Ethephon as a potential tool to manage alternate bearing of ‘Fuji’ apple trees

ABSTRACT The objective of this study was to investigate the effect of different rates of ethephon on return bloom and yield, and fruit quality of ‘Fuji’ apple trees. The experiment was performed during the 2014/2015 and 2015/2016 growing seasons. Eighteen-year-old Fuji Standard apple trees grafted on M.9 were sprayed with different rates of ethephon (300 mg L-1, 400 mg L-1, and 500 mg L-1) 30 days after full bloom (DAFB) and compared to an unsprayed control. Yield components (number of fruit per tree, yield, fruit weight, and estimated yield) and fruit quality attributes (fruit firmness, total soluble solids and starch-iodine index) were evaluated in both seasons. Return bloom (percentage of flowering spurs and 1-year-shoots) was assessed only the year following the application. Our results show that ethephon increases return bloom and yield of ‘Fuji Standard’ apple trees, without affecting fruit quality attributes.摘要 本研究旨在探究不同浓度乙烯利（ethephon）对‘富士’标准苹果树返花、产量及果实品质的影响。试验于2014/2015与2015/2016两个生长季开展，以嫁接于M.9砧木的18年生富士标准苹果树为试材，于盛花后30天（Days After Full Bloom, DAFB）喷施300 mg·L⁻¹、400 mg·L⁻¹及500 mg·L⁻¹三种浓度的乙烯利，并设置未喷施的对照组。两个生长季均测定了产量构成因子（单株结果数、产量、单果重及预估产量）与果实品质指标（果实硬度、可溶性固形物总量及淀粉-碘指数）；返花情况（结果短枝与一年生枝的开花百分比）仅在施药次年进行评估。研究结果表明，乙烯利可提升‘富士’标准苹果树的返花率与产量，且对果实品质指标无不良影响。