Reference "Phenotypic selection for dormancy introduced a set of adaptive haplotypes from weedy into cultivated rice"

Reference ID

11018

Title

Phenotypic selection for dormancy introduced a set of adaptive haplotypes from weedy into cultivated rice

Source

Genetics, 2005, vol. 171, pp. 695-704

Authors (3)

Gu-X-Y	Kianian-S-F
Foley-M-E

Abstract

Association of seed dormancy with shattering, awn, and black hull and red
pericarp colors enhances survival of wild and weedy species, but challenges the
use of dormancy genes in breeding varieties resistant to preharvest sprouting. A
phenotypic selection and recurrent backcrossing technique was used to introduce
dormancy genes from a wild-like weedy rice to a breeding line to determine their
effects and linkage with the other traits. Five generations of phenotypic
selection alone for low germination extremes simultaneously retained dormancy
alleles at five independent QTL, including qSD12 (R(2) > 50%), as determined by
genome-wide scanning for their main and/or epistatic effects in two BC(4)F(2)
populations. Four dormancy loci with moderate to small effects colocated with
QTL/genes for one to three of the associated traits. Multilocus response to the
selection suggests that these dormancy genes are cumulative in effect, as well
as networked by epistases, and that the network may have played a "sheltering"
role in maintaining intact adaptive haplotypes during the evolution of weeds.
Tight linkage may prevent the dormancy genes from being used in breeding
programs. The major effect of qSD12 makes it an ideal target for map-based
cloning and the best candidate for imparting resistance to preharvest sprouting.