Effects of Regulated Deficit Irrigation Regime on Vegetative and Pomological Characteristics and Yield of Table Olive Konservolia Cultivar in Field Condition

Olive (Olea europaea L.) is one of the every green trees that tolerance to Drought. Olive is an economically important species of the Mediterranean area, so understanding the mechanisms by which olive plants face drought stress under environmental conditions is essential for the improvement of olive yield and oil quality. Olive (Olea europaea L.) is one of the fruit trees which become important in the Iranian fruit industry at the near future. It seems that olive tree has potential for resistance to drought conditions of semi-arid regions of Iran. There is a high production potential for olive tree in many regions of Iran. Regulated deficit irrigation is an optimizing strategy under which crops are allowed to sustain some degree of water deficit and yield reduction. During regulated deficit irrigation the crop is exposed to certain level of water stress either during a particular period or throughout the growing season. The main objective deficit irrigation of is to increase water use efficiency (WUE) of the crop by eliminating irrigations that have little impact on yield, and to improve control of vegetative growth (improve fruit size and quality). The resulting yield reduction may be small compared with the benefits gained through diverting the saved water to irrigate other crops for which water would normally be insufficient under conventional irrigation practices. This study was aimed to investigate the effect of regulated deficit irrigation regime on vegetative and pomological characteristics and yield of table olive konservolia cultivar in field condition.

This experiment was conducted in Dallaho Olive Research Station (Geographical characters was longitude of 45˚, 51΄ E and latitude of 34˚, 30΄ N and the height of sea level 581m) located in Kermanshah province. An experiment was used based on a randomized complete block design with three replications. Adult table olive Konservolia cultivar was uesd. Each experiment unit consists of Three trees. Vegetative and reproductive traits were evaluated according to I.O.O.C. descriptors. Six irrigation regimes including of full irrigation (as control), regulated deficit irrigation (100% of full irrigation during growing season plus 25% irrigation during pit hardening, regulated deficit irrigation (100% of full irrigation during growing season plus 75% irrigation from Start pit hardening to harvesting), irrigation in three stage (before flowering, pit hardening and before Harvesting , 60% of full irrigation (continuous deficit irrigation) and no irrigation (Rainfed). To elevate the effect of irrigation regimes, some growth vegetative traits measured at the end of growth season including current-season shoot growth and current-season shoot diameter as well as some fruit traits including fruit and oil yield, fruit weight, fruit length and diameter, pulp fresh and dry weight, fruit moisture percent, pulp percent were measured. Collected data were analyzed with SAS program.

Obtained results showed that the highest fruit yield, oil yield, fruit weight, fruit diameter, pulp fresh and dry weight, pulp percent were observed at full irrigation and regulated deficit irrigation (100% of full irrigation during growing season plus 25% irrigation during pit hardening, but the lowest one found at Rainfed. There was no significant difference between deficit irrigation in three stage and 60% of full irrigation (continuous deficit irrigation) in fruit yield, oil yield, fruit weight, fruit diameter, pulp fresh and dry weight. The water use efficiency of fruit yield of T4 and T2 was higher than 100ETc and other treatments. Overall, the results showed that RDI during fruit pit hardening could increased water use efficiency, whitout reduce fruit yield, oil yield, fruit weight, fruit diameter and pulp fresh and dry weight.

In the arid and semi arid as well as sub-tropical regions, water shortage is a normal phenomenon and seriously limits the agricultural potential.Therefore, under irrigation or rain-fed conditions, it is important for the available water to be used in the most efficient way. Regulated deficit irrigation is an optimizing strategy under which crops are allowed to sustain some degree of water deficit and yield reduction. During regulated deficit irrigation the crop is exposed to certain level of water stress either during a particular period or throughout the growing season. The main objective deficit irrigation of is to increase water use efficiency (WUE) of the crop by eliminating irrigations that have little impact on yield, and to improve control of vegetative growth (improve fruit size and quality). According to the results of this research, it can be concluded thatthat RDI during fruit pit hardening could increased water use efficiency, whitout reduce fruit yield, oil yield, fruit weight, fruit diameter, pulp fresh and dry weight.