Genotype x environment interactions in pigeonpea (cajanus cajan l)millsp grown in seven enviroments of Kenya

Abstract

Ten pigeonpea genotypes Three improved cultivars, four exotic lines and three local farmers pigeonpea genotypes were grown in a randomized complete block design in three replications at five locations for two seasons to study genotype x environment interactions for grain yield and other plant characters. The nature of genotype x environment interactions were investigated by means of regression analysis technique* of Eberhart and Russell [1966] and stability analysis method of Wrickle [1962,1966]. Combined analysis of variance showed that genotypes x environment interaction was significant for grain yield, pods per plant, seeds per pod, 100 seed weight,days to 50% flowering, days to 50% maturity, plant height, length of pod bearing region and number of pod bearing branches. Results showed that a considerable portion of genotype x environment interaction could be attributed to the linear regression for most characters. Pooled deviations from linear regression for most characters were highly significant. There ,were significant differences for all traits except grain yields among genotypes for their regression on environment index. {xvi i} High correlation was found between the ranks of genotypes according to mean performance lx ], regression i 2 coefficient [b J, deviations from regression Is d J i i and Ecovalence [. w j. i The genotypes which were most stable had minimum 2 deviations from regression Ls d j and very small w i i Genotypes showed varied response to the various environments with respect to the various traits. The genotype 423/60 the highest grain yield per plant but lacked stability for this trait. The local farmers varieties were the most desirable cultivars for most traits, followed by the improved cultivars and then came the exotic lines. The response of the localy adapted cultivars to the environments used in this study showed that they were well buffered and could adjust their genotypic and phenotypic states in response to the changing environmental conditions. It was concluded that further experiments with all the genotypes covering more sites and seasons be planned to tap the great potential in these cultivars.