Performance of Six Generations on Two Rice Crosses under Submergence Stress and Non-stress Conditions

Submergence tolerance has long been regarded as an important breeding objective for rain-fed lowland and deep water rice area. Despite this recognition, there has been limited success in developing rice with improved submergence tolerance in Africa. The present research was aimed at assessing performance of crosses under submergence stressed and non-stressed conditions in Nigeria. Six generations of the crosses were evaluated under optimum and submerged conditions in a complete randomized block design with three replications. Submergence screening was performed in controlled conditions that allowed flooding at a water depth of 1.0 meter for a period of 14 days. The results revealed that significant difference among the generations of the two crosses evaluated. The observed survival rate (%) in Cross I of the generations ranged between 0.00% - 100% while in Cross II, it ranged between 0.00% and 95.24%. The Phenotypic Coefficients of Variation (PCV) and the Genotypic Coefficient of Variation (GCV) for 100 grain weight were moderate to high under the two conditions. Low to moderate PCV and GCV coefficients of variation were observed for the grain width and grain length under both conditions in the two crosses. High heritability (0.96% respectively) and high genetic advance as percentage of mean were recorded for the grain yield and grain weight in the two crosses. The variability observed among the generations was optimum however, advancement of the segregating generations coupled with adequate selection criteria could lead to identification of superior and stable genotypes for farmers’ use.