Morphological characteristics of fruiting twigs in plum cultivars (Prunus domestica L)

Abstract

In order to achieve high yields and high-quality fruits in modern commercial plum production, it is necessary to rely on the application of agri - and pomo-technical measures, among which pruning holds the most prominent place. To know how to prune properly, one should know the characteristics of a cultivar's fruiting twigs. Morphological characteristics of fruiting twigs were studied in 20 plum cultivars, at the "Radmilovac" Experimental Estate of the Faculty of Agriculture in Belgrade. The two-year research (2005-2006) was focused on following characteristics: twig length, number of fruit and vegetative buds and their ratio, as well as the thickness of a year-old shoots and the length of internodes. In the year-old shoots, the average values of the studied indicators varied within the intervals given here: the length ranged from 46.9 cm (Italian Prune) to 71.6 cm (Čačanska Lepotica) the thickness ranged from 6.2 mm (Valjevka) to 8.2 mm (Pacific); the length of the internodes was between 17.9 mm (Zimmer’s Frühzwetsche) and 28.9 mm (Victoria). The number of fruit buds present in the fruits was relatively low - it varied per meter of length from 3.1 (Jelica) to 35.8 (Čačanska Rodna). The average length of spurs was from 1.5 cm (Herman) to 3.8 cm (Italian Prune). The number of fruit buds per 1 m of length in two-year old twigs was comparatively higher, compared to one-year old shoots, and was in the range of 35.3 (Imperial) to 145.8 (Bluefree). The displayed results indicate that in the plum the fruit buds are considerably more present on spurs than on shoots. Cultivars with a higher number of fruit buds per unit length (such as Bluefree, President, Zimmer’s Frühzwetsche, Stanley and Čačanska Rodna) require severe pruning in order to achieve better quality fruits and prevent the stripping of branches in the crown interior. Unlike them, in cultivars that have a lower number of fruit buds per unit length (Imperial, Jelica Victoria, Italian Prune, Pacific), a lower intensity pruning can be applied.

Kod 20 sorti šljive proučavane su morfološke osobine rodnih grančica (dužina broj cvetnih i vegetativnih pupoljaka i njihov odnos) sa ciljem utvrđivanja sortno specifične rezidbe. Rodne grančice su klasifikovane u dve grupe: duge i kratke. Za većinu proučavanih osobina utvrđene su značajne razlike kako između sorti, tako i između godina ispitivanja. Sorte sa većim brojem cvetnih pupoljaka po jedinici dužine zahtevaju jaču rezidbu, dok se kod sorti sa manjim brojem cvetnih pupoljaka može primeniti rezidba slabijeg intenziteta.