Genetic analysis of salt tolerance in early growth stages of rapeseed (Brassica napus L.) genotypes

Genetic parameters for different characteristics related to salinity tolerance were estimated using 8 x 8 diallel crosses in rapeseed (B. napus). Salt stress was induced by adding incremental levels of NaCl to Hoaglands solution in a sand culture until electrical conductivity of 12.9dSm⁻¹ was attained. Analysis of variance revealed significant general and specific combining ability mean squares for all studied characteristics, indicating the involvement of both additive and non-additive gene actions in the inheritance of characters. High ratios of narrow-sense heritability estimates were observed for Ca²⁺, K⁺, Na⁺, K⁺/Na⁺, Ca²⁺/Na⁺, and stress tolerance index (TOL), indicating the prime importance of additive effects in their genetic control. Significant positive correlations were observed between shoot dry weight and Ca²⁺/Na⁺ (0.531**), and K⁺/Na⁺ (0.562**). The results revealed that the parents BL2, Ceres, and Shiralee and the crosses Falcon x BL2, BL2 x Ceres and Ceres x Shiralee were superior to perform effective selection for salinity tolerance in rapeseed.