|ELIAS, ELIAS - North Dakota State University|
|BENSCHER, DAVID - Cornell University|
|ISHIKAWA, GORO - National Agriculture And Food Research Organization (NARO), Agricultrual Research Center|
|HUANG, YUNG - Agriculture And Agri-Food Canada|
|SAITO, MIKA - National Agriculture And Food Research Organization (NARO), Agricultrual Research Center|
|NAKAMURA, TOSHIKI - National Agriculture And Food Research Organization (NARO), Agricultrual Research Center|
|SORRELLS, MARK - Cornell University|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2015
Publication Date: 12/30/2015
Publication URL: http://handle.nal.usda.gov/10113/61795
Citation: Chao, S., Elias, E., Benscher, D., Ishikawa, G., Huang, Y.-F., Saito, M., Nakamura, T., Xu, S., Faris, J., Sorrells, M. 2016. Genetic mapping of major-effect seed dormancy quantitative trait loci on chromosome 2B using recombinant substitution lines in tetraploid wheat. Crop Science. 56:59-72.
Interpretive Summary: Pre-harvest sprouting (PHS) refers to germination of grain in the ear prior to harvesting under wet field conditions. PHS damage often leads to a reduction in both grain yield and grain quality. Seed dormancy, the main factor contributing to PHS tolerance, is a trait with complex inheritance and strongly influenced by environmental growth conditions. Wild emmer, a close relative of cultivated durum wheat, is known to be a rich source of genetic variation for disease resistance and end-use grain quality. In this study, we identified genes controlling seed dormancy located on chromosome 2B originating from wild emmer. Genetic lines carrying the genes tended to have higher seed dormancy levels than those without them. Therefore, the genes identified in this study should be useful for improving PHS tolerance in durum wheat.
Technical Abstract: Durum wheat cultivars can benefit from having some level of seed dormancy to help reduce seed damage and lower grain quality caused by pre-harvest sprouting (PHS) occurring during wet harvesting conditions. Previously a single chromosome substitution line carrying chromosome 2B of wild emmer in the durum cultivar ‘Langdon’ background was found to have higher levels of seed dormancy and PHS tolerance. In this study, a population of recombinant substitution lines was developed and used to construct a SNP-based high density genetic linkage map. Seed germination tests were used to evaluate seed dormancy levels of the population grown in five field environments. Multiple interval mapping analysis revealed six QTL regions affecting seed dormancy. Two regions containing major-effect QTL contributed by wild emmer were consistently expressed in four environments and explained 5.89 to 11.14% of the phenotypic variation. One QTL region was located near the centromere and the other on the long arm of chromosome 2B in Bayes credible intervals of 4 and 7 cM, respectively. The two QTL regions identified in this study should be useful for improving PHS tolerance in wheat. Efforts to transfer the two QTL into elite durum cultivars are in progress to examine the effects of genetic background and environment on QTL expression and to evaluate the performance of other agronomic traits in the presence of the QTL.