Trends of carbohydrate changes and the effect of NAA on yield and alternate ‎bearing of Miyagawa Satsuma mandarin‏ ‏‎(Citrus unshiu cv. Miyagawa)‎

In order to investigate the state of carbohydrates and the effect of naphthalene acetic acid (NAA) application on yield and alternate bearing of Miyagawa Satsuma mandarin, two separate experiments were performed an Miyagawa Satsuma mandarin oechard. In the first experiment, the trend of changes in the concentration of carbohydrates (soluble sugars and starches) in the leaves and roots of trees were investigated. The second experiment were performed as randomized complete blocks design with 4 replications during 7 years. Treatments included: control; 150, 300 and 450 mg/l NAA spraying before physiological abscission of fruitlets. The results of the first experiment showed that the average changes of starch and soluble sugars in foliar leaves and roots were about 6.3 times and 2.34 times higher, respectively. The results of the second experiment showed that NAA application in the first stage of fruit growth in “on” years, increased yield in “off” years, and gradually yield variation in “on” and “off” years decreased. So that treatment 300 mg NAA l-1 had the highest cumulative yield and the lowest alternate bearing index. However, all NAA treatments reduced alternate bearing index compare to control, significantly. Therefore, based on the results of this project to modulate alternate bearing, spray NAA in “on” at a concentration of 300 milligrams per liter from 25 days after flowering to about 40 days after flowering is recommended.