Efficacy of gene-based markers associated with sex expression in papaya

Abstract

The papaya (Carica papaya L.) is a polygamous plant, has three types of sex forms, viz. male, female and
hermaphrodite. Efforts were made to identify sex expression and validation of gene-linked molecular markers
associated with it. Molecular markers (ISSR and SCAR) were employed to distinguish male, female and
hermaphrodite sex forms in seedlings and well differentiated adult plant types. The important markers which have
been found linked with sex forms in papaya were used for validation in population of six papaya genotypes. Total
10 sex linked DNA markers (9 SCAR and 1 ISSR) were employed for validation of sexes in 6 papaya genotypes
(dioceious and gynodioecious) . Out of 10 only five (T12, W11, SCAR SDSP, C09/20 and GACA4) were amplified
for the sex expression. However, five SCAR (SCARp, SCARpm, T1, STS 807 and STS 831) marker did not get
amplified with the all sex genotypes. Of the two marker systems tested, SCAR markers were most consistent.
Markers, namely, T12, CFW+CRV and W11 were most informative to predict cent per cent sex forms. These
markers can be used by the breeders and commercial papaya growers to identify desired sex types at seedling
stage in nursery for establishing a productive plantation.