PCR detection assay for sex determination in papaya using SCAR marker

Abstract

Papaya (Carica papaya L., 2n = 18), a polygamous angiosperm, is a major fruit crop in tropical and subtropical regions. It is trioecious with three sex forms: male, female, and hermaphrodite, where sex determination is controlled by the XY chromosome pair with two slightly different Y chromosomes i.e. Y for male and Yh for hermaphrodite. Sex type determination in papaya, which cannot be determined either by embryo shape or morphology at the juvenile developmental stage, is an essential pre-requisite for crop improvement processes as it helps in identification of fruitful plants. Hence, molecular profiling could be used as an alternative that provides a quick and reliable identification of sex types in plantlets at initial stages only. In the present study we have validated the sexlinked sequence characterized amplified region (SCAR) marker W11 using PCR detection assay among different cultivars of papaya i.e. dioecious with either female or male and gynodioecious with either female or hermaphrodites and also performed a double-blind test for validating the seedlings of 84 F1 plants, which resulted in their sex determination. The assay clearly gives 800 bp band in male plants in dioecious types and hermaphrodite in gynodioecious plants.