Genetic variability and association of characters in some potato (Solanum tuberosum L.) Genetypes in jimma zone, southwest Ethiopia

Abstract

Potato is one of the most important tuber crops for food, feed and industrial applications worldwide. However, not enaph numbers of improved varieties are available due to lack of adequate characterization, evaluation and genetic analysis works. Therefore twenty five potato genotypes were tested in a simple lattice design at jimma Zone (Southwest Ethiopia) with the aim of studying the extent of genetic variation and association among yield and related traits. Analysis of variance indicated significant difference among the 13 trait with respect to all the characters except four traits among the tested genotypes studied. Wide range of variation was observed among all traits. The phenotypic coefficients of variation values were higher than genotypic coefficients of variation values. Higher heritability coupled with higher genetic advance as per cent of the mean were noticed for weight of tuber yield per hectare, date of flowering, plant height tuber diameter and leaf width. This indicates that there is an opportunity of selection to improve these characters. The Mahalanobis’s D2 analysis showed that the 25 genotypes were clustered into five clusters. Maximum inter-cluster distance was recorded between clusters IV and V followed by clusters III and V clusters II and IV and cluster I and II. In majority of the cases, the genotypic correlation coefficients were higher than corresponding phenotypic correlation coefficients.Weight of tuber per hectare was positively and significantly correlated with total tuber per plant and marketable tuber per plant at genotypic as well as phenotypic level. As per path analysis, the maximum positive direct effect on tuber yield per hectare was exhibited by average tuber number, followed by days to flowering could be considered as selection criteria in potato breeding program. The result of the present investigation may vary with season since this study was conducted in one season. That means the available genotypes should be further studied for more seasons over many locations. Furthermore, the presence of morphological variation between genotypes is not a guarantee for high genetic variation. Hence, molecular or biochemical studies need to be considered as complementary to this study.