To investigative the effect of benzyladenine and eliminate of irrigation in winter on vegetative growth
parameters and chemical composition of tree and nut quantitative characteristics of pistachio trees cv.
Kaleh-Ghoochi, an experiment was done in 2010 to 2012 years. In this study, the effect of two irrigation
regimes includes irrigation and non-irrigation in winter combined with three levels of benzyladenine (0,
20 and 40 mg L-1) was investigated. The experiment design was randomized complete block design with
three replications. The data obtained from both experiment analyzed as the combined analysis. Irrigation
treatment was done as similar as common irrigation program in orchard, and in non- irrigation treatment,
there wasn’t irrigation from January to April in both years. Application of benzyladenine treatment was
done at inflorescence buds swollen time. The results showed, 40 mg L-1 benzyladenine had the most
effective on vegetative growth of trees compared with the other treatments. Also benzyladenine
treatments compared with the control had significant increase in the ecophysiological parameters; leaves
biochemical compounds contents, leaves nutrient elements concentration and caused reducing in
percentage of early splitting fruit and bud abscission significantly. Also, results showed that elimination
of irrigation in winter had no significant effect on the mentioned parameters. Thus, based on the results of
this study it seems that elimination of winter irrigation doesn’t have any effect on vegetative growth and
development of pistachio tree, but application of BA in late winter has positive effects.