The present investigation was carried out to study the effects of irradiation by using gamma ray with dose 10 kr on the mean performance and variation as well as the heterosis, potence ratio, inbreeding depression and heritability for the cross between two parents Giza 92 and Giza 93 where either both the parents were treated by irradiation or one parent with addition the cross between two untreated parents was used as control. To obtain the M₁, M₂ and M₃ with addition F₁ and F₂ the trials were conducted during 2015, 2016 and 2017 seasons at Sakha Station. The results indicated that the treatment with irradiation decreased the mean performance for yield and its component traits and increased the variability traits. Moreover the crossing between both treated parent or one treated parent increased variability for yield and its component comparing with the crossing alone. Positive coefficient of skewness were found for seed and lint cotton yield, boll weight and lint percentage while negative coefficient of skewness for fiber quality, moment coefficient of kurtosis were less than 3 for all traits in M₁, M₂ and M₃ for most of populations. The results of skewness curves suggested that Giza 93 irradiation and its crosses had response to selection for seed and lint cotton yield. The effect of irradiation for heterosis, inbreeding depression and heritability for seed and lint cotton yield and lint percentage were higher than the effects of boll weight and quality fiber.