Genotype ­Environment interaction in Potato (Solmrum tuberosum L.)

Abstract

In the present investigation 30 potato genotypes were evaluated for three consecutive years in order to study the extent of variability and to find out the suitable attributes to be used in future potato improvement programme. Seven quantitative characters viz., plant height, number of leaves/plant, fresh weight of plant, number of tubers/plant, number of eyes/tuber, average tuber weight of plant and tuber yield (weight)/plant were used as parameter to estimate heritability, genetic advance, correlation, path coefficients and genetic diversity among the different potato genotypes. Varietal difference and effect of environments on the performance of all the characters were highly significant. Interaction of (gxe/gxy) environments were also highly significant. Genotypic and phenotypic variability were high for number of leaves/plants, fresh weight/plant and tuber weight/plant, but very low for number of tubers/plant and number of eyes/tubers. Heritability (broad sense) and genetic advance were high for fresh weight/plant, number of tubers/plant and tuber weight/plant. Tuber weight/plant showed strong positive genotypic correlation with plant height, number of leaves/plant and fresh weight/plant and a negative correlation with number of eyes/tubers. Path coefficient analysis revealed that fresh weight of plant showed the highest positive direct contribution to tuber yield followed by plant height and number of tubers/plant. Number of eyes/tuber and number of tubers/plants had a high positive indirect effect on tuber yield via fresh weight of plant. Fresh weight of plant appeared to be the important character for getting higher tuber yield in potato. The range of D2 values from 0.368 to 26.394 indicated the presence of possible genetic divergence in the population. Divergence analysis revealed that the 30 genotypes could be grouped into 6 clusters. The highest intra cluster distance was observed in cluster vi (., [" D2 = 0.961) that comprised of 5 genotypes. Intra-cluster distances were zero in cluster I as it had single genotype. The highest inter cluster distance was in between cluster V and VI (✓ D2=26.394) indicated maximum exploitation of heterosis on hybridization breeding technique. Present study elucidates that wide range of genetic variability existed among the thirty potato genotypes that could be used for genetic improvement of potato. Furthermore, among the seven quantitative characters fresh weight of plant appeared to be the important character that could include in the selection breeding of potato for improving tuber yield.