Ultraviolet radiation affected on cellular components indirectly via oxidative mechanisms involving the formation of free radicals. Therefore, this study aimed to investigate morphological and physiological alterations in two varieties and their six hybrids of summer squash. Hybrids were extracted from hybridization between irradiated and nonirradiated plants via a half diallel crosses design. The genotype obtained from hybridization between P₂ × M₁~P₂ promoted the number of leaves per plant if compared with nonirradiated parents. Meanwhile, the genotypes extracted from hybridization between P₁×M₁~P₁, P₁× M₁~P₂ and P₂×  M₁~P₁promoted the leaf area per plant. However, total chlorophyll in fruits was decreased in the genotypes affected by UV‑irradiation than the parental wild types. Extracted hybrid from hybridization between    P₂×  M₁~P₁recorded minimum days (46.33) to start the first packings of fruits. Meanwhile, the extracted hybrid from hybridization betweenP₁× M₁~P₂ produced the highest number of fruits per plant, fruits weight per plant and average weight of fruit, all of which determined fruits yield per plant.