Determination of a sex-related RAPD marker in Carob (Ceratonia siliqua L.)

Molecular markers are used in the characterization and breeding of organisms. Carob (Ceratonia siliqua L.) is a species with both dioecious and hermaphrodite flower forms. The determination of sex at an early stage of growth in this species, whose juvenility period is long, is important in breeding studies. The objective of this study was to identify the sex-related markers using RAPD method. Ten genotypes were obtained from natural F1 hybrids between a naturally grown a female and a male carob tree. DNA was extracted from the leaves of 12 carob plants. Using BSA, the female and male bulks were formed from five female and five male plants, respectively, using equal amounts of DNA from each plant. In this study, 130 RAPD primers were tested. That of 21 primers tested showed polymorphisms between male and female bulks. While the fragment of 750 bp from the OPA17 RAPD primer was not detected in the female parent, female bulk, and female F1 hybrids; it was observed in the male parent and four out of five male F1 hybrids. This is the first report in the literature that one RAPD marker, namely OPA17-750, related to 80% reliability to male sex in carob was determined.