Effects Of Exogenous Gibberellin Acid On The Quality Of Different Mango Cultivars

The effects of spraying GA₃ with different concentrations of GA₃ on the storage quality and appearance quality of mango fruits were studied by using the experimental materials of mango cultivars "Tainong 1" and "Hong Guifei" in Hainan Province, including their dynamic changes in color and post-harvest physiological effects. The results were as follows:The different concentrations of GA₃ on the effects of "Tainong 1" mango was different. The lower concentration of GA₃ could delay the degradation rate of chlorophyll and inhibit the synthesis of carotenoid and anthocyanin. It can decreased the variations of fruit TSS content, decrease VC loss, maintain fruit firmness, and delay the ripening and senescence. The results showed that the effect of 2.0 g/L treatment concentration to"Tainong 1" was the best.The decay index, convert yellow ratio, the color a* value, carotenoid content,anthocyanin content, chlorophyllase activity, PAL activity and chalcone activity gradually increased during fruits storage before spraying with different concentrations of GA₃ ?0.0,0.3,0.5,1.0,2.0 and 3.0 g/L? to "Honggui Fei" mango fruits. Meanwhile, the chlorophyll content decreased gradually, and the mango peel changed from green to red and yellow to reddish yellow. The effects of GA₃ treatment on mango fruit color and physiology were different. Too high or too low concerntration of GA₃ treatments was not conducive to mango rot disease inhibition. The results showed that mango fruit rot disease inhibition under 1.0g / L GA₃ treatment was the best. GA₃ treatment before harvest could inhibit the yellowing of mango fruit, the higher the concentration, the more obvious the delaying trend.The GA₃ postharvest treatment of "Hong Guifei" mango fruits could reduce the contents of VC and TSS in fruit of mango fruit, and maintained higher TA content and hardness, retarded the degradation of chlorophyll, delayed the synthesis of anthocyanin and carotenoid, delayed the synthesis of mango peel color change, slowed down the increase in the index to yellow, and inhibited the occurrence of disease. However, GA₃ treatments under the concentration of 3.0 and 4.0 g/L could make "Hong Guifei" mangoes not completely turn color at the end of storage period, with relatively high chlorophyll content,and relatively low carotenoid content and anthocyanin content, then affected the taste and after-ripening color of mango, thus affected the mango storage quality and commercial value. Therefore, we suggested the production of "Hong Guifei" mango treatment GA₃ concentration control in the 2.0 g/L within the appropriate.In conclusion, GA₃ treatment with different concentrations had significant effects on appearance color, storage quality and postharvest physiology of two varieties of mango fruits. For the "Tainong l" mango, 2.0 g/L GA₃ immersion treatment could maintain the appearance quality and delay the maturation and senescence. For the "Hong Guifei" mango,1.0 g/L GA₃ spraying treatment before harvest, and 2.0 g/L GA₃ postharvest treatment had the best inhibitory effect on fruit rot, and it could maintain good nutritional quality,appearance quality and high commercial value. The results could provide reference for mango preservation industry.