ASSESSING GENE ACTION AND COMBINING ABILITY IN Brassica napus L. UNDER DROUGHT STRESS CONDITIONS, AN EFFORT TOWARDS BREEDING RESILIENT VARIETIES

Abstract

Drought stress is the limiting factor in productivity as well as quality of any crop. Drought stress effects are crucial in Brassica napus but severity depends on the duration, intensity and developmental stages.  İn the present study, eight drought tolerant lines and three drought sensitive testers were crossed in the line × tester fashion. Developed germplasm accesions with their parents were evaluated under standard and drought stress conditions in RCBD having split plot arrangements. Various qualitative and quantitative parameters were recorded. Among the parents, ZMR-2, Dunkled, and Garchi exhibited potential based on their general combining ability (GCA) under both control and drought stress conditions.. The best cross combinations, identified through significant positive values for specific combining ability (SCA), included ZMR-2 × ZMR-18, Winner × ZMM-12 and Garchi × ZMR-18 under control and drought stress treatment T₁. Similarly, G-51 × ZMR-18, Dunkled × ZMR-18, and DGL × ZMR-18 performed well under drought stress treatment T2. GCA variance surpassed the SCA varinace, depicting the presence of additive gene action in studied material. So, these crosses could be selected readily without moving towards segregating generations in the future drought breeding programes.