Genetic behavior for yield and its components in summer squash plant(cucurbita pepo L .) treated with amino acids - ( casein hydrolysate )

• 2 Shamil Younis Hassan AL-Hamadany 1 Layth khalid Rashid

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This study, conducted in Nineveh province, Iraq, evaluated the heritability of certain growth and yield traits in four summer squash hybrids: Wissam F1, Private F1, Ha030 F1, and JAZ F1. The study investigated the effects of foliar spraying with amino acids - ( casein hydrolysate ) at five concentrations (0, 0.5, 1, 1.5, and 2 g/L) during the autumn growing season of 2025 at the Agricultural Research Field, College of Agriculture and Forestry, Mosul. The experiment consisted of twenty treatment combinations in a completely randomized block design (RCBD) with three replications. Analysis of variance (ANOVA) showed significant differences among the four hybrids in the mean squares for all studied traits except total leaf chlorophyll content and shoot dry matter percentage, where differences were non-significant. The Ha030 F1 hybrid exhibited the highest significant early fruit yield, while the JAZ F1 hybrid exhibited the highest total yield. The treatment with 2 g/L amino acids ( casein hydrolysate ) resulted in the highest early fruit yield, per-plant yield, total and marketable yields, significantly surpassing those of other hybrids. The highest early fruit yield was observed in hybrid Ha030 F1 plants treated with 2 g/L of amino acids ( casein hydrolysate ), while JAZ F1 plants treated with 2 g/L of amino acids ( casein hydrolysate ) exhibited the highest per plant yield, total and marketable fruit yield, significantly excelled on all other interaction treatments.
Genetic variance Components were significant for all studied traits except for total leaf chlorophyll content and the percentage of dry matter in the foliage. Environmental variance values were also significant for all traits. Broad-sense heritability was high for plant height, number of fruits per plant, per plant yield, total fruit yield, and marketable fruit yield. For fruit traits, a high heritability estimate indicates that the phenotypic performance of an individual is largely determined by its genetic constitution. This implies the potential for direct improvement of these traits through selection in subsequent growing seasons. The expected genetic advance, expressed as a percentage of the trait mean, ranged from low for total leaf chlorophyll content, foliage dry matter percentage, number of days to the appearance of the first female flower, and sex ratio, to moderate for the remaining traits.

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