Stability Analysis of Coffee (<i>Coffea arabica</i> L.) Bean Yield Using GGE Biplot in South Western Ethiopia

Abstract

Coffee is the largest export crop, and the backbone of the Ethiopian economy. The experiment were conducted at Metu, Gore and Chora for two consecutive years with the objective of determining the nature and magnitude of genotype x environment interaction, to classify environment based on genotype performance and identifying stable genotypes on coffee yield by using GGE biplot analysis. A total 17 advanced coffee genotypes were laid out using randomized complete block design with three replications. The analysis of variance for coffee bean yield revealed the presence of highly significant difference (P<0.01) among genotypes, environments and genotype by environment interaction. Results of GGE biplot showed that the first two principal components (PC1 and PC2) justified 65.66% of the sum of squares with PC1=49.12% and PC2=16.54% of the GGE sum of squares. The six test environments were divided into four different coffee growing mega-environments. Among the test location Metu2 and Gore2 were the most representative and most discriminating environment while Chora2 was less powerful to discriminate genotypes or less desirable as a testing location for coffee bean yield. Genotype G5 (236/71), followed by G8 (872/74) and G12 (227/71) were stable and high yielder across coffee growing environments and it recommended for mega environment production.