Generation mean analysis to study the genetics of fruit yield and yield attributing traits in bitter gourd

Abstract

Bitter gourd (Momordica charantia L.), is a prized cucurbitaceous vegetable of the tropics, having high present-day demand along with higher future potential. Keeping the need for high yielding genotype, the present study was performed using the observations from six generations [Parent-1 (CBM-12), Parent-2 (Pusa Purvi), F1, F2, Back Cross 1 (BC1) and Back Cross 2 (BC2)]. The Generation mean analysis revealed that F1 showed intermediate performance of Parent 1 and Parent 2, while few traits showed incomplete dominance. There was lower occurrence of inbreeding depression. Using the scaling and joint scaling test, it was revealed that for fruit length, the additive [d] (6.08) effect was significant and higher than the dominance [h] effect. A significant additive [d] effect was also observed for the fruit shape index (1.75) and fruit weight (45.45). The magnitude of the dominance × dominance [I] effect was higher than the other two epistasis interactions (i.e. additive × additive [i] and additive × dominance [j]) in the majority (nine out of thirteen) of the traits. It was evident that yield is a complex and polygenic trait governed by many genes in a cumulative manner showing both additive (predominant) and non-additive gene interaction. The existence of epistasis with duplicate type predominant, as compared to complementary, in genetic control of all the traits studied, was also revealed.