Department of Vegetable Science, H.P. Agricultural University, Palampur - 176 062, India.
Abstract: An experiment was conducted to understand the nature of gene effects for yield and its component characters in tomato. Six generations, (P1, P2, F1, F2, B1 and B2) of Hawaii 7998 x BT-18, Hawaii 7998 x EC 191536 and BT-18 x EC 191536, derived after crossing the bacterial wilt resistant parents, were studied following 3-parameter model of Cavalli (1952) and 6-parameter model of Jink and Jones (1958). Duplicate epistasis with relatively higher magnitude of [l] interaction (+) was observed for marketable yield per plant and number of marketable fruits per plant in Hawaii 7998 x BT-18 and BT-18 x EC 191536, thus suggesting a need for exploitation of hybrid vigour or intermating followed by selection in later generations, in these crosses. Whereas, the presence of additive effects [d and i] in Hawaii 7998 x EC 191536 indicated the importance of simple pedigree selection. For the traits related to earliness (days to 50% flowering and days to first harvest), pedigree selection in BT-18 x EC 191536 and pedigree selec
