Division of Genetics, Indian Agricultural Research Institute, New Delhi-12
**Present address: Department-of Genetics, Haryana Agricultural University, Hissar.
*Part of a thesis submitted to the Post Graduate School, Indian Agricultural Research Institute, for partial fulfilment of the requirements of a Ph. D. degree.
Performance of some true breeding cultures and their different filial generations has been correlated with four different levels of heterozygosity. From the data reported in this paper, there does not seem to be any linear relationship between the performance and heterozygosity, indicating the presence of epistasis.
