Evaluation of lowland rice (Oryza spp.) varieties for tolerance to flooding in freshwater and estuarine agro ecosystems in Delta State

The study was conducted to evaluate the best 21 identified rice varieties with the flood-tolerant trait in freshwater and estuarine environments. The experiment was a split-plot laid out in a Randomized Complete Block Design (RCBD) with three replications. The varieties by environmental interaction and stability estimate were investigated in four different environments; First Planting Estuarine (FPE)-E1, First Planting Freshwater (FPFW)-E2, Second Planting Estuarine (SPE) -E3 and Second Planting Freshwater (SPFW)-E4. Parameter accessed was Plant height (cm), Number of tillers, and Leaf diameter (cm), Days to 50% flowering, Days to 50% maturity, Number of panicle/plant, Number of grain/panicle, Harvest index, 1000 seed weight (g), Seed yields/plant(g), Seed yield (t/ha). Data collected were subjected to analysis of variance. The result showed that the partitioning of Genotype x Genotype x Environment through GGE biplot analysis showed that principal components I and II accounted for81.7% and 11.8% of GGE sum of squares, respectively, giving a total of 93.5% variation. The AMMI biplot showed a significant difference among varieties at (P<0.05) and Faro 44, Faro 4, Swana Sub 1, Faro 67, Faro 37, and Faro 66, giving the highest mean seed yield (t/ha) of 30.69t/ha, 30.36t/ha, 35.93t/ha, 34.73t/ha, 32.79t/ha and 32.64t/ha respectively in the winning environments E2 and E4. The study concluded Environments E2 and E4 as high yielding and stable and are therefore recommended to farmers for optimum yield.