Responses of Selected Lowland Rice (Oryza Sativa Linnaeus.) Genotypes to Environmental Stress in Badeggi, Niger State, Nigeria

Abstract

Rice (Oryza sativa Linnaeus.) production in Nigeria is constrained by abiotic stresses including drought, salinity, and iron toxicity. This study evaluated 30 lowland rice genotypes for tolerance to these stresses using phenotypic, physiological, and agronomic parameters. Drought screening was conducted under field conditions with irrigation withdrawal, while salinity (0, 8, 16 dSm?¹) and iron toxicity (0, 150, 300 ppm Fe²?) were evaluated in screen house experiments. Results revealed significant genotypic variability (p<0.05) for all traits assessed. Under drought stress, FARO 68 exhibited the highest grain yield (1,227.26 kg/ha) and stress tolerance index (STI=2.10), while FARO 34 was most susceptible. Salinity screening identified FARO 44 and FARO 68 as highly tolerant with lowest salt injury scores (1.00-2.33) and maintained grain yields of 25.03-31.17g at 16 dSm?¹. For iron toxicity, Alh Baba, FARO 33, and FARO 44 showed strong tolerance with injury scores ≤1.67 at 300ppm. Correlation analysis identified panicle length and 1000-grain weight as key yield determinants under stress. High heritability (0.77-0.98) and genetic advance estimates for yield traits suggested additive gene action. FARO 16 demonstrated combined tolerance to all three stresses, showing low yield reduction (0.40%) under drought, salinity tolerance at 8 and 16 dSm?¹, and iron toxicity score of 1.00 at 150ppm. These tolerant genotypes represent valuable genetic resources for breeding programs targeting stress-prone environments in Nigeria.