Genetic Diversity among Selected Nigerian Rice (Oryza sativa L.) Cultivars for Agronomic Improvement Towards Sustainable Food Security

Abstract

Rice (Oryza sativa L.) is an important cereal crop that serves as a staple food for millions of people in Nigeria and more than 50% of the world's population. Therefore, with the changing climate and global food challenges, the need to identify potential rice (Oryza sativa L.) cultivars cannot be overemphasised. Hence, the study seeks to explore and measure the level of genetic diversity among selected rice germplasm resources in Nigeria, to identify potential candidates for rice improvement programs. The experimental layout was a complete randomized block design (CRBD) with three replicates per cultivar. Genetic diversity was assessed using 10 SSR markers on 40 Nigerian rice cultivars. The study revealed significant variability among evaluated cultivars. Cluster analysis of molecular data divided the 40 cultivars into two major clusters with subclusters. Molecular analysis revealed 3.8 average alleles, heterozygosity (He = 0.55), gene diversity (GD = 0.58), Shannon’s index (I = 0.49) and PIC of 0.51 among rice cultivars, indicating a moderate level of genetic diversity. Heritability was highest in grain yield (H² = 0.97). The observed polymorphism suggests potential cultivars with ample opportunity for a crop improvement program to develop new, resilient, high-yielding climate-smart cultivars through breeding.