Abstract

Sixteen sorghum varieties were tested in a randomized complete block design with three replications at Sirinka Agricultural Research Center and Kobo sub-center in 2010 with the objectives of estimating the genetic variability, associations among the traits and determining the direct and indirect effect of the traits on grain yield of varieties across the two locations. Analysis of variance revealed that there were statistically significant differences among the varieties for most of the traits across the two locations. From this combined analysis of variance, significant (P=0.01) effect due to location, varieties and GxE was observed for most of the traits. In terms of mean value performance, the varieties showed wider variability in grain yield which ranged from 762.6-2533.3 kg/ha over locations. A relatively high phenotypic coefficient of variation (PCV) values (>20%) were obtained for leaf area index, plant height, panicle weight, panicle yield, grain yield and harvest index across locations. Similarly, high genotypic coefficient of variation (GCV) values (> 20%) were also obtained for leaf area index, plant height, panicle yield, grain yield and harvest index. High heritability estimates (> 80%) were obtained for days to heading, days to flowering, leaf area index, days to maturity, plant height, panicle length and 1000 seed weight. But a relatively high genetic advance was obtained for only leaf area index, plant height, panicle yield, grain yield and harvest index. Grain yield showed significant (P=0.01) positive phenotypic correlations with plant height, panicle weight, panicle yield and harvest index and genotypic correlations with panicle yield. Similarly, significant (P=0.01) positive phenotypic and genotypic correlations between the independent traits was observed. From the path analysis, plant height, panicle weight and harvest index showed high positive phenotypic direct effect on grain yield whereas panicle yield showed negligible positive phenotypic direct effect with considerable indirect effect via panicle weight. At genotypic level, panicle yield showed the highest positive direct effect followed by harvest index and plant height whereas panicle weight showed negative direct effect with high positive indirect effect via panicle yield.

Key words: Genotypic variance, genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability, correlation, direct and indirect effect.