Effect of flood stress on growth of selected local rice genotypes

Abstract

Flooding poses a severe threat to global rice production, with Nigeria’s crop yields being particularly vulnerable. This study investigated the impact of flood stress on three local Nigerian rice genotypes—Kwandala, Yar-gafan, and Yar-dass—by evaluating their morphological, biochemical, and genetic responses. Using controlled submergence experiments, morphological traits were measured across vegetative and booting stages. Biochemical assays quantified key antioxidants (ascorbate, glutathione, tocopherol) and oxidative stress markers (malondialdehyde), while genetic screening and phylogenetic analysis were performed to detect the presence of submergence‑tolerance genes SK1 and SK2. Results showed that the genotype of Kwandala exhibited the highest plant height and most favorable antioxidant profile under stress, alongside possessing both SK1 and SK2 genes. In contrast, the other genotypes displayed greater oxidative damage and lacked one or both genes. Overall, Kwandala demonstrated the strongest flood tolerance, attributable to its combined morphological resilience, adaptive antioxidant capacity, and key submergence‑tolerance genes. These findings recommend Kwandala as a promising candidate for breeding programs aimed at enhancing flood resilience in Nigerian rice cultivation.