|Kirigwi, Francis - KANSAS STATE UNIVERSITY|
|Van Ginkel, Martin - DPI HORSHAM VIC AUSTRALIA|
|Gill, Bikram - KANSAS STATE UNIVERSITY|
|Paulsen, Gary M - KANSAS STATE UNIVERSITY|
|Fritz, Allan - KANSAS STATE UNIVERSITY|
Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2007
Publication Date: November 1, 2007
Citation: Kirigwi, F.M., Van Ginkel, M., Brown Guedira, G.L., Gill, B.S., Paulsen, G., Fritz, A.K. 2007. Markers associated with a qtl for grain yield in wheat under drought. Molecular Breeding. 20(4):401-403. Interpretive Summary: Wheat production is adversely affected by drought in 50% of the area under production in the developing and 70% in the developed countries. Genetic improvement for yield in these environments is estimated at about half of the yield under well-watered environments. Grain yields range from 10 to 50% of their irrigated potential. In this study, we analyzed the drought tolerance in a population from a cross between common wheat varieties ‘Dharwar Dry’ (drought tolerant) and ‘Sitta’. A genetic map was also constructed using DNA markers. Analysis of these data identified a chromosome region from Dharwar Dry that had positive effects on grain yield and yield components under drought stress. This resulted in identification of DNA markers or tags for drought tolerance that can be used by wheat breeders to select varieties with improved performance under drought.
Technical Abstract: Drought is a major abiotic stress that adversely affects wheat production in many regions of the world. The objective of this study was to identify quantitative trait loci (QTL) controlling grain yield and yield components under reduced moisture. A cross between common wheat cultivars ‘Dharwar Dry’ (drought tolerant) and ‘Sitta’ was the source of one hundred twenty-seven recombinant inbred lines evaluated for two-seasons in a field under differing soil moisture regimes in Ciudad Obregon, Sonora, Mexico. An SSR/EST-STS marker map was constructed and a grain yield QTL on the proximal region of chromosome 4AL was found to have a significant impact on performance under reduced moisture. This region was associated with QTL for grain yield, grain fill rate, spike density, grains m-2, biomass production, biomass production rate, and drought susceptibility index (DSI). Molecular markers associated with these traits explained 20, 33, 15, 23, 30, 26, and 41% of phenotypic variation, respectively. Microsatellite locus Xwmc89 was associated with all significant QTL covering a 7.7 cM region and generally explained the greatest proportion of phenotypic variation. The alleles associated with enhanced performance under drought stress were contributed by Dharwar Dry. Microsatellite marker wmc89 may be useful for marker assisted selection to enhance drought tolerance.