Location: Hard Winter Wheat Genetics ResearchTitle: Quantitative trait loci for resistance to pre-harvest sprouting in U.S. hard white winter wheat) Author
Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/21/2008
Publication Date: 7/20/2008
Citation: Liu, S., Cai, S., Graybosch, R.A., Chen, C., Bai, G. 2008. Quantitative trait loci for resistance to pre-harvest sprouting in U.S. hard white winter wheat. Journal of Theoretical and Applied Genetics. 117:691-699. Interpretive Summary: Pre-harvesting sprouting (PHS) refers to seed germination in a matured wheat head before harvest due to a long period wet weather. Sprouted wheat usually has poor flour quality. Using DNA marker technology, three genetic factors, called quantitative trait loci (QTL), that control delayed seed germination were identified from US white wheat cultivar Rio Blanco. One major QTL, QPhs. pseru-3A, was identified in the distal region of wheat chromosome 3AS and was responsible for 41.0% PHS resistance based on three greenhouse experiments. This QTL was identified in two mapping populations with Rio Blanco as the PHS-resistant parent. Two other QTL were located on chromosome 2B and showed a minor effect on PHS resistance. These QTLs were tagged with several DNA markers. Because Rio Blanco is a popular parent used in many hard winter wheat breeding programs, DNA markers linked to the QTLs have potential for use in marker-assisted selection of wheat cultivars with improved PHS resistance
Technical Abstract: Pre-harvesting sprouting (PHS) of wheat is a major problem that severely limits the end-use quality of flour in many wheat-growing areas worldwide. To identify quantitative trait loci (QTLs) for PHS resistance, a population of 171 recombinant inbred lines (RILs) was developed from the cross between PHS-resistant white wheat cultivar Rio Blanco and PHS-susceptible white wheat breeding line NW97S186. The population was evaluated for PHS in three greenhouse experiments and one field experiment. After 1430 pairs of simple sequence repeat (SSR) primers were screened between the two parents and two bulks, 112 polymorphic markers between two bulks were used to screen the RILs. One major QTL, QPhs. pseru-3A, was identified in the distal region of chromosome 3AS and explained up to 41.0% of the total phenotypic variation in three greenhouse experiments. One minor QTL, QPhs.pseru- 2B.1, was detected in the 2005 and 2006 experiments and for the means over the greenhouse experiments, and explained 5.0% to 6.4% of phenotypic variation. Another minor QTL, QPhs.Pseru-2B.2, was detected in only one greenhouse experiment and explained 4.5% of phenotypic variation for PHS resistance. In another RIL population developed from the cross of Rio Blanco x NW97S078, QPhs.pseru-3A was significant for all three greenhouse experiments and the means over all greenhouse experiments and explained up to 58.0% of phenotypic variation. Because Rio Blanco is a popular parent used in many hard winter wheat breeding programs, SSR markers linked to the QTLs have potential for use in high-throughput marker-assisted selection of wheat cultivars with improved PHS resistance as well as fine mapping and map-based cloning of the major QTL QPhs.pseru-3A.