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.