VARIETAL IMPROVEMENT OF PAPAYA (CARICA PAPAYA L.) FOR FRESH CONSUMPTION

Varietal improvement of papaya comprised three sub-projects, varietal improvement of 'Khaek Dam', varietal improvement of 'Khaek Nuan' and an evaluation of F₁ hybrid varieties. The objectives were to improve fruit quality of 'Khaek Dam', to improve fruit quality the 'Khaek Nuan' and to evaluate fruit quality of the F₁ hybrid varieties. For varietal improvement of 'Khaek Dam', 16 selected clones of 'Khaek Dam' were used for evaluation. Fresh and fully mature fruits with 5-10% ripeness were harvested at approximately 8 months after planting. Four clones showed a high number of fruits per plant of 20-35 fruits and also fruit fresh weight of 30-80 kg. Color of flesh was reddish-yellow and flesh firmness ranged from 0.7-0.8 kg cm^-1 with TSS of 9-11°Brix. Fruits were recommended for fresh consumption, both green and ripe fruits and also for processing. For varietal improvement of 'Khaek Nuan' variety, 65 clones of 'Khaek Nuan', derived from Chantaburi and Sisaket were used for selection. Five clones had 25-40 fruits and fruit weight of 50-60 kg per tree. Color of flesh was reddish-yellow and flesh firmness was aproximately 0.7 kg cm^-1 with TSS of 10-11°Brix. Fruits were recommended for fresh consumption, both green and ripe fruits and for processing. For evaluation of hybrid papaya varieties, eleven hybrid lines were used. Five hybrid lines showed prominent fruit quality having a high number of fruits per plant and fruit fresh weight of 30-40 fruits and 50-70 kg, respectively. Color of flesh was reddish-yellow and fruit firmness was approximately 0.6-0.7 kg cm^-1 and TSS of 9-10°Brix. Fruits were recommended for both green and ripe eating.