Abstract:
Greenhouse experiment is carried out to explore the outcome of γ-radiation on physiological and genetic variation in red radish (Raphanus sativus) for two generations. Gamma rays from 60Co were used to penetrate red radish seeds with different dose levels (0.0, 10, 20, 40 and 80 Gy). Plants generated from irradiated seeds and from self-pollination of these plants, called M1 and M2 generations, respectively. Some morphological and physiological traits were then determined, and the genetic diversity of both generations was studied using Start Codon Targeted (SCoT) and Conserved DNA-Derived Polymorphism (CDDP) molecular markers. All studied morphological traits (number of leaves/plants, leave height, root diameter, and root weight) were steadily improved by raising irradiation dose rate, reaching a cumulative raise at the irradiation doe level 40 Gy and decreased at dose level 80 Gy. Photosynthetic pigments of red radish plants released a notable increase by increasing gamma rays dose level for chlorophyll (a), chlorophyll (b) and carotenoids for 40 Gy dose rate. Proline content was elevated proportionally to the irradiation dose level, with the greatest increase seen at dose level of 80 Gy. Moreover, phytochemical screening was detected for the both two generations. Fourteen SCoT primers generated a total number of banding patterns of 194 with average 13.86 and the primer SCoT-33 released the highest number banding patterns (21). The percentage mean of polymorphism for all the SCoT primers was 74.66% and was 66.49 and 63.74% for M1 and M2 respectively. Furthermore, fifteen CDDP primers generated a total number of banding patterns of 186 and the primer CDDP-5 relieved the highestnumber of banding patterns (20). The percentage mean of polymorphism for all the CDDP primers was 73.41% and was 64.38 and 65.91% for M1 and M2 respectively. It could be concluded that gamma irradiation exhibited an appropriate variation in red radish M1 and M2 which was detected by SCoT and CDDP molecular markers
