The relationship between the end of the vegetation period and fruit properties in the walnut population in Eastern Serbia

The main objective of the study was to examine the walnut population from the region of Eastern Serbia for determining the relationship between the end of the vegetation period and fruit properties (fruit weight, kernel percentage, oil and crude protein contents). The walnut trees showed highly significant differences in the tested parameters. The walnut population was dominated by trees with a medium end of the vegetation period, moderate resistance to low temperatures (39.5%) and very small fruits (23.5%). The fruits of these trees had ? high kernel percentage (15.8%) and moderate oil and crude protein contents (25.8% and 38.3%, respectively). Contrary, the walnut population comprised the fewest trees of late ending of the vegetation period, with extremely large fruits (0.1%), exceptional kernel percentage (0.2%) and pronouncedly high oil and crude protein contents (0.07% and 0.5%, respectively). The studied walnut trees show great variability in the date of the end of vegetation and fruit properties, which indicates a high potential of the population in the selection of new genotypes, and the necessity for their conservation for further breeding, propagation and commercial cultivation.