DROUGHT AND IRON TOXICITY TOLERANCE OF LOWLAND RICE (ORYZA SATIVA L.) GENOTYPES IN NIGERIA

Abstract

This study evaluated thirty lowland rice genotypes for tolerance to drought and iron toxicity under controlled and field conditions at National Cereals Research Institute, Badeggi, Nigeria. A randomized complete block design was used for drought screening. The two experiments: Drought stressed and non-stressed experiments were laid side by side, separated by high bond. The size of the experimental field was 30 x 15 m², gross plot size was 2 x 1 m² with 66 plant population per gross plot and 6 stands per net plot, while iron toxicity was assessed using graded Fe² concentrations (0, 150, and 300 ppm). Significant genotypic variation (P < 0.05) was observed for drought response traits including leaf rolling, tip burn, and recovery indices. Genotypes; FARO 15, FARO 44, FARO 57, FARO 68, and FARO 52 demonstrated a superior drought tolerance based on recovery and low stress scores. Iron toxicity screening revealed variability in tolerance, with tolerant genotypes exhibiting reduced leaf bronzing and sustained growth under high Fe² conditions. The findings highlight the potential of selected genotypes as candidates for breeding programs targeting combined stress tolerance in lowland rice-ecosystems.