Assessment of radio-sensitivity for three bambara groundnut [vigna subterranea (l.) verdcourt] varieties to gamma-ray irradiation in Burkina Faso

Bambara groundnut [Vigna subterranea (L.) Verdcourt] is a highly nutritious food legume. However, the low genetic variability of Bambara groundnut is a limitation to its improvement to address various biotic and abiotic constraints. Gamma-irradiation mutagenesis is one of the techniques to create genetic variation in order to select new varieties to meet users' needs. However, the effectiveness of such method depends on identifying the appropriate radiation dose for each variety. This study aimed to determine the optimal lethal doses of mutagens producing maximum mutations with minimum damage. Seeds of three Bambara groundnut varieties (KVS115, KVS234 and KVS259) were subjected to five gamma-ray irradiation doses (200, 250, 300, 350 and 400 Gray). The radiation source was Cobalt-60, with an irradiation rate of 28.81 Gray/min. Irradiated and non-irradiated (control) seeds were sown in the field at INERA Saria station using a complete block design. Data were collected on parameters relating to seed germination, plant survival and pod yield of the varieties. A linear regression model was developed to determine the mean lethal dose (LD) and reduction dose (RD) of both varieties. The results revealed a decrease in germination and survival rates and a drop in pod weight with increasing irradiation doses. The KVS259 variety recorded 100% lethality at the 250 Gray dose and was the most sensitive to gamma irradiation. Variety KVS115 was the least sensitive to gamma irradiation, with 75% lethality at the highest dose of 400 Gray. Optimal doses varied between 148 Gray and 363 Gray depending on the variety. These results could be used in mutagenesis breeding programs to select mutants with desirable agronomic and nutritional traits for farmers and consumers.