screening of almond hybrids for drought tolerance using some morphological and physiological traits

In this research, twenty-two selected almond hybrids with their parents ‘a1-99’ (drought-sensitive) and ‘tuono’ (relatively tolerant against drought), were investigated for screening drought tolerance using some morphological and physiological traits. this research was carried out in a complete randomized design with three replications at the temperate fruit research center of horticultural sciences research institute (hsri) in years of 2014 and 2015. the results showed that by applying severe drought stress (30% fc), some morphological and physiological characteristics such as chlorophyll index (chi), relative water content (rwc) of leaf decreased, while electrolyte leakage (el) and quantum efficiency of the photosystem ii (fv/fm) increased. according to results, there were significant differences among genotypes, for example range of fv/fm among the selected hybrids varied from 550 to 879. frequency of drought tolerance showed that 77. 27% of hybrids were susceptible to relatively susceptible and 22.72% were tolerant to relatively tolerant. finally, according to the results from this study, ‘dt19’ hybrid was recognized as the most sensitive and ‘dt1’ hybrid was known as the most tolerant hybrid that could be introduced as promising and tolerant to drought stress for utilizing in the breeding programs.