OLIVE ROOTSTOCKS TO CONTROL 'ARBEQUINA IRTA-I18' CLONE VIGOUR - RESULTS FROM A SECOND ONE COMPARATIVE TRIAL

An olive rootstock selection program has been established in order to identify genotypes appropriate to control the vigour of ‘Arbequina-IRTA-i•18’ clone (scion) by grafting. This study is a coordinated program with IFAPA-Cordova, funded by INIA-RTA-2010-00013-C02-C2 research project. Additional rootstock characteristics considered are tolerance to specific soil diseases and performance under different soil conditions. The trial was planted, with drip irrigation, in Constantí (Tarragona, Spain) in 2001 and is complementary to a previous one planted in 2000 in the same site. Experimental design was a randomized complete block with 18 rootstocks and one control own-grafted and five replicates (one tree per rootstock and block). After 10 years of study, results show significant differences for tree vigour between rootstocks. In fact, higher vigour (40% more than i•18 in average) was observed for ‘Empeltre’ and ‘Blanqueta’, while ‘Verdal de Manresa’, ‘Nana’ and ‘Redonda Mora de Toledo’ scored the lower vigour (25% lower than i•18). Yield is higher for most vigorous rootstocks, but differences are still not significant related to own-grafted i•18. Fruit characteristics and oil composition are also discussed as affected by rootstocks.