Yield Stability Analysis of Elite Irish Potato ( Solanum tuberosum L.) Varieties in Western Ethiopia

Abstract

Potato is one of the most important horticultural crops widely grown in mid and high lands of Ethiopia. Several potato genotypes has been introduced and tested in different parts of western Ethiopia. However, the stability and performance of these genotypes under different parts of the regions were not yet assessed. Therefore, the objective of this study was to determine the effect of genotype, environment and their interaction for tuber yield and identify stable potato genotypes for possible recommendation. The study was conducted using nine potato genotypes during rainy seasons of 2016 and 2017 at three locations (Gedo, Shambu and Arjo) of western Ethiopia. The experiment was arranged in Randomized complete block design replicated three times. Among the testing locations, high yield (26.56 tha-1) was recorded at Arjo while, low (21.51 tha-1) at Shambu. Similarly, among the tested genotypes CIP39158.30 was showed high yield (36.41 tha-1) followed by CIP384321.30 (35.15 tha-1) while, CIP39264 showed low yield (13.3t/ha). Combined analysis of variance showed the main effect due to environments, genotype and genotype by environment interaction were highly significant (P≤0.01) for tuber yield. The genotype and genotype by environment interaction (GEI) was partitioned using GGE biplot model. The first two principal components obtained by singular value decomposition of the centred data of tuber yield explained 99.75% of the total interaction caused by genotype and genotype by environment interaction (GGE). Out of these variations PC1 and PC2 accounted 77.65% and 22.10%, respectively. Generally, the mean tuber yield, GGE biplot and regression slope identified CIP384321.30 as high yielding and stable genotype in the study area.