Combining ability and heterosis of drought tolerant maize (Zea mays L) under stress conditions

Different drought tolerant genotypes were used to produce crosses in L x T design for assessment of combining ability of genotypes and heterosis of crosses for various traits. The mean sum of squares were significant for most of the traits except relative water content. Lines showed significant differences for most of the traits, particularly for anthesis to silking interval and 100-grain weight under water stress. Testers showed significant differences for days to 50% anthesis, days to 50% silking and 100 grain weight (g) under both the situations. The interaction between lines and testers was significant for shelling percentage and chlorophyll content at both the stages under normal condition and for cob length (cm), number of kernels per row and chlorophyll content at 90 days under stress. The combining ability status of parents revealed that All-Rounder, NK 6240 and Rajkumar showed high gca status for all the traits both under stress and nonstress situations, among lines. Whereas among testers, CI 4 and Hyd Sel 17 showed high gca status for majority of the traits. The crosses viz., NK 6240 x CI 4, All-Rounder x Hyd Sel 17, Rajkumar x CI 4 and Rajkumar x Hyd Sel 17 recorded positive heterosis for grain yield (kg ha −1). The parents of these crosses showed high gca status for many of the traits under stress and normal conditions and they could be utilized for the development of diverse populations for the isolation of inbred lines for specific environment.