We investigated inheritance and carried out gene fine mapping of aroma in crosses between the aromatic elite hybrid rice Oryza sativa indica variety Chuanxiang-29B (Ch-29B) and the non-aromatic rice O. sativa indica variety R2 and O. sativa japonica Lemont (Le). The F1 grains and leaves were non-aromatic while the F2 non-aroma to aroma segregation pattern was 3:1. The F3 segregation ratio was consistent with the expected 1:2:1 for a single recessive aroma gene in Ch-29B. Linkage analysis between simple sequence repeat (SSR) markers and the aroma locus for the aromatic F2 plants mapped the Ch-29B aroma gene to a chromosome 8 region flanked by SSR markers RM23120 at 0.52 cM and RM3459 at 1.23 cM, a replicate F2 population confirming these results. Three bacterial artificial chromosome (BAC) clones cover chromosome 8 markers RM23120 and RM3459. Our molecular mapping data from the two populations indicated that the aroma locus occurs in a 142.85 kb interval on BAC clones AP005301 or AP005537, implying that it might be the same gene reported by Bradbury et al (2005a; Plant Biotec J. 3:363-370). The flanking markers Aro7, RM23120 and RM3459 identified by us could greatly accelerate the efficiency and precision of aromatic rice breeding programs.
aroma; genetic analysis; gene fine mapping; rice (Oryza sativa L.)
