less, and provide a poor economic return to the farmer, negating other potential advantages of the winter habit. Genetic control of the winterhardiness of a barley line is complex, as is the genetic control of traits that determine the malting quality. Combining both winterhardiness and malting quality traits in a single line to produce a variety than can overwinter in the field, but still produce grain that meets rigorous malting quality standards is a much greater challenge than producing a line that meets only one of those hurdles. In this study of the genetics and performance of two related lines, one of which is common benchmark for malting quality and the other that is derived from it but has desirable winterhardiness traits as well, we provide fundamental understanding of those two characteristics and their interactions that will assist development of additional cold-tolerant lines that also produce grain that meets malting quality requirements. Development of such lines will provide additional opportunities for economic return to barley growers as well as strengthening the supply of US-grown malting barley for the malting and brewing industries.
Technical Abstract: The development of winter malting barley (Hordeum vulgare L.) varieties is emerging as a worldwide priority due to the numerous advantages of these varieties over spring types. However, the complexity of both malting quality and winter hardiness phenotypes makes simultaneous improvement a challenge. To obtain an understanding of the relationship between loci controlling winter hardiness and malt quality and to assess the potential for breeding winter malting barley varieties, we structurally and functionally characterized the six-row genotype “88Ab536”, a cold-tolerant line with superior malting quality characteristics that derives from the cross of NE76129/Morex//Morex. We used 4,596 SNP to construct the haplotype structure of 88Ab536 on which malting quality and winter hardiness loci reported in the literature were aligned. The genomic regions determining malting quality and winter hardiness traits have been defined in this founder germplasm, which will assist breeders in targeting regions for marker-assisted selection. The Barley1 GeneChip array was used to functionally characterize 88Ab536 during malting. Its gene expression profile was similar to that of the archetypical malting variety Morex. The characterization of 88Ab536 has increased our understanding of the genetic relationships of malting quality and winter hardiness, and will provide a genetic foundation for further development of more cold-tolerant varieties that have malt quality characteristics that meet or exceed current benchmarks.