Induction of Genetic Variability in Three Capsicum Annuum L. Cultivars using Gamma Irradiation

Abstract

Micronutrients deficiency affects more than 2 billion individuals globally. Therefore, there is need to improve our plant species to increase their nutritional value, to meet the worlds increasing nutritional insecurity. Induced mutation is one of the methods used in creating genetic variations that could result to new cultivars with different characteristics. Capsicum annum among other qualities is a good source of β-carotene, a precursor of vitamin A. This study was aimed at inducing mutation on three cultivars of Capsicum annuum L. to source for new favourable genetic variations in the M1 generation that could be exploited for better agronomic and nutritional traits. Mutation was induced by exposing seeds of Shombo, Tatase and Nsukka yellow pepper to gamma irradiation with varied dosages (50, 100, 150 and 200 Gy from 60Co source). The evaluation was conducted as a 5 x 3 factorial laid out in a completely randomized design (CRD) in the Botanic Garden of the University of Nigeria. There were significant effects of the mutagenic treatments on most of the parameters evaluated and percentage coefficient of variability revealed a shift in means of the treatments from their controls in both positive and negative directions. The treatment doses showed different morphological effects on the cultivars used. Seeds exposed to 50 Gy induced higher fruits per plants in Shombo (11.2 ± 2.47 fruits) and Tatase (7.00 ± 0.63 fruits) variety while 200 Gy induced higher fruits in Nsukka yellow pepper (10.1 ± 4.39 fruits). Increase in vitamin C, β-carotene, total carotenoid and capsaicin content were observed in fruits of the treated plants as compared to their controls. Shombo fruits from plants irradiated with 50 Gy and 150 Gy recorded significantly the highest β– carotene content with a mean value of 9.71 ± 0.22 mg/ 100 g and 11.35 ± 0.60 mg/ 100 g. Conclusively, there were indications that gamma irradiation dosage of 50 Gy – 200 Gy could be exploited in the creation of variability relevant for the improvement of morphological, yield and biochemical traits in peppers. Irradiation of 50 and 150 Gy dosages could also be exploited in the improvement of pepper for increased β-carotene content.