Nature of gene action, heterosis and inbreeding depression of yield and yield component traits in squash (Cucurbita pepo, L.) [electronic resource].

Includes references.

The genetic materials used in the present investigation included five parental varieties of squash. These five varieties were crossed according to a complete diallel crosses mating design to produce 20 F I, Ir hybrids and their.20 F 2. 2r generations. All genotypes were evaluated in a randomized complete blocks design. The obtained results could be summarized as follows: Tests of significance of the mean squares of all 45 genotypes showed highly significance for all studied traits. The parental variety Eskandarani (P1) showed the highest mean for number of fruits/plot, fruits yield/plot (kg) and fruits yield/plant (kg), whereas Zucchino striato d'italia (P3) was the highest parent for first picking date, fruit length (em) and fruit shape index. The performances of the F1 and Fir hybrids were variable and there was no hybrid that gave the best performance for all studied traits. However, most F 1 hybrids exceeded their parental varieties. The estimated values of heterosis over the mid-parents (HM,p,%) showed highly significance for all studied traits and ranged in FI hybrids from - 9.43 to 19.2% for fruit diameter (cm) and fruits yield/plot (kg), respectively. IiI the case of heterosis over mid-parents versus F1. 1r hybrids the estimated values ranged from - 6.74 to 19.4% for fruit diameter (cm) and fruits yield/plot (kg), respectively. Whereas, the estimates of heterosis versus the better parent (H B,P, %) were highly significance for most studied traits. Concerning hcterosis (H B.P. F1.1 r), the obtain values ranged from - 21.36 for fruit diameter (cm) to 7.38% for first picking date. On the other hand, the results

Summary in Arabic.

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