Comparison of some morphological and physiological characteristics of six olive graft combinations under drought stress

In order to investigate morphological and physiological responses of six olive graft combinations to drought, this potting research was done in factorial experiment based on completely randomized design with four replications under greenhouse conditions in the University of Tehran, Karaj during 2015-2016. The first experiment included control (field capacity), water stress (permanent wilting point) and recovery (re-watering) with four replications that traits such as relative water content (RWC), cell membrane injury (CMI), leaf dry weight (LDW) and turgor weight/dry weight (TW/DW) were investigated. The secondary experiment included control (field capacity) and water stress (permanent wilting point) treatments that many morphological traits including lateral shoot number (LSN), leaf area (LA), main stem growth length (SL), root length (RL), root dry and fresh weight (RDW and RFW) were calculated. Variance analysis results showed that studied rootstocks had significant effect on all the investigated traits in the first experiment. In the second experiment, rootstock “Koroneiki” showed the highest LA, SL, RDW and RL whereas rootstock “Arbequina” owned the most LSN. Among the studied olive grafting combinations, Co/Ko had better performance than other grafting combinations under water deficit. Thus, that combination can be considered more. Since the current study is a pot-based research, the results presented are not applicable to the fields especially in the areas experiencing drought and cold winter tensions. Therefore, it is necessary to conduct complementary investigations on the related characteristics in the field conditions and then it might be advisable for practical grafting at olive orchards in Iran.