Investigation of genetic structure and gene action in bread wheat affected by salt stress

Abstract

In order to study the effect of NaCl salinity on wheat genetic structure and gene action, F1, BC1P1, BC1P2, F2, and F3 generations were produced in the greenhouse by crossing a sensitive bread wheat cultivar (Arta) with the salt tolerant (Bam) parent. A split plot experiment was conducted in greenhouse based on randomized complete block design at 0, 125 and 250 mM NaCl in the sand culture. The three salinity levels (0, 125 and 250 mM NaCl) were arranged as the main plots and seven generations were included in the subplots. Agronomic traits including plant height and shoot biomass together with physiological traits such as KNa -1 discrimination ratio and electrolyte leakage were measured. Regression method was used to estimate the effects and variances. Generation means were reduced for all traits in the salt stress condition except for electrolyte leakage which was increased in this environment. Only additive effects were present for plant height at 125 mM NaCl and for KNa -1 at 250 mM NaCl. Furthermore, both additive effects and additive by additive epistasis governed the control of plant height at the non-saline condition. High broad sense heritability and moderate narrow sense heritability were observed for most of the measured traits under different salinity levels. In conclusion, the notable amount of heritable variation obtained for several characters, especially KNa -1 , suggest the possibility of developing genotypes having suitable agronomic characters and the traits related to salt tolerance in the F2 population under study.