Molecular analysis of gamma irradiated rice cultivar FARO 44 for submergence tolerance using RAPD markers

Abstract

Rice (Oryza sativa L.) is an essential crop supporting over 60% of the global population, with rainfed lowland and deepwater ecosystems accounting for approximately 33% of global rice cultivation. However, submergence stress caused by seasonal flooding - exacerbated by climate change - significantly threatens rice productivity. This research sought to develop variability in submergence tolerance in FARO 44, a popular Nigerian rice variety, using gamma irradiation. The seeds were given gamma rays at 0, 50, 100, 150, and 200 Gy and submerged entirely for five days at the 21-day seedling level. Plant height and survival rate were some of the measured agro-morphological traits. The highest survival rate (93.75%) was observed at both 150 Gy and 200 Gy doses. To evaluate the genetic diversity within these lines of irradiated rice, molecular characterization was conducted with six primers of Random Amplified Polymorphic DNA (RAPD). The results suggest that 150 Gy and 200 Gy doses had marked increases in survival rates, which indicated improved tolerance. Analysis of the polymorphism showed significant results in the RAPD analysis, where primer B04 had the most considerable polymorphic information content of 0.82 and genetic diversity of 0.84, indicating genetic differentiation and effective change induction. These results confirm that generating rice genotypes tolerant to submergence using gamma irradiation is feasible, while the genetic diversity caused by irradiation can easily be monitored using RAPD markers.