FAN Fang-jun;FAN Ye-yang;Du Jing-hong;ZHUANG Jie-yun

Chinese National Center for Rice Improvement/State Key Laboratory of Rice Biology; China National Rice Research Institute; China; Hangzhou 310006

C locus;fine mapping;candidate gene;residual heterozygous line;rice

Seven residual heterozygous lines (RHLs) displaying different genotypic compositions in the genomic region covering probable locations of C (Chromogen for anthocyanin) gene on the short arm of rice chromosome 6 were selected from the progenies of theindica cross Zhenshan 97B/Milyang 46. Seeds were harvested from each of the seven plants, and the resultant F_(2:3) populations were used for fine mapping of C gene. It was shown in the populations that the apiculus coloration matched to basal leaf sheath coloration in each plant. By relating the coloration performances of the populations with the genotypic compositions of the RHLs, the C locus was located between rice SSR markers RM314 and RM253. By using a total of 1279 F_(2:3) individuals from two populations showing coloration segregation, the C locus was then located between RM111 and RM253, with genetic distances of 0.7 cM to RM111 and 0.4 cM to RM253. Twenty-two recombinants found in the two populations were assayed with seven more markers located between RM111 and RM253, including six SSR markers and one marker for the C gene candidate, OsC1. The C locus was delimited to a 59.3-kb region in which OsC1 was located.