Gene action for yield and quality traits in bottle gourd [Lagenaria siceraria (Molina) Standl.

Abstract

Gene action and their relative contribution in expression of characters is of great importance. Twenty one F1 hybrids were obtained by partial diallel crosses between seven parents to determine the nature of gene action and their relative contribution in expression of characters. Significant values of dominance components Ĥ1 and Ĥ2 for all the traits (except fruit weight for Ĥ2), along with significant values of additive components for number of fruits per plant, T.S.S. and ascorbic acid indicated the importance of both additive and dominance gene action in expression of these characters. However, additive ( ) component was lower in magnitude than dominance components of genetic variation for all the characters which revealed preponderance of dominance component of variance in the expression of fruit yield and its attributes. The average degree of dominance (Ĥ1 / )1/2 involve in the gene action was found as over dominance for all the traits. This suggested that heterosis breeding might be advantageous for improvement of yield and its component traits in bottle gourd. Proportion of genes (Ĥ2/4Ĥ1) in the parents were less than 0.25 for all the traits which showed asymmetrical distribution of loci showing dominance in the inheritance of these characters. The ratio of (4 Ĥ1)1/2 + / (4 Ĥ1)1/2- indicated the excess of dominant genes among the parental strains for most of the characters. The ratio of ĥ2/Ĥ2, provides information about groups of gene exhibiting that minor genes mainly governed the characters except days to first pistillate flower anthesis, node number to first staminate flower anthesis, days to first fruit harvest and fruit weight under study, which may be due to concealing effects of dominant gene with positive and negative effects.