Division of Genetics, Indian Agricultural Research Institute, New Delhi-12
Multiple regression equations expressing grain yield (Y) in terms of spike length (X1), spike girth (X2), 500 grain weight (X3), number of ear bearing tillers (X4), grain density (X5); and also yield (Y) in terms of protein content (X6), calcium (X7), phosphorus (X8), iron (X9) and ash content (X10) of grain, were fitted to 41 mean values of S0, S1 top crosses of one experiment and 81 S0 parents and top crosses of another. The resulting equations were, Y=816.7+ 0.008505 (X4) having R=0.4908 for S0; Y=638.5+0.014952 (X4) having R=0.7926 in S1; and Y=899.9+0.020805 (X1) + 0.1858 (X3)+0.005995 (X4) having R=0.6847 for the agronomic characters of the other experiment. In the case of quality characters observed only in the second experiment, the equation was Y=904.6 -0.06347 (X6) -0.9048 (X10) having R=0.4993. Thus, number of ear bearing tillers was found to be the most potent character for yield and the association in S1 was more pronounced.