GENETIC VARIABILITY FOR YIELD, YIELD RELATED TRAITS AND MALTING QUALITY OF ETHIOPIAN SORGHUM [Sorghum bicolor (L.) Moench] GENOTYPES

Abstract

Sorghum is drought tolerant C4 tropical crop with wide diversity grown for food, feed and beverages. There is a growing demand for food and malt type sorghum varieties due to the low supply of mat barley, climate resilient and gluten free nature of the crop. Therefore, this study was initiated to characterize the malting quality, genetic variability, heritability, associations among traits and the relative importance of traits in influencing grain yield and malting quality of sorghum genotypes. The experiment was conducted at Fachagama in Mhoni ARC, Northern Ethiopia in 2016/17 in α- lattice design in two replications using supplementary irrigation. Data were collected on agronomic traits, and selected 300g pure seeds were malted (18hr steeping, 72hr in 28 oc germinated and 24hr in 50 oc dried) for malt quality analysis. The analysis of variance revealed that significant differences among the genotypes for all traits including GY, FHWE, DP and MWL ranged 2350-7164.22 kg ha -1, 53.2%-76.8%, 11.36 - 98.07 °WK and 13.47-22.66%, respectively. The genotypes Baji, Tseada Achire, Abare-1, Yeju, Dabar, Degalit yelow-1 and Degalit Yellow were producing better malt quality; considering the most important malt quality parameters of DP, FHWE, CP, ET and MWL. Higher genotypic coefficient of variation was observed for PH , NPT, GY, and DP and medium for DF,DM, TKW, KW, KT, and MWL with low magnitude difference to PCV suggesting low environmental influence. High heritability ranging 85.00-98.99 was observed for all the traits, except for PH (77.83) and CP (61.42) which was moderate. The medium to high GCV, moderate to high heritability and high GAM (20.89-128.43 ) of DF, DM, PH, NPT, GY, TKW,KW, KT, MWL and DP indicating these traits were controlled by additive genetic factors and are important for sorghum yield and malt quality improvement. Positive and significant correlation with grain yield of TKW (0.766, 0.715), KL (0.671, 0.644), KW (0.524, 0.491) HLW (0.532, 0.504, FHWE (0.257, 0.241) and DP (0.275, 0.271) at both phenotypic and genotypic level respectively was recorded. Based on its highest positive significant correlation TKW exerted high positive genotypic (0.334) and phenotypic (0.287) direct effect and higher indirect effect on grain yield indicated that attention should be given for this trait primarily for direct and indirect selection. Thousand kernel weight and fine grind hot water extract showed considerable positive direct effect and significant positive correlation with diastatic power at genotypic level and increment in these traits results in advancement of DP. The first five PCA explained 72.7% of the total variation and the traits NPT (0.75), CP (0.645), DP (0.601), MWL (0.582), DF (0.445), DM (0.433) and HLW (0.412) accounted for most of the variability. Four clusters were found and significant distance were observed among all inter clusters. Thus wide genetic divergence may favor the use of these genotypes in breeding to improve yield and malt quality of sorghum. However, as this study was done in one location for few genotypes and limited malting conditions; the study should be repeated across more locations, optimizing the malting conditions especially in different germination hours are imperative for further exploitation of the diverse sorghum genotypes