Molecular genetics of the y locus in pepper: Its relation to capsanthin- capsorubin synthase and to fruit color

Classical genetic studies have determined that the yellow fruit color in pepper is recessive to red in the locus y. We studied the relation of the y locus with the gene coding for capsanthin-capsorubin synthase (CCS) that synthesizes the red carotenoid pigments in the mature fruit. Cosegregation of y and CCS in populations derived from crosses between plants beating redxwhite and redxyellow fruits indicated the correspondence of the two genes. We obtained indications for the occurrence of a deletion in the CCS gene in plants containing the recessive y allele. This deletion did not contain the distal 220 bp of the 3' end of the gene. We used the CCS gene to determine the genotype of peppers with different fruit colors at the y locus. In BC₁ segregants from a redxwhite cross, the red and peach-fruited progenies had the wild-type allele at the CCS locus, while the orange, yellow and white-fruited progenies had the mutant allele. Screening orange-fruited cultivars with CCS as well as segregation analysis of CCS in an additional redxwhite cross indicated two possible genotypes of the orange fruit color in this locus.