GENOTYPE x ENVIRONMENT x MANAGEMENT INTERACTION OF COMMON BEAN (Phaseolus vulgaris L.) ON ACIDIC SOILS OF WESTERN ETHIOPIA

Abstract

Common bean is one of the most important cash crops and protein sources for smallholder farmers in many low lands and mid altitude areas of western Ethiopia. Its production is mainly constrained by soil acidity problem. Furthermore, in the past it has been known that bean varieties are highly sensitive to soil acidity and differential interaction of varieties with the environment, while soil acidity management practices have also been practiced. Thus, the present study was aimed to examine the effect of genotype x environment x management interaction on seed yield and yield related traits in common bean and to determine the stability of the genotypes across environment and managements. Fifteen common bean genotypes were tested in 2016 cropping season at four acidic prone areas of western Ethiopia namely Nedjo, Mandi, Bambasi and Assosa using split plot design with lime treated and untreated as main factors and the genotypes as sub-factors. Data collected from each location were analyzed both for individual location as well as across locations. The result revealed that there were significant (p<0.05) difference among genotypes, environment, management and genotypes by environment interaction for days to flowering, pod per plant, biomass yield and seed yield. There were also significant (p<0.05) differences among genotypes, environment, and management for days to maturity, seed per plant, and total number of nodules, which showed that genotypes performed differently to diverse environments and the environment had different discriminating power. Moreover, genotype by environment by management interaction had significant effect on yield which shows that the genotypes performed differently across environment upon the application of lime. AMMI stability model was used to identify stable genotype and genotypes with specific and wider adaptation. Accordingly, genotype ALB 207, BFS 39 and ALB 179 had higher yield and wider adaptation, while genotypes BFS 35 and ALB 212 had high mean yield but specific adaptation. Based on four stability models such as Lins and Bins cultivar superiority, Wricks’ecovalence, Nassar and Huehn’s mean absolute rank difference and variance of ranks and AMMI stability value; genotype ALB 179 was found to be stable both on lime treated and untreated soil and ALB 209 was stable genotype on lime treated soil while BFS 39 on lime untreated soils. AMMI - biplot showed that Assosa was most discriminating environment while Mandi was the most favorable environment for the tested bean genotypes. Specific best performing genotypes were; at Assosa (ALB 163); Nedjo (ALB 209) and at Bambasi (BFS 24). Generally, genotypes ALB 207 and BFS 39 have performed best at Mandi, and this two can also be recommended for all the four testing sites and other areas with similar agro-ecology without lime application, while genotypes ALB 133, ALB 204 and BFS 39 for lime treated soils because of their wider adaptability.