Effects of deficit irrigation on vegetative growth, yield and fruit quality in three olive oil cultivars

Current research was carried out to determine the effect of deficit irrigation on vegetative and reproductive characteristics of 14 years old olive oil cultivars named 'Roughani', 'Amphisis' and 'Mission' in Dallaho Olive Research Station of Sarepole Zehab under three irrigation regimes during 2014. Irrigation treatments were included 100 % ETp irrigation (control), deficit irrigation 60 % ETp during the growing season (continuous deficit irrigation) and regulated deficit irrigation (deficit irrigation 60 % ETp during the growing season plus no irrigation during periods of pit hardening and color change). Results indicated lower growth in deficit irrigation treatment. However, higher fruit weight, fruit length, pulp fresh and dry weight, fruit moisture percentage, pit dry weight and pit length were obtained in regulated deficit irrigation treatment in compared to continuous deficit irrigation. There were no significant differences between treatments for pulp/pit dry weight ratio, pulp percentage and dry and oil content in fresh weight. Oil percentage in dry matter was significantly different between irrigation treatments, where the highest oil percentage in dry matter (38.67%) was found in ̒Roughani̕ cultivar under continuous deficit irrigation. Also, this cultivar had the higher oil yield in hectare in comparison to those of 100 % ETp irrigation and regulated deficit irrigation. In ̒Amphesis̕ cultivar, there was no significant difference in oil yield between 100 % ETp and regulated deficit irrigation treatments. Generally, there were different responses between cultivars to irrigation treatment and cv. Amphissis can be introduced as tolerant cultivar under regulated deficit irrigation. Vigorous cultivar (Mission) was more affected under deficit irrigation.