Submitted to: Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 8, 2010
Publication Date: October 29, 2010
Repository URL:http://hdl.handle.net/10113/45695 Citation: Heng, Y., Foley, M.E., Gu, X. 2010. New seed dormancy loci detected from weedy rice-derived advanced populations with major QTL alleles removed from the background. Plant Science. 179:612-619.
Interpretive Summary: Seed dormancy is a key characteristic of weedy plants. We developed weedy rice as a model to identify genes (QTL) that regulate seed dormancy. Previously, we identified seven dormancy QTLs derived from a dormant line of weedy rice, which had been crossed and backcrossed to a nondormant breeding line of rice. In this research, we identified and confirmed three additional QTL using advanced populations. Additionally, we conclude that about 80% of the seed dormancy genes are eliminated during domestication and breeding activities.
Domestication of cereal crops from wild relatives tended to eliminate seed dormancy. Our objective was to identify all the detectable seed dormancy loci that differentiated between a weedy and a cultivated line of rice to understand the impact of domestication on distribution of dormancy genes. Three additional dormancy quantitative trait loci (QTL) were identified from two BC1F1 plant-derived F2 populations, in which the five previously known QTL-containing segments from the weedy rice donor were substituted by the genome of the recurrent parent. The three new QTL that accounted for 8-11% phenotypic variance in the F2s were confirmed with three BC1F2 plant-derived F3 populations. Counting the seven previously identified QTL, the parental lines differentiate at a total of 10 dormancy loci that vary in dominance from dominant, partially dominant, co-dominant, to recessive types. The weedy and cultivar parents contribute dormancy alleles to eight and two of the 10 loci, respectively. The two loci were newly detected. We concluded that a large proportion (8/10) of seed dormancy genes have been eliminated during domestication. The minor proportion (2/10) of dormancy genes retained in cultivars could be masked by those with a relatively large effect in a primary segregating population.