Reference "Fine linkage mapping enables dissection of closely linked quantitative trait loci for seed dormancy and heading in rice"

Reference ID

8183

Title

Fine linkage mapping enables dissection of closely linked quantitative trait loci for seed dormancy and heading in rice

Source

Theoretical and applied genetics, 2003, vol. 107, pp. 1174-1180

Authors (4)

Takeuchi-Y	Lin-S-Y
Sasaki-T	Yano-M

Abstract

Two quantitative trait loci (QTLs) for seed dormancy (tentatively designated
Sdr1) and heading date ( Hd8) have been mapped to approximately the same region
on chromosome 3 by interval mapping of backcross inbred lines derived from
crosses between the rice cultivars Nipponbare (japonica) and Kasalath (indica).
To clarify whether Sdr1 and Hd8 could be dissected genetically, we carried out
fine-scale mapping with an advanced backcross progeny. We selected a BC(4)F(1)
plant, in which a small chromosomal region including Sdr1 and Hd8, on the short
arm of chromosome 3, remained heterozygous, whereas all the other chromosomal
regions were homozygous for Nipponbare. Days-to-heading and seed germination
rate in the BC(4)F(2) plants showed continuous variation. Ten BC(4)F(2) plants
with recombination in the vicinity of Sdr1 and Hd8 were selected on the basis of
the genotypes of the restriction fragment length polymorphism (RFLP) markers
flanking both QTLs. Genotypes of those plants for Sdr1 and Hd8 were determined
by advanced progeny testing of BC(4)F(4) families. Sdr1 was mapped between the
RFLP markers R10942 and C2045, and co-segregated with C1488. Hd8 was also mapped
between C12534S and R10942. Six recombination events were detected between Sdr1
and Hd8. These results clearly demonstrate that Sdr1 and Hd8 were tightly
linked. Nearly isogenic lines for Sdr1 and Hd8 were selected by marker-assisted
selection.