Sex Type Identification in Papaya (Carica papaya L.) by Random Amplified Polymorphic DNA

Abstract

Papaya is a polygamous diploid (2n=18) trioecious plant which possesses three sex types: female, male and hermaphrodite. Hermaphrodite plants are popular worldwide for their long fruit shape, high percentage of edible parts, and easy-package. Therefore, papaya sex discrimination at nursery stage is critical economy issue for growers to consider; however, phenotype discrimination is difficult, low efficiency, and easy-affected by external environment condition. Random amplified polymorphic DNA (RAPD) was used in this study to examine the sex type of papaya Tainong No.2. After screening of 80 random primers, sixteen primers showed polymorphisms between different sex types of papaya were obtained. Among them, primer OPC05 (GATGACCGCC) amplified a 1682 bp fragment from both male and hermaphrodite can be used to discriminate the sex type of papaya plants at seedling stage. After compared with other DNA sequences from NCBI (1998) databases, the 1682 bp DNA sequence was supposed belonging to papaya Y chromosome.