Abstract

                                A study was made to assess the extent of oxploitable heterosis in a 7 x 7 diallel. The results indicated that almost all combinations involving IR 8 as one of the parents pos- sessed high mean and significant heterosis for yield but none of thec ombinations excelled it, indicating non-existence of exploitable heterosis with the parents under study. Similarly for other yield components like productive tillers per plant, number of grains per panicle and 100 grain weight, there was no standard heterosis at exploitable level. These results show that selection of parents is a critical step for successful hybrid rice programme.

Key words :