In Vitro Embryo Culture studies in Papaya

Papaya (Carica papaya L.) being a delicious fruit has the problem of sex expression. On segregation, the gynodioecious cultivar segregates in the ratio of 1 (female); 2 (heterozygous andromonoecious): 1 (homozygous dominant andromonoecious) forms. The female is unproductive and due to post fertilization barrier, the embryo of homozygous dominant andromonoecious forms abort. Therefore, with the aim to produce high yielding gynodioecious lines of papaya, the aborting embryos are rescued at 50, 60 and 70 days after pollination and were induced to germinate and grow in the nutrient medium. Both the immature ovules and immature embryos were cultured in MS containing 6.0 mg/l BAP and 1.0 mg/l NAA. The immature embryos of age 50 DAP showed the highest germination of 95.00 and 87.50 percent with the longest shoot of 1.78 cm for SRS and 1.49 cm for CO 7. The embryo response for germination and growth were found to be the highest with sucrose at 8 g/l, coconut water 15 percent, casein hydrolysate 500 mg/l and L-glutamine 400 mg/l. The regenerated plantlets were hardened under controlled environmental condition.