Fruit characteristics in walnut tree population in relation to growing season onset

Abstract

The objective of walnut selection is to obtain promising genotypes characterized by later growing season onset, shorter period of vegetation, resistance to diseases, stable fruit productivity and high fruit quality. Aiming at obtaining genotypes with favorable properties, in five localities of Eastern Serbia, where walnut is widely grown, we studied the correlation among growing season onset on the one hand, and major pomological properties and fruit quality on the other. In the studied population, trees with early growing season onset and fruit mass up to 8.0 g (30.1%) were predominant, whereas those with late growing season onset were in minority, fruit mass ranging from 10.1 to 12 g (0.07%). Kernel ratio was highest in the former (20.69%), and the lowest in the latter (0.07%). Similar was observed in oil and raw proteins content in kernel which was highest in fruits of early trees (33.62%, 47,55%), while it was remarkably lower in late ones (0.72%, 0.49%). The obtained results suggest that the studied population was dominated by early trees and unfavorable or less favorable fruit properties. In spite of that, we evidenced some trees with favorable properties which can be used in breeding as donors of useful genes.