Assesment of morphological variations in M4 mutants of IR 841 Rice (Oryza sativa L.) induced by Gamma irradiation

In response to the ongoing decline in the productivity of rice varieties cultivated in Togo, the major challenge is to select highly productive varieties adapted to the diverse agroecological conditions of the country. To address this, the present study explored gamma radiation-induced mutagenesis techniques on the IR841 rice variety to create potential genetic diversity, which is essential for varietal improvement and selection. The objective of this work was to determine the existence of morphological variability, indicative of genetic diversity, among the induced mutant lines of the irradiated variety. A total of 50 induced mutant lines of the IR841 rice variety, as well as two controls, the non-irradiated IR841 variety and the NERICA_L14 variety, were evaluated. The experimental design was a completely randomized block design with three replicates. A total of 18 descriptors (5 qualitative and 13 quantitative), were used. The results revealed significant phenotypic variability both within the evaluated mutant lines and between these lines and the controls. Qualitative traits such as panicle exsertion, leaf color, and plant architecture highly significantly varied. Approximately 70% of the mutant lines presented good panicle exsertion. The leaf coloration diversity ranged primarily from intermediate green to deep green. The quantitative traits also varied considerably, including plant height (44 to 106 cm), tiller number (18 to 156), and days to 50% flowering (68 to 115 days). These traits enabled the grouping of the 50 studied mutant lines into 4 clusters. These results demonstrate morphological variability, and thus potential genetic diversity, among the evaluated mutant lines.