This study aimed to determine the effect of different gamma irradiation doses on the early growth characteristics of the 5 National Seed Industry Council (NSIC)-registered garlic varieties. Garlic cloves of the varieties, Ilocos Pink, Ilocos White, Ilocos Tan Bolters, Mexican and MMSU Gem, were exposed to different doses (1, 2, 4, 6, 8, 10 and 12 Gy) of gamma irradiation. Non-irradiated garlic served as a control. Both irradiated and non-irradiated garlic cloves were planted in plastic cups under screenhouse conditions. The treatments were arranged in a factorial completely randomized design with 3 replications. Generally, gamma irradiation was observed to have an inhibitory effect on plant height, wherein, as irradiation doses increase, plant height decreases. Regarding leaf length, a decreasing trend was observed as gamma irradiation increased from 1–6 Gy. Higher doses of irradiation (4–8 Gy) had an inhibitory effect on root length, while lower doses were comparable to untreated. Root count increased with gamma irradiation, with the effective dose varying depending on the garlic variety. The results indicate that the optimal gamma irradiation dose is variety-dependent. These results are vital for successful crop improvement works on garlic, as specific doses of irradiation showed phenotypic changes that signify alteration of the genetic make-up of the crop, which needs further study.
Jeremay et al. (Tue,) studied this question.