Heterosis and Combining ability Analysis in Quality Protein Maize Inbred Lines

In the present investigation, 42 crosses of quality protein maize (QPM) inbred lines (L1, L2, ….L14) with three testers (T1, T2 and T3) were evaluated against a QPM check , Shakti-1 in a randomized complete block design with 3 replications at G.B. Pant University of Agriculture and Technology, Pantnagar, India during Kharif, 2004. Observations were recorded on days to 50% tasselling and silking, plant height, ear height , ear length, ear diameter, kernel rows per ear, 100-kernel weight, grain yield and incidence of BLSB and BSDM. Protein, lysine and tryptophan contents were also estimated. The characters under study showed highly significant genotypic differences and wide range of variation in mean values. The crosses, L8 x T1, L1 x T3, L8 x T2, L5 x T2, L5 x T1, L2 x T1, L13 x T3, L3 x T1 and L8 x T3 revealed significant positive heterosis for grain yield. The gca effects of the parents showed that among lines, L8 was good for ear length, ear diameter, kernel rows per ear, 100-kernel weight and grain yield. L1, L12 and L13 were the other good general combiners. Based on the sca effects, L3 x T1 and L3 x T2 were good for ear length, ear diameter, kernel rows per ear, 100-kernel weight and grain yield. L14 x T3, L1 x T3, and L4 x T1 were the other specific cross combinations good for different characters. All the inbred lines and their crosses were moderately resistant to both the foliar diseases, BLSB and BSDM. The cross, L13 x T3 superceded the standard check for protein (9.74%), lysine (3.24%) and tryptophan (0.81%).