A candidate gene approach identified phytoene synthase as the locus for mature fruit color in red pepper (Capsicum spp.)

The color of mature pepper fruit is determined by the composition of carote noids. The fruit color of red pepper is genetically determined by three loc i, y, cl, and c2. We have been developing agenetic map of hot pepper using RFLP and AFLP markers in the F-2 population of an interspecific cross betwe en Capsicum annuum cv TF68 and Capsicnm chinense cv Habanero. The color of the ripe fruit of TF68 is red and Habanero is orange. The red color is domi nant over orange in the F-1 and the locus controlling this character has be en marked in our SNU Linkage Group 7. To identify the gene or markers tight ly linked to the red/orange locus, several candidate genes involved in the carotenoid biosynthesis pathway, namely FPS, GGPS, PSY, PDS, LCY and CCS, w ere examined. One of the candidate genes, phytoene synthase, cosegregated c ompletely with furit color in the F-2 population. QTL analysis of the pigme nt content of F-2 individuals quantified by HPLC also indicated that phytoe ne synthase is the locus responsible for the development of fruit color. Th e color, pigment content and genetic behavior of Habanero also suggest that phytoene synthase may be responsible for the c2 gene discriminating betwee n red and orange cultivars.