Genetic analysis and gene fine mapping of aroma in rice (Oryza sativa L. Cyperales, Poaceae)

Abstract

Abstract Weinvestigatedinheritanceandcarriedoutgenefinemappingofaromaincrossesbetweenthearomaticelitehybridrice Oryza sativa indicavariety Chuanxiang-29B (Ch-29B) and the non-aromatic rice O. sativa indicavariety R2 andO. sativa japonicaLemont (Le). The F 1 grains and leaves were non-aromatic while the F 2 non-aroma to aroma segre-gation pattern was 3:1. The F 3 segregation ratio was consistent with the expected 1:2:1 for a single recessive aromagene in Ch-29B. Linkage analysis between simple sequence repeat (SSR) markers and the aroma locus for the aro-matic F 2 plants mapped the Ch-29B aroma gene to a chromosome 8 region flanked by SSR markers RM23120 at0.52 cM and RM3459 at 1.23 cM, a replicate F 2 population confirming these results. Three bacterial artificial chromo-some(BAC)clonescoverchromosome8markersRM23120andRM3459.Ourmolecularmappingdatafromthetwopopulations 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 flankingmarkers Aro7, RM23120 and RM3459 identified by us could greatly accelerate the efficiency and precision of aro-matic rice breeding programs.