Selection of Salt- tolerant Triticale (X triticosecale Wittmack) and Genetic Variation Assay for Agronomic and Physiological Traits

Salinity is a major limiting factor of growth and grain yield in most crop plants. In the present study, the response of 12 triticale genotypes, 3 wheat commercial cultivars and a rye genotype to four levels of salinity (1:1 ratio of NaCl and CaCl2 salts with EC=0, 7, 14 and 21 dS/m) were assayed in a pot experiment. Salt stress was applied at the four-leaf stage. Variations in two sets of agronomic and physiological traits were analyzed. Most of triticale genotypes had higher grain yield than wheat and rye genotypes under saline conditions. K+/Na+ discrimination ratio which explained 61.7% of the total grain yield variation in linear regression analysis was higher in most of triticales compared with wheat genotypes. Correlation analysis indicated that awn length had the highest correlation with grain yield. Acute angle between grain yield and K+/Na+ discrimination vectors in principal components analysis showed tight association of these traits under salt stress levels. Calculation of genotypic coefficients of variation indicated the existence of higher genetic variation for K+/Na+ (19.82%), awn length (21.64%) and grain yield (26.55%) compared with maturity (4.72%) and total protein (4.63%). Cluster analysis results indicated that TRT808 and TRT806 joined in second group in tree dendrogram under salt stress conditions. This group had higher grain yield mean and K+/Na+ discrimination ratio and its genotypes matured earlier compared to other genotypes. Overall, it can be concluded that triticale performed better than wheat under different levels of salt stress. High genetic variation for some of salt stress- adaptive traits provides the opportunity for production of high-yielding triticales.