Experiences with Mazzard and Colt sweet cherry rootstocks in Serbia which are used for high density planting system under heavy and acidic soil conditions

• Seven sweet cherry cultivars on Mazzard and Colt rootstocks were grown in HDP system on heavy and acidic soil.
• Mazzard improved tree growth and yield, whereas Colt promoted fruit quality and leaf nutrient content.
• ‘Stark Hardy Giant’ on both rootstocks had the lowest tree vigor and the highest yield efficiency.
• High variability between rootstocks and among cultivars in leaf nutrients content was found.
• Both rootstocks and all cultivars provoked excessive leaf N and Cu, and deficiency of other nutrients.

From 2008 to 2013 we investigate impact of Mazzard seedlings and Colt rootstock on tree growth, precocity, productivity, gross profit, fruit quality and leaf nutrients level of seven sweet cherry cultivars which are grown at Cacak region (Serbia) on heavy and acidic soil in high density planting system (HDP). Results showed that most of the evaluated traits significantly varied between rootstock and among cultivars. Thus, Mazzard induced higher tree vigor, yield performances, gross profit, flesh rate, fruit acidity, and leaf P and Mn levels, whereas Colt induced higher fruit weight, fruit dimensions, size and shape values, stone weight, ripening index and leaf N, Ca, Mg, Fe and Zn amounts. Regarding cultivars, ‘Stark Hardy Giant’ (‘SHG’) had the lowest tree vigor on both rootstocks, whereas the highest was induced by ‘New Star’ on Mazzard, and by ‘Summit’ and ‘Lapins’ on Colt. Generally, the highest values of yield attributes and financial results were found in ‘Sunburst’ on Mazzard and ‘SHG’ on Colt, whereas ‘New Star’ had the poorest. ‘New Star’ on both rootstocks, ‘June Early’ on Mazzard, and ‘Lapins’ on Colt were cultivars with the better fruit weight and other physical traits, whereas ‘Hedelfinger’ had higher soluble solids content (SSC) and acidity on both rootstocks as compared with others. ‘New Star’ grafted on Mazzard and ‘Lapins’ on Colt showed a tendency to promote higher RI. Cherries of trees grafted on Colt showed higher capacity to accumulate leaf N, Ca, Mg, Fe and Zn, whereas leaf of cherries on Colt had higher P and Mn amounts. High variability among cultivars regarding leaf nutrients content was found. Both rootstocks and all cultivars on them exhibited excessive leaf N and Cu levels, and high insufficiency of other leaf macro- and micronutrients. Colt showed better balanced nutritional values for macronutrients, whereas rootstock impact on this trait for micronutrients was not significant. ‘SHG’ on both rootstocks, in general, is the cultivar with the best balanced nutritional values as compared to others.