Growth and development of winter fruit of Jindubaixiang No. 3 passion fruit and its quality formation pattern

【Objective】This paper studied the growth，development and quality formation pattern of the winter fruit of Jindubaixiang No.3（JD3）passion fruit，so as to provide scientific guidance for fruit nutrition regulation and picking time selection.【Method】By observing and measuring the longitudinal diameter，transverse diameter，single fruit weight，peel weight，peel thickness，soluble solid content，titratable acid content，reducing sugar content and vitamin C content of JD3 winter fruit during each period of development，this paper studied the change rules of quality-related indicators and key period of quality formation；further analyzed and clarified the correlation between the dynamic changes of fruit quality and evaluated the quality of winter fruits.【Result】The juice formation of JD3 winter fruit began at 45 d after flowering. The juice discoloration began at 50 d after flowering. The peel discoloration began at 90 d after flowering. The fruit was ripe and shed naturally at 130 d after flowering. The fruit longitudinal diameter，transverse diameter，edible rate and juice rate of JD3 showed a trend of slow growth，then rapid growth，and finally gradually levelling off，and reached the maximum at 25，30，110 and 110 d after flowering respectively and remained stable. The single fruit weight reached the maximum at 95 d after flowering. The weight and thickness of peel began to decrease at 35 d after flowering and tended to be stable at 110 d after flowering. Total soluble solid content and the ratio of total soluble solid content to titratable acid content showed a rising trend in general，and reached the maximum at full ripening. The contents of titratable acid，reducing sugar and vitamin C increased at first and then decreased，reaching the maximum at 80，120 and 110 d after flowering respectively. The dynamic changes of content of titratable acid were negatively correlated with the contents of reducing sugar， total soluble solid and vitamin C during JD3 winter fruit development.【Conclusion】The key period for the appearance quality formation of JD3 winter fruit is 0-30 d after flowering and 90 d after flowering to full ripening of fruits. The key period for the internal comprehensive quality formation is 90-120 d after flowering. And 110 d after flowering is the best time for the comprehensive quality performance of JD3 winter fruits.