Department of Genetics, Haryana Agricultural University, Hissar, 125 004, India
Harvest index and its two components, the biological yield and grain yield, were analysed following Griffing's (1956) combining ability approach. The gca variance was significant only in case of harvest index, while sca variances were significant for all the three traits. Higher gca/sca ratio and the estimates for hentability in narrow sense were observed for harvest index than those for the other two traits. The general predictability ratio was near unity for the former, while its estimates were low and far from unity for the latter two components. The estimates of various parameters showed less variation in different environments for harvest index than for the two components. Thus, the harvest index appeared to be a more suitable criterion for selection than the biological yield 0r the grain yield.
