Effects of Growth Regulators Ethephon and 2,4-D Isopropyl Ester on Fruit Ripening and Quality of Fig under Rain-Fed Conditions.

Fig (Ficus carica L. cv. Sabz) fruit growth and development under rain-fed conditions differs from fig grown under irrigated conditions and responds differently to the growth regulators application. This study aimed to reveal how ethephon (0, 50, 100, 150, 200 mg L-1) and 2,4-D isopropyl ester (0, 5, 10, 15, 20 mg L-1) can accelerate fruit ripening in fig cv. 'Sabz'. Fruits were sprayed three times by foliar application at 15-days intervals for two consecutive years. The highest fruit ripening percentage occurred with the second time that ethephon (200 mg L-1) was sprayed. Application of 100 mg L-1 ethephon increased the total soluble solids with the second and third foliar spraying. Ostiole cracking in dry fig fruits became most prevalent when applying 50 mg L-1 ethephon by the third foliar spraying. The highest carotenoid content was caused by 100 mg L-1 ethephon by the second foliar application. Furthermore, the highest sugar content occurred in response to the second foliar spraying of 50 mg L-1 ethephon. The second 2,4-D isopropyl ester (10 mg L-1) foliar spraying significantly increased fruit diameter. Since the crop has asynchronous nature of ripening, harvesting continued for several weeks. Ethephon (200 mg L-1) accelerated fig harvesting and made it occur about 7 days sooner under rain-fed conditions. Therefore, accelerating fig fruits ripening can reduce the likelihood that fruits will be exposed to drought near the end of the season. Also, ethephon treatment can help prevent loss of fruit quality. [ABSTRACT FROM AUTHOR]