Effects of NAA and GA3 Sprays on Yield, Fruit Size, Fruit Splitting and the Incidence of Creasing of Nova Mandarin
(0) Nova mandarin in Israel suffers from fruit splitting,which causes fruit abscission and losses of up to 50％ of the yield,and creasing. In over-cropping Nova orchards fruit thinning is also required for increasing fruit size and alternate bearing reduction. Effects of the auxin naphthaleneacetic acid (NAA, 300mg/L) and gibberellic acid (GA3,20mg/L) on yield,fruit size,fruit quality,fruit splitting and the incidence of creasing were studied. NAA spray solutions were tank-mixed with Bonus-NPK fertilizer (5％ ). NAA sprays were applied to whole trees on two dates: 1) June,at 20mm fruitlet diameter and 2) July,at 28mm fruitlet diameter. GA3 sprays were applied at 28mm fruitlet diameter and at 37mm fruitlet diameter. The June NAA treatment thinned 34％ of the fruit, but since the size of the remaining fruit was increased,this treatment only reduced yield by 9％. The July NAA treatment and the GA3 treatments did not thin fruit and had no effect on fruit size. Most fruit splitting occurred between the beginning of October and the beginning of November,and the total fruit splitting in the untreated control trees was 227 fruit/tree. The June NAA and July NAA treatments reduced fruit splitting to 114 and 108 fruit/tree,respectively. The GA3 treatments had no effect on fruit splitting. The percentage of severe creasing in the control trees was 38％. The NAA treatments,at both application dates,reduced the incidence of severe creasing to 7％. The GA3 treatments at 28mm and 37mm fruit diameter reduced the incidence of severe creasing to 5％ and 11％. respectively. The treatment of tank-mixed solution of NAA + GA3,applied when fruitlets were 28mm in diameter,reduced the incidence of severe creasing to only 2％. The plant growth regulators (PGRs) had no significant effects on the percent of juice, total soluble solids and acid content of the fruit. These data suggest that late applications of NAA on large fruitlets,at the stage that fruit size and fruit thinning are not affected, is effective for reducing fruit splitting and the incidence of creasing of Nova mandarin. When fruit thinning and enlarging fruit size is also desired,NAA should be applied on smaller fruitlets.
Citrus Auxin Fruit thinning 3,5,6-TPA Fruit quality
J. Greenberg I. Kaplan M. Fainzack Y. Egozi B. Giladi
Ministry of Agriculture, Extension Service, P. 0. Box 28, Bet Dagan 50250, Israel Mehadrin-Prior, Power center 1 ,Beerot Yizhak 60905, Israel
国际会议
11th International Citrus Congress(第11届国际柑橘大会)
武汉
英文
538-541
2008-10-01（万方平台首次上网日期，不代表论文的发表时间）