Plant & Animal Genome VI Conference

W100

GENOMICS AND MALTING QUALITY OF BARLEY: A NORTH AMERICAN PERSPECTIVE

Dept. of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164-6420, USA.

Comprehensive efforts in Canada and the USA on barley genomics has been coordinated by the North American Barley Genome Mapping Project (NABGMP). More than 40 scientists contributed to the research reported herein. Efforts have centered on molecular marker based genome map development, mapping of economically important qualitative and quantitative trait loci (QTL), genomics tool development, fine structure mapping, gene cloning, synteny studies, and breeding via marker assisted selection (MAS). Two major objectives are to understand the quantitative genetics of malting quality (MQ) and to utilize the knowledge for barley improvement through molecular breeding strategies. Research has focused on three crosses; "Steptoe"/"Morex" (6-row feed/6-row malting), "Harrington"/TR306 (2-row malting/2-row feed), and Harrington/Morex. F₁-derived doubled haploid mapping populations were developed and grown at multiple sites multiple years to gather field and laboratory data. First generation QTL analyses and verification studies have identified numerous chromosome regions throughout the barley genome that contain QTL for MQ traits including malt extract (ME), fine-coarse difference, alpha-amylase (AA), beta-amylase, and beta-glucanase (BGase) activities, diastatic power (DP), grain protein, wort protein, grain beta-glucan, and malt beta-glucan (BG) contents, extract viscosity, kernel weight and plumpness, and seed dormancy (Dor). Using marker assisted backcross isogenic lines and a saturated map, initial fine structure mapping of a 27 cM region on chromosome 1 containing coincident QTL for ME, AA, DP, BG, BGase and Dor has resolved several QTL into 1-8 cM fragments. MAS for MQ QTL was more effective compared with conventional phenotypic selection for a chromosome 1 QTL region, but not for a chromosome 4 QTL region. Studies thus far have revealed much new information about MQ QTL identification and trait relationships, but many questions remain about precise map locations, coincident QTL, single QTL inheritance, pleiotropy, epistasis, and GXE.