The impact of the training system on the yield potential of the “Čačanska Rana” cultivar in the second and the third years after planting

Abstract

The “Čačanska Rana” is a table plum cultivar, with early ripening season and with a vigorous to very vigorous tree, when grafted onto Prunus cerasifera, Ehrh. It is a known fact that more radical wintertime pruning in initial years will contribute to the vigour effect and postpone fruit-yielding when conventional training systems such as the ‘improved pyramid’ or the ‘vase’ are used.

The paper presents the results on the presence of various types of fruit-bearing branches in the second and the third years after planting, with the ‘Čačanska Rana’ cultivar grafted on the wild plum (Prunus cerasifera, Ehrh.) and cultivated in two different training systems:
1. ‘the spindle bush’, with 1250 trees per hectare, and without the wintertime pruning in the initial years after planting, and with the application of adequate operations during the summertime pruning, and
2. ‘the vase’, with 400 trees per hectare, with the wintertime pruning as the only operation used in establishing the training system used.

The results were that with the ‘spindle bush’ training system, the initial yield potential was achieved as early as in the second year after planting (there were 0.40 mixed and 0.80 short flowering, fruit-bearing branches per tree). However, the variation coefficient was rather high (Cv = 50.83%), meaning that the yield potential significantly varied between the trees. With the cultivar grown in the ‘vase’ training system and without summertime pruning in the first growing season, no yield potential whatsoever was recorded in the second year after planting.

During the third year after planting, the ‘Čačanska Rana’ trained to the “spindle bush” system showed a significant yield potential. It had 0.95 mixed-type, 22.25 short flowering fruitbearing branches, and 3.85 May blossoms per tree. The variation coefficient was significantly reduced, when compared to the second year, amounting to 12.28%. The same cultivar with the “vase”-trained tree and with standard wintertime pruning used, recorded the following initial yield potential in the third year after planting: 1.90 mixed and 1.35 short flowering fruit-bearing branches per tree (Cv = 19.80%).