Abstract:

A restoring line N91 with late heading period (from 110 d to 114 d) was found from the offspring of a cross (Jinhui 10/R21), and N91 was crossed and backcrossed with Jin 23A, which was sterile line with early heading period (89–94 d). The frequency distribution of heading period showed double peaks in F2 and BC₁F₁ population and χ square test demonstrated the heading period was controlled by a major gene, which tentatively named as Hd(t), and other minor genes. Bulkled segregant analysis was used to map the Hd(t) by the backcross population, and 5 out of 400 SSR primer pairs showed polymorphism between late and early genome pools. Linkage analysis demonstrated the Hd(t) linked with two SSR loci (RM1364, RM3555) on chromosome 7. The Hd(t) were 32.7 and 22.5 cM from loci RM1364 and RM3555 respectively, and two SSR loci located at the same side of the Hd(t). Based on the targeted interval, 8 pairs of primers were selected from the public SSR primer pairs according to rice physical map. Through linkage analysis, RM22143 was added into the interval of the RM3555 and Hd(t) on the distal end of long arm of chromosome 7, and Hd(t) was 12.9 cM from RM22143. The present result establishes a basic for fine mapping, molecular marker assisted breeding and gene cloning of the Hd(t).

Key words: Rice, Heading period, Genetic analysis, Gene mapping, SSR marker