Mechanical Thinning Improves the Consistency of Flowering and Yield in Apple Production

Abstract

Abstract Most apple cultivars tend to bear biennially, i.e. produce many fruits in one and few fruits in the next year, or do not have a nature of self-thinning. The effectiveness of chemical thinning depends on conditions, particularly temperature, at the time of application. In some other fruit-growing regions, the mechanical thinning of flowers is adapted to some cultivars by changing the speed of moving and rotation of the mechanisms to conduct partial thinning — removing of flowers. The investigation aimed to evaluate the effectiveness of total flower removal mechanically on one side of the tree row, and on the other side the next year, during the full production period (8th to 12th year after planting) to obtain regular yields. Seven cultivars on dwarfing rootstocks M.9 and B.396 were compared. Apple trees on the dwarfing rootstock B.396 were less affected by biennial yielding. Cultivars had a strong relation to yield — ‘Gita’ (Vf), ‘Konfetnoye’ and ‘Kovalenkovskoye’ had less fluctuation yearly, while ‘White Transparent’, ‘Rubin’ (Kazah.), ‘Antei’, and ‘Ligol’ performed opposite. There was a positive influence observed on reduction of periodicity by mechanical flower thinning, however, there is a discussion on cumulative yield reduction.