Estimates of genetic parameters and genotype by environment interactions for sugar yield and its components in sugarcane genotypes in Western Kenya

Abstract

This study was conducted to estimate broad sense heritability, genetic advance, GE interactions and correlations among quality traits in sugarcane clones in western Kenya. Thirteen sugarcane promising clones and one check cultivar were evaluated plant and ratoon crops in three locations under rain fed conditions using the randomised complete block design with three replications.  Analysis of variance showed significant differences in hand refractometer brix, sucrose content (Pol% cane), juice purity, fire content, sugar yield and brix yield. Sucrose content, fibre content, sugar yield and brix yield exhibited significant genotype × location (GL) interactions. The genotype mean squares exceeded the GE interactions for all the quality traits suggesting that more emphasis should be placed on testing clones in many locations than on testing ratoon crops within locations. High genetic coefficient of variation (GCV) was detected for cane yield (8.12%), brix yield (6.39%), sugar yield (5.69%) and sucrose content (3.69%). Broad sense heritability was high for sucrose content (0.712) and moderate for cane yield (0.515), fibre content (0.474), juice purity (0.445) and refractometer brix (0.380). Cane yield (10.3%), brix yield (6.7%), sucrose content (5.5%) and sugar yield (5.4%) showed highest expected genetic advance.  The results indicated that these traits may respond positively to selection and present opportunities for improvement through breeding. High genetic correlation (rg=0.998) between refractometer brix and sucrose content suggest that selection for refractometer brix can be effective in identifying varieties with high sucrose content. Key words: Saccharum spp. heritability, genetic advance, sucrose content, selection, sugar.