Abstract:
A field experiment was conducted under submergence conditions to evaluate Oryza glaberrima genotypes flash flooding stress. The experiments were conducted in the research field of the Africa Rice Center. The first experiment was conducted in the dry season of 2013. Two-thousand and fifty O. glaberrima accessions screened for submergence tolerance in an augumented design with 2 repeated checks (SWARNA SUB1 and FARO52). From these, twenty (20) genotypes were selected based on percentage survival after submergence. These were subjected to further evaluation in two experiments in wet and dry season of 2014 and 2015. The experiments were laid out in Randomized Complete Block Design with three replications Data were collected on survival percentage, days to 50% flowering, plant height, tiller number, panicle number, plot yield, gall midge incidence, 1000 grain weight and lodging and subjected to Analysis of variance (ANOVA), from which the estimates of variance component, broad sense heritability, correlation analysis and Rank Summation Index (RSI) were generated.
The rice genotypes differed significantly within and across seasons for survival percentage, days to 50% flowering, plant height, tiller number, panicle number, plot yield, gall midge incidence, 1000 grain weight and lodging. TOS6454, TOS6447 and TOS6455 had the best mean performance for all the traits evaluated across the seasons. TOS6454 recorded the highest yield and mean survival percentage under flash flooding compared to the tolerant check (SWARNA SUB1) while VIAH had the least survival percentage. The highest mean plant height was recorded in UG28 while the highest yield was recorded in TOS6454. The Genotypic coefficient of variation (GCV) was lower that the phenotypic coefficient of variation in all the traits studied indicating influence of the season on the expression of the characters. The high estimates of heritability recorded in all the traits suggest that a wide scope of improvement in the
