Abstract

A field study was conducted in derived savannah ecology to evaluate sixteen upland rice genotypes comprising breeding lines, recent releases and established cultivars for the effect of different rainfall-seasons on genotypic trait expression and to identify those harbouring drought adaptive characters. Plantings were done in the early and late rain seasons of 2006 and 2007, respectively. Data were collected on root, vegetative and reproductive traits and analyzed using the analysis of variance (ANOVA) and simple correlation. The genotypes revealed some variability for root, shoot, and grain yield characters which can be exploited to improve drought tolerance and grain production. There were significant variety, season and variety-by-season effect for most of the root, vegetative and reproductive characters. IRAT 170 had relatively better root volume and dry weight making it a suitable parent for upgrading drought tolerance in new rice for Africa (NERICA) 1, ITA 150, WAB 56-50 and genotypes with superior grain production. Reproductive and vegetative characters were positively correlated with most root characters, suggesting possibility of joint inheritance. Root thickness notably was not correlated with other root and shoot characters. Continuous introgression of drought adaptive traits into promising genotypes for tolerance to variable soil moisture, typical of derived savannah ecologies, was canvassed.

Key words: Drought, rice, interspecific hybrids, derived savannah ecology, grain yield.

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