Submitted to: Molecular Breeding
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/17/2007
Publication Date: 10/7/2007
Citation: Chen, C., Cai, S., Bai, G. 2007. A major QTL controlling seed dormancy and pre-harvest sprouting resistance on chromosome 4A in a Chinese wheat landrace. Molecular Breeding. 21:351-358. Interpretive Summary: Germination of wheat kernels in a ripe wheat head before harvesting due to a long period of wet weather is called pre-harvest sprouting (PHS). PHS can cause significant reduction in wheat yield and grain quality worldwide. Wheat resistance to PHS can effectively reduce the PHS losses. Some Chinese wheat have been reported to be resistant to PHS. A gene from Chinese wheat Tutoumai A was identified through analysis of molecular markers. Twelve molecular markers were associated with the gene for PHS resistance and long seed dormancy. This gene was located on the long arm of chromosome 4A. Two molecular markers were close to the gene, and explained 30.6% of PHS resistance in Tutoumai A. Therefore, this gene is most likely the major gene for PHS resistance. The linked markers to the gene can be used for marker-assisted breeding for PHS-resistant white wheat cultivars.
Technical Abstract: Wheat pre-harvest sprouting (PHS) can cause significant reduction in yield and end-use quality of wheat grains in many wheat-growing areas worldwide. To identify quantitative trait locus (QTL) for PHS resistance in wheat, seed dormancy and sprouting of matured spikes were investigated in a population of 162 recombinant inbred lines (RILs) derived from a cross between a white PHS-resistant Chinese landrace Totoumai A and a white PHS-susceptible cultivar Siyang 936. After 1125 SSR primers were screened, 236 were polymorphic between parents, and used to screen the mapping population. Both seed dormancy and PHS of matured spikes were evaluated by the percentage of germinated kernels under controlled moist conditions. Twelve SSR markers associated with both PHS and seed dormancy were located on the long arm of chromosome 4A. One QTL for both seed dormancy and PHS resistance was detected on the chromosome 4AL. Two SSR markers, Xbarc 170 and Xgwm 397, are 9.14 cM apart, and flanked the QTL that explained 28.3% of the phenotypic variation for seed dormancy and 30.6% for PHS resistance. This QTL most likely contributed to both long seed dormancy period and enhanced PHS resistance. Therefore, this QTL is most likely responsible for both seed dormancy and PHS resistance. The linked SSR markers to the QTL can be used for marker-assisted selection for PHS-resistant white wheat cultivars.