Development of improved cotton cultivars by induced mutations

Seeds of two superior Greek varieties namely Sindos 80 and 4S were irradiated with gamma-rays (100, 200 and 300 Gy) in order to create new genetic variation and consequently to develop lines resistant to Verticillium wilt. LD50 was found to be around 300 Gy for the two varieties. The treated seeds of both varieties along with the control were sown in 1992. From the two varieties used, 6,000 plants were obtained, some showing morphological differences compared to the control. M2 seeds of 400 plants of M1 generation were sown in small pots and placed in growth chambers. From these M2 seedlings 0.23 - 0.24% in both varieties were albino and about the same percentage were viridis. This gives an indication of the expected mutation frequency for other characters in the same genetic background. (author). 2 refs, 3 tabs