Effect of GA3 spraying on qualitative and quantitative characteristics of Citrus Reticulata cultivar Unsho

Background and objectives: Citrus is one of the most important fruit crops in the word because of the scale of its production and the health benefits derived from consumption of either fresh fruit or juice. Due to the disadvantages of the using pesticides for humans and the environment, new achievements in the use of compounds those adverse effects hasn’t on humans and the environment is very important. The use of natural compounds such gibberellins in commercial formulation could have been used in stages fruit rapid growth, per-harvest and post-harvest that result would be economical reactions. Therefore, this study was carried to aim evaluation effect of GA3 on the fruit qualitative and quantitative characteristics of Citrus Reticulata cultivar Unsho and attain to the best time for spraying.
Material and method: In order to evaluation effect of GA3 on the fruit qualitative and quantitative characteristics of Citrus Reticulata cultivar mid-season Unsho, this experiment was carried in a Completely Randomized Block Design (CRBD), with two factors GA3 in 5 levels and spraying time in 3 levels and with 3 replications in during years 20016 and 2017. GA3 levels including (0, 10, 30, 50 and 70 mg/l) and spraying time including (60, 45 and 30 days per-harvest). At the end of the experiment was evaluated morphological, fruit qualitative and quantitative characteristics and Mediterranean flies’ damage.
Result and discussion: The results showed that with GA3 spraying and increasing concentration its, in total of times studied, fruit weight, yield of per tree and yield of per hectare were increased significantly compare to the control. But the most rate of increase were observed in GA3 treatment (70 mg/lit) that were sprayed in 60 days of per-harvest. Also, fruits down fall percentage in per-harvest, Mediterranean flies’ damage percentage in total treatments were reduced significantly compare to the control. The results showed that GA3 treatment in concentrations (30, 50 and 70 mg/lit) were delayed fruits reaching time significantly compare to the control.
Conclusion: In total, GA3 treatment could have been increased fruits quantity and quality significantly to compare with the control. In between times studied, 60 days per-harvest was selected as the best time. However, with increasing concentration of GA3 to 70 mg/lit, Farmer gross income per product total sale and farmer gross income per yield increased ratio to control, were increased significantly to compare with the control. But the most of proportion total income to the per-unit cost and income obtained from yield increased ratio to per-unit cost concern using GA3, were observed in GA3 treatment to concentration 10 mg/lit that were sprayed in 60 days pre-harvest (219.43 and 22.49) respectively.