Dissecting Genetic Variability and Combining Ability for Salt Tolerance in Rice Based on Morpho-Physiological Traits

Rice is a highly nutritious cereal crop, but salinity stress is a notable cause of its yield reduction. This study aimed to evaluate the combining ability of rice genotypes for morpho-physiological and yield-related traits under normal and salinity stress conditions. A total of 18 F₁ crosses, derived from 9 parents using a line × tester design, were evaluated in the field under salinity stress of 5 dSm⁻¹ and different morpho-physiological and yield-related traits were recorded. The general combining ability (GCA) and specific combining ability (SCA) through line × tester analysis were performed for data analysis. The outcomes of combining ability analysis indicated that in the inheritance of the most of the studied parameters, both additive and non-additive gene action were involved. Combining ability analysis revealed that under both conditions, Basmati 198 (line) and Basmati-Pak (Tester) were the best general combiners for most characters. Among crosses, Shaheen Basmati × Basmati Pak performed best for most of the features under normal conditions while, Super Basmati × KSK-282 and Bas-198 × KS-282 exhibited superior performance under salinity stress. These two crosses may increase for later generations to select transgressive segregants to develop salinity tolerant rice cultivars. The identified superior general and specific combiners can serve as valuable genetic resources in breeding programs aimed at developing high-yielding and salinity tolerant rice cultivars.