Effects of Prohexadione-Ca, Ethephon, and Water Stress on Growth and Productivity of 'Golden Delicious'/M.9 Apple

Abstract

Abstract. Prohexadione-calcium (Pro-Ca), ethephon and transient water stress were evaluated in a factorial design, as potential inhibitors of early-season shoot growth of high density orchard management of apple (Malus domestica Borkh.) trees. In the experiment, water stress was imposed to one-half of the 7-year-old 'Golden Delicious'/M.9 apple trees in each of 5 blocks, by stopping irrigation for 3 weeks between 35 and 56 days after full bloom (AFB). Within each whole unit, the following Pro-Ca and ethephon treatments were randomly allocated at 2 × 2 factorial: a) 0 or 250 mg･L -1 a.i. Pro-Ca applied at 28 days AFB and b) 0 or 300 mg･L -1 a.i. ethephon applied twice (35 and 71 days AFB). All trees were hand thinned to king flowers prior to treatments. Vegetative shoot growth was markedly reduced by Pro-Ca, with its effect being obvious within 14 days after application, while ethephon and water stress treatments were less effective. Pro-Ca had no effect on fruit set and yield but slightly increased fruit size. Ethephon substantially reduced the fruit size and yield but had no effect on fruit set. Water stress reduced fruit set, fruit size and yield. With regard to fruit quality, Pro-Ca did not influence fruit shape, flesh firmness and soluble solids contents (SSC) but slightly reduced titratable acidity. Ethephon had no effect on fruit shape but increased firmness, SSC and acidity, while water stress did not influence these fruit quality attributes. Dry weight of dormant spur buds was reduced by both Pro-Ca and water stress, while increased by ethephon. The larger dormant buds led to the larger spur flowers at the tight cluster stage the following spring. Return flowering was promoted only by ethephon, especially on previous season's shoots. There were no significant interactions between Pro-Ca and ethephon or water stress on most variables observed in this study.Additional key words: fruit quality, fruit set, gibberellin biosynthesis inhibitor, return bloom, specific leaf weight, stomatal conductance, water potential

Prohexadione calcium on the growth and quality of eggplant seedlings

“…All prohexadione calcium concentrations significantly reduced internode length in comparison to the control. These results are in agreement with previous studies conducted with other vegetable and fruit crops (Rayirath et al, 2009;Kim et al, 2010;Guak, 2013). Soaking of faba bean (Vicia faba L.) seeds in solutions of prohexadione calcium caused significant reduction in shoot height and fresh weight, with increasing prohexadione calcium concentrations (Bekheta et al, 2009) There were no significant differences in stem diameter and number of true leaves between the prohexadione calcium treatments and the control plants (Table 1).…”

Influence of prohexadione-calcium and paclobutrazol on growth, yield and mineral content of pear cv. Clapp’s favourite

“…However, minimum potassium (10.12 mg) in fruits was recorded in control (T 1 S 0 ). Our results are in conformity with Guak et al (2013) [8] in apple cv. 'Golden Delicious'.…”

Influence of prohexadione-calcium on temperate fruit crops – A Review

“…Highest fruit width (80.71 and 79.34 mm), fruit length (72.04 mm in the second year) and fruit weight (222.68 g in the second year) were observed with 250 g/100 l pro-ca dose in Starcrimson delicious apple plants (Çetinbas et al, 2015). In a study, conducted by Guak (2013) on the apple cv. Golden delicious to determine the efficacy of prohexadione-calcium, ethephon both at 250 mg/ l and transient water, resulted in good higher fruit weight.…”