Reference "Genetic analysis of adaptive syndromes interrelated with seed dormancy in weedy rice (Oryza sativa)"

Reference ID

9521

Title

Genetic analysis of adaptive syndromes interrelated with seed dormancy in weedy rice (Oryza sativa)

Source

Theor Appl Genet, 2005, vol. 110, pp. 1108-1118

Authors (5)

Gu-X-Y	Kianian-S-F
Hareland-G-A	Hoffer-B-L
Foley-M-E

Abstract

Seed dormancy in rice interrelates to the weedy characteristics shattering, awn,
black hull color, and red pericarp color. A cross between the weedy strain SS18-
2 and the breeding line EM93-1 was developed to investigate the genetic basis
and adaptive significance of these interrelationships. These characteristics or
their components differed in average degree of dominance from -0.8 to 1.5, in
heritability from 0.5 to 0.96, and in their contribution to phenotypic or
genotypic variation in dormancy by up to 25%. Five dormancy, four shattering,
and three awn-length quantitative trait loci (QTLs) were detected in the BC1
population replicated in 2 years. Two QTLs for hull color were identified, and
the SS18-2-derived and EM93-1-derived alleles increased the intensity of black,
and red or yellow pigmentations, respectively. The only QTL for pericarp color
co-located with the red pericarp gene Rc, with the SS18-2-derived allele
increasing the intensity of black and red pigmentations. Four of the five
dormancy QTLs were flanked or bracketed by one to four QTLs for the interrelated
characteristics. The QTL organization pattern indicates the central role of seed
dormancy in adaptive syndromes for non-domesticated plants, implies that the
elimination of dormancy from cultivars could arise from the selections against
multiple interrelated characteristics, and challenges the use of dormancy genes
at these loci in breeding varieties for resistance to pre-harvest sprouting
(PHS). However, another QTL (qSD12) provides candidate gene(s) for PHS
resistance because it has a large effect in the population and it is independent
of the loci for interrelated characteristics.