Genetic and multivariate phenotypic analyses of some selection indices in pistachio (Pistacia vera L.) cultivars under drought stress conditions

Abstract

Heritability and Genetic Gain are commonly used by plant breeders to estimate the accuracy of a selection index and used for measuring the response to selection. The aim of the present study was the genetic and phenotypic analyses of some physiological traits to identify the most reliable of them for selective breeding of pistachio cultivars under drought stress condition. Nineteen Pistachio (Pistacia vera L.) cultivars with wide range of tolerance to drought stress were collected from across the orchards of Rafsanjan (Iran?s center of pistachio cultivation) and were used in randomized complete block design with three replications under two environmental conditions (normal and water stress) in 2011-2012. The results of genetic analysis showed that high magnitude of phenotypic and genotypic coefficient of variation along with broad sense heritability and genetic gain were estimated in relative water protection (RWP), excised leaf water loss (ELWL), relative water content (RWC) and relative water loss (RWL) under drought stress condition, indicating that the inheritance of these traits can be mainly controlled by additive gene effects followed by reflecting the possibility of effective selection for genetic improvement of these traits. Path analysis revealed that RWP had the highest direct and RWL and WRC indirect effects on YSI. Principal component analysis indicated that selected indices were reliable for classification and identification of drought-tolerant pistachio cultivars and identified RWP, RWC and WRC as the best indicators for screening drought tolerant genotypes.