Heritability and number of genes controlling seed yield in bottle gourd

Abstract

Bottle gourd [Lagenaria siceraria (Molina) Standley] is an important tropical specie characterised by a wide diversity and a low yield, mainly due to no selection for improved varieties. Selection for a particular trait depends on the relative importance of genetic and nongenetic factors influencing the expression of phenotypic differences among crop population. The objective of this study was to examine the genetics basis of seed yield and yield components, by crossing oleaginous type and calabash-type of bottle gourd [Lagenaria siceraria (Molina) Standley]. The parental lines (P1 and P2), with the respective hybrids F1 and F2 generations, were grown in two contrasted locations in terms of pedoclimatic conditions.  Results showed no significant difference between the two locations for studies traits (P=0.06).  For seed yield per plant, 100-seed weight per fruit, and number of seeds per fruit, a positive hypothetical heterosis was observed when calabash type was a maternal parent. Negative real heterosis was observed in all studied traits. For all traits, the genetic variance was higher than the environmental variance in the most of the crosses, implying greatest genes action in the expression of studies traits. Heritability was medium for fruit weight (mean, 42.12%) and seed number per fruit (mean, 47.36%). But for 100-seed weight (mean, 61.00%) and seed yield per plant (mean, 53.28%) high heritability were observed. The minimum number of genes that controlled the expression of 100-seed weight (0.58), seed yield per plant (1.58) and number of seeds per plant (0.98) was low (close to 1). These observations suggest that distinct genotypes for interest characters would be fixed by using a small number of selfing generations (F3 to F4) in West African bottle gourd.

Key Words: Heritability, heterosis; Lagenaria siceraria, number of genes, seed yield