Effects of gamma irradiation on agromorphological characteristics of chili (Capsicum annuum L.) var. Kulai

Abstract

The increasing demand for chilli has drawn the interest of chilli breeders to improve the production of this crop. Mutation breeding is applied in many crops improvement programs as it can rapidly create the variability of inherited traits in crops. This study evaluates the effects of irradiation doses of radioactive cobalt (60Co) γ rays on seed performances, morphological characteristics and yield of chilli (Capsicum annum L.) var. Kulai grown under laboratory and glasshouse conditions. The chilli seeds were treated with gamma radiation at 0, 20, 40, 60, 80, 100, 200, 300, 400, 500 and 600 Gy. The effect of gamma-rays was assessed towards germination, survival rate and several morphological characteristics. From the observation, seeds from all treatments were germinated (100%) in 10 days. However, the gamma radiation affects the survival rate, fruit length, fruit weight, plant height, and most of the results were lower upon exposure to higher doses particularly 100 Gy and above. Germination rate, plant height, plant survival rate and other morphological characteristics of the irradiated plant were observed to improve at lower doses (40, 60 and 80 Gy). Apparently, lower gamma-ray doses (<100 Gy) were more suitable to study the effect on seed germination as well as other morphological characters of Capsicum annuum L. especially Kulai variety. Mutagenic dose of 300 Gy was estimated as the LD50 for Kulai variety. The findings of this study provide useful information for mutation breeding in Capsicum annuum L. using gamma radiation for future breeding programmes in chilli.