Evaluating salt tolerance in doubled haploid barley lines using a multivariable screening approach

Abstract

Salt stress is one of the major environmental factors limiting cereal productivity in worldwide agriculture. Evaluating and selecting salt tolerant genotypes are an effective approach to overcome yield losses. This study aimed to characterize and compare phenotypic variability among doubled haploid (DH) barley lines and their parent under different salinity conditions (T1 = 0, T2 = 3, and T3 = 6 g.L −1 NaCl). The DH lines were produced by in vitro selection callus in a regeneration medium supplemented with 5 g.L −1 NaCl. Fifteen measured traits were assessed including physiological, biochemical, and agro-morphological traits. Biplot analysis was used to visualize the relationships among the studied traits and to evaluate the relative performance of each genotype. Pearson's correlation followed by stepwise and path analysis were then performed successively to identify appropriate criteria that most influence grain yield. The results showed a wide range of variation for the measured traits, indicating the existence of a phenotypic variation between the tested genotypes. Salinity significantly affected the parent more than the DH lines. Stepwise regression analysis indicated that 99% of the variation in grain yield was explained by K + /Na + ratio, number of fertile spikes per plant, number of grains per spike, plant height, and proline content. However, the path coefficient revealed that number of fertile spikes per plant and number of grains per spike were indicative of salt tolerance in barley. Based on stepwise and path analysis results, the tested genotypes were ranked using salt tolerance index. The salt tolerant DH lines could be recommended as novel genetic resources in breeding programs. • A set of agro-physiological and biochemical traits was used to differentiate salt tolerant genotypes between doubled haploid barley lines and their parent. • Salt stress caused significant increase in proline, Na + , and decrease K + , stomatal conductance, and chlorophyll contents. • Salt stress reduced significantly yield and yield components. • Fertile tiller number, number of grain per spike, and K + /Na + ratio were the major traits influencing grain yield. • The doubled haploid barley lines exhibited superiority in salinity tolerance compared with their parent.