Genetic improvement for grain yield under drought stress, composition and gene action on elite sorghum Genotypes of Kenya

Abstract

World food security is greatly challenged by climate change effect. Sub Saharan Africa is adversely affected by drought with considerable yield losses. The solution to food insecurity in these areas depends on the breeding of crop genotypes with improved adaptation for yield, drought and nutrition. Thus, the study was undertaken to; a) investigate the performance of elite sorghum varieties for yield under moisture stress b) to evaluate the nutritional composition of International Centre for Research in Semi-Arid Tropics (ICRISAT) sorghum genotypes and, c) to assess the gene action for grain yield among the crosses generated between Kenya Agricultural and Livestock Organization (KALRO) and ICRISAT genotypes. The elite genotypes from KALRO were evaluated for grain yield under drought stress for three seasons at KALRO- Kiboko Substation during the 2014/2015 short and long rains. For nutrition analyses, grains from ten genotypes derived from ICRISAT were evaluated for nutritional composition at the University of Nairobi food science department. The data sets were subjected to analyses of variances (ANOVA). Results showed that two KALRO genotypes namely Red Swazi and Wheatland reported greater yield and two ICRISAT genotypes namely IESV23006DL and IESV23010DL scored highly in terms of total proteins and total phenols. The two selections from KALRO were then crossed to two selections from ICRISAT to generate population which combines both yield, drought tolerance and nutritionally rich genotypes using North Carolina mating design 11 (NCD11). The F1 generations were advanced to F2. Agronomic data was obtained from ten middle row plants randomly selected and subjected to ANOVA and mean squares obtained used to determine the combining ability of the traits. Analysis of variance revealed significant differences in plant height, panicle yield and days to 50% anthesis among the genotypes. These sorghum progenies are promising in ensuring food security and positively meet the challenges of malnutrition and lifestyle diseases affecting human health in view of climate change effects experienced in the semi-arid areas of Kenya. Key words: Drought, nutritional composition, gene action