Dynamic changes in fruit growth and development of Actinidia ‘Jinyuan’ in two regions

To elucidate the growth and development of the Actinidia cultivar ‘Jinyuan’ and thus provide guidelines for the development of supported cultivation technology and determination of proper harvest time, fruit grown in the Danjiangkou (DJK) and Wuhan (WH) orchards were regularly measured and analyzed in regard to fruit weight, size, dry matter, soluble solids concentration (SSC), firmness, flesh color, soluble sugar, and total acidity. Results indicated that the size (vertical, horizontal, and lateral diameter) and weight of the fruit grown in both orchards showed a rapid-slow-cease growth trend, and the rapid growth stage mainly occurred within 57 d after full bloom (DAFB). Maturity indices, including dry matter, SSC, flesh color, and firmness, revealed strongly similar patterns during the whole growth period in both orchards, although dry matter was slightly lower and firmness was slightly higher in fruit from WH than from DJK. Dry matter increased to a primary plateau at 135 DAFB. Both SSC and soluble sugar began to increase rapidly from 127 DAFB and reached 8% and 3.5%, respectively, at 148 DAFB. Both fruit firmness and flesh color gradually declined with growth time, with firmness beginning to decline largely at 168 DAFB and flesh color decreasing to 103° hue at 155 DAFB. Taken together, ‘Jinyuan’ fruit should be properly harvested at 150–155 DAFB.