The influence of rootstocks on the sensitivity of flower buds to frost and the main properties of the ‘Carmen’ sweet cherry cultivar

The study examined the influence of five vegetative rootstocks on the flower bud sensitivity to frost during the period of ecological dormancy and the most important biological and pomological properties of the ?Carmen? sweet cherry cultivar. The ?Carmen? cultivar was grafted on the following rootstocks: ?Colt?, ?Gisela 5?, ?Gisela 6?, ?MaxMa 14? and ?Oblacinska cherry?. Winter frosts occurred during the ecological dormancy of sweet cherry trees. The intensity of frost was between -5?C and -7?C. The percentage of damaged and non-damaged flower buds per fruiting branch was determined by counting (50 flower buds per tree were taken from every part of the canopy and fruiting branches). The highest rate of damage of flower buds was in trees grafted on ?Oblacinska cherry?, an average of 77.2% of flower buds, while the lowest was observed in trees grafted on ?MaxMa 14?, an average of 24.3% of total flower buds. The significantly higher sensitivity of flower buds was found in spur fruiting branches compared to lateral fruiting branches. The fruits of the ?Carmen? cultivar had the earliest ripening on rootstocks ?Gisela 5? and ?Oblacinska cherry?. The ?Carmen? cultivar had the highest yield per tree on the ?MaxMa 14? rootstock, while the lowest yield rate was observed in ?Oblacinska cherry?, 5.4 kg and 1.9 kg, respectively. The highest mass of fruits was noticed in trees grafted on ?Gisela 6?, an average of 11.6 g, while the smallest was recorded in trees grafted on ?Gisela 5?- an average of 9.4 g.

UTICAJ PROREĐIVANJA PUPOLJAKA NA KVALITET PLODOVA TREŠNJE (Prunus avium L.) SORTI ‘KORDIA’ I ‘SWEETHEART’

Thinning the buds of May flowers, as an pomotechnical measure, can significantly increase the average fruit size. The paper presents the results of thinning of buds of cultivars "Kordia" and "Dušice" on rootstocks "Gisela 5" and "Gisela 6" grown in the system of Vogel spindles. The examined cultivars reacted positively to the thinning of the buds by increasing the fruit weight, which was especially expressed in the cultivar 'Kordia'. Thinning of the buds had a positive effect on the presence of marketable fruits, although not to a significant extent.

Planting density and size-controlling rootstocks influence the performance of Montmorency tart cherry (Prunus cerasus L.)

Two multi-year experiments were conducted to determine the influence of planting density and rootstocks on the performance of Montmorency tart cherries (Prunus cerasus L.). Using a constant between-row spacing of 4.5 m, three in-row tree spacings of 4, 3 and 1.5 m were tested with five rootstocks: Weiroot 13, Gisela 6, Krymsk 6, Krymsk 7, and a Prunus mahaleb control. In a second experiment, the comparative effects of five rootstocks spaced 4.5 m × 1.35 m were evaluated: (i) P. mahaleb, (ii) Weiroot 10, (iii) Weiroot 13, (iv) Weiroot 72, and (v) Weiroot 158. With higher tree density, yields increased and tree vigour declined. At higher densities, Weiroot 13 was up to 43% and Gisela 6 16% smaller than Mahaleb, whereas Krymsk 6 and 7 were similar in size to Mahaleb. At the highest density, Mahaleb reduced tree size by 20%. After 7 yr, tree mortality on Krymsk 6 and 7 was greater than the other rootstocks, as was the number of root suckers on Krymsk 7. Cumulative yields, yield efficiency, fruit quality characteristic, and light interception were also markedly influenced by planting density and rootstocks. Overall, evaluated rootstocks ranged in size control from slight to semi-dwarfing, and several showed promise in terms of their induction of high-yield precocity and yield efficiency of the scion. Weiroot selections and Gisela 6 had the greatest beneficial effects on productivity and yield efficiencies. Under experimental conditions, Krymsk 6 and 7 were unsuitable because of their lower cumulative yields and high rate of mortality, respectively.