Efectul regulatorilor de creștere asupra normării organelor reproductive, productivității și calității fructelor la soiul de măr Golden Delicious

Proper management of the crop load is necessary to achieve an appropriate balance between the yield and the fruit size. The study was conducted in the period 2016-2018 with the purpose to assess the effect of various crop load management practices on the Golden Delicious apple variety, grafted on the rootstock M9, in an intensive system. The trees aged 8-10 years were trained according to improved slender spindle shape and planted at a distance of 3.5 x 1 m. Experimental design: a) control, untreated trees; b) fruit manual thinning performed after the physi­ological drop, when the fruits reached a diameter of 16-18 mm; c) chemical thinning with the preparations: 1) Urea solution 46% N, 6 kg/ha, at a temperature of 12-25oC and air humidity of 65-80%, when 75% of the flowers are open until the petals of the first flowers dropped; 2) Geramid New solution, 1.5 l/ha, at a temperature of 15-20 oC, when the central fruit reached a diameter of 4-7 mm; 3) LG Dira Max solution, 2,l/ha at a temperature of 18-25oC, when the central fruit reached a diameter of 10-15 mm. The experiment was organized in 4 repetitions, the spraying was per­formed on 8 trees in each repetition, using 11 l of solution on 32 trees or 1000 l per hectare, respectively. The authors calculated the number of red dotted buds, the number of inflorescences that set fruit, the average number of fruits per tree as well as the average weight and diameter of fruits. The used growth regulators ensured a significant increase in the average weight of a fruit (135,4-144,4 g) and a significant increase in the diameter of fruits (over 85% of fruits have been classified in the category I and Extra category), but significantly reduced the number of fruits per tree.