Gene effects studies in sponge gourd for earliness, yield and its component traits

Gene action was studied in indigenous and under exploited vegetable sponge gourd utilizing six high yielding F(1)s, their F-2, B-1, and B-2 generation population following generation mean analysis. Preponderance of additive gene effects was noticed for earliness, while dominance gene effects for number of fruits per plant, fruit length, fruit weight and total yield per plant. High dominance effect was observed in crosses DSG-6 X PSG-9 (41.22), DSG-6 X NSG-1-11 (36.60) and DSG-7 X NSG-1-11 (27.95) for number of fruits per plant, while DSG-7 x NSG-1-11 DSG-6 x Pusa Sneha and DSG-6 X CHSG-2 for average fruit weight (69.00, 46.33 and 41.33, respectively). The dominance component was comparatively less for total yield per plant and DSG-6 x PSG-9 (6.64), DSG-7 x NSG-1-11 (5.47) and DSG-6 X NSG-1-11 (5.43) exhibited highest dominance effect among the crosses. Additive x additive interaction was higher in magnitude in desirable positive direction for total yield per plant and DSG-6 X PSG-9 (3.53) exhibited the highest followed by DSG-7 X Pusa Sneha (3.38) and DSG-7 X NSG-1-11 (3.01). Majority of the crosses showed duplicate type of epistasis. One cross DSG-6 x CHSG-2 showed complementary epistasis indicating the positive gain in yield enhancement through heterosis breeding. The study suggested the need of adoption of cross specific (parent specific) breeding programme for different traits. Simple mass selection would result in progress for characters governed by additive gene effects like earliness, heterosis breeding for characters governed by dominance gene effects like number of fruits and yield per plant and breeding plan based on restricted selection by way of intermating the most desirable segregants followed by selection and/or diallel selective mating system would be most appropriate for characters where duplicate epistasis was predominant.