while size reached a maximum at 20 days after
flowering (DAF), fruit weight continued to increase gradually. The respiration rate of fruit
left attached to the vine until just before measurement decreased gradually with time but
without showing a climacteric peak; ethylene production increased sharply soon after 70
DAF, thereafter remaining constant. After successive detachment of fruit at or after 40
DAF, a respiratory peak was shown, the onset of which occurred quicker the longer the
fruit had remained attached. The onset of the rise in ethylene also depended on the length
of attachment and then increased rapidly. As fruit matured, soluble solids conte,nt steadily
increased and reached maximum levels at 70 DAF while titratable acidity increased rapidly
up to 60 DAF and then decreased up to 80 DAF. Changes in fruit color from green to purple
was attained between 70 and 80 DAF and this corresponded with the commencement of
autocatalytic ethylene production. The results indicate that purple passion fruit appear to
attain physiological maturity at about 60 DAF and can be harvested with acceptable quality
at about 70 DAF for commercial use.