Morphological and biochemical methods for sex determination in papaya (Carica papaya) seedlings

Abstract

A single female papaya plant normally produces as many as 100 fruits in its life cycle and about 250 gm of crude papain a year. Thus, an increase in the number of fruit bearing trees per hectare of land would directly increase in the yield of fruits and papain, making the cultivation more profitable. A field study was carried out at Crop Physiology Unit, Department of Agronomy, Agricultural College & Research Institute, Killikulam, Vallanad, Tuticorin district of Tamil Nadu. Two varieties of papaya differing in their sex behaviour viz., CO 8 a dioecious variety and Red lady, a hermaphrodite variety were selected. The seed physiological characters such as germination percentage, pH and EC of seed leachate were studied. The biochemical constituents of the papaya leaves such as protein, phenol and IAA oxidase activity were estimated. It was found that a highly significant positive correlation was found to exist between 100 seed weight and male sex, but a negative correlation with females and hermaphrodite. The IAA oxidase activity was considered as one of the aids for sex differentiation.