Manifestation of Heterosis and The Role of The Genetic Parameters Associated with It for Some Vegetative Traits in Squash (Cucurbita pepo, L.)

Document Type : Original Article

Authors

1 Dept. of Genetics, Faculty of Agric. Mansoura University, Egypt.

2 Vegetables Breeding Department, Horticulture Res. Inst. (HRI), ARC, Giza, Egypt.

3 Biology Dept., Fac., of Arts and Science- Rafha, Northern Border Univ., Saudi Arabia,91431 Vegetable Breeding, Horticulture Inst., ARC, Giza, Egypt. 12619

Abstract

The main objectives of this investigation were to determine the amounts of heterosis versus the mid-parents and the better parent, nature of gene action and heritability in both broad and narrow senses. Seven squash varieties belong to the species (Cucurbita pepo, L.), were crossed to obtain 42 F1,1r hybrids according to a complete diallel crosses mating design.
The results revealed that the mean squares of genotypes which included seven parental varieties and their F1,1r hybrids were highly significant for all vegetative traits. The results also cleared that the mean values showed that no specific parent was superior for all vegetative traits.
The results indicated that the parents P1 and P6 seemed to be the best combiner for vein length (V.L.cm); number of leaves per plant (No.L./P.); leaf area (L.A.cm2); fresh weight per plant (F.W./P.g) and dry weight per plant (D.W./P.g). Meanwhile, the GCA effects were found to be significant and positive for mostvegetative traits. The parental varieties P3, P6 and P7 were the best combiners for the ratio of chlorophyll in leaves (Chl.).
The estimates of heterosis versus mid-parents showed highly significant values for all studied traits. The estimates of heterosis versus better parent showed highly significant values for most vegetative traits. The results showed the importance of general and specific combining abilities. GCA was larger than their corresponding estimates of SCA for vegetative traits. Reciprocal effects (r) were significant for most studied traits. Estimation of genetic parameters showed that the additive genetic variance was very important for most studied traits. The inheritance of these traits was mostly governed by additive genetic variance rather than non-additive and cytoplasmic genetic factors. In the same time, the estimates of heritability in broad sense were larger in magnitudes than their corresponding values in narrow sense.

Keywords

Main Subjects

Files

Share

How to cite

Statistics