Influence of environment and its interaction effectson new potato [(solanum tuberosum (l.)] mutant lines

Potato (Solanum tuberosum L.) is an important food and income crop in Kenya. Potato growing regions in Kenya are diverse with similar to contrasting environmental conditions. Multi-location trials are necessary when determining agronomic response of new improved lines to environment -genotype interaction. The objective of the study was to determine the yield stability of new improved potato mutant lines under genotype by environment interaction effects. Eight genotypes, consisting of four mutant lines and four commercial varieties were obtained biotechnology seed Unit at the University of Eldoret. The study was carried out in five regions in Eldoret, Burnt Forest, Mosoriot, Marakwet and Nyandarua. The experiment was laid out in a Randomized Complete Block Design (RCBD) in three replications at each site. Data on plant height, days to 50% flowering, stem number, tuber number and tuber weight. Classical ANOVA, AMMI and GGE were used in the analysis of yield stability. The effects of genotype, environment and genotype by environment interaction were significant for all the studied agronomic traits. The analysis revealed IP1 as most stable (widely adapted), IP2 as specifically adapted, IP3 & IP4 showed some stability. The new varieties will reduce the overdependence on Shangi by farmers at the same time giving stable high yields over various geographical regions.