Influence of Pruning and Interspecific PrunusHybrid Rootstocks on Tree Growth, Yield and Fruit Size of Apricot

Abstract

In 1991 a trial was established to determine the effect of two interspecific hybrid rootstocks and two pruning systems on the growth and fruiting of 'Sundrop' apricot. The rootstocks evaluated were Haggith (standard), M800 ( Prunus besseyix P. sibirica), and Yuksa ( P. besseyix P. armeniaca). The two pruning systems were Central Leader and Spanish Bush. At the end of the experiment trees pruned to the Central Leader were the tallest and had the largest canopy spread. No difference in trunk cross-sectional area was found between the two pruning systems. There was no difference in tree height among the rootstocks, but trees on Haggith had the largest canopy spread and trunk-cross-sectional area and trees on M800 were the smallest. Yield was not affected by pruning; however, fruit from the Spanish Bush system were the smallest. Trees on Haggith had the highest yield and the largest fruit. It appears that the Spanish Bush pruning system may be a satisfactory system for apricots. The lower yields and smaller fruit of trees on M800 suggests that it should not be recommended as an apricot rootstock.