Genetic variability and association between agronomic characters in some potato (Solanum tuberosum L.) genotypes in SNNPRS, Ethiopia

Thirteen (13) potato genotypes were evaluated for genetic variability and association of agronomic characters among themselves and tuber yield. The study aimed to find out the genetic variability, and interrelationships among different characters in potato. The plot design used for the experiment was a randomized complete block design with three replications. The analysis of variance showed that the mean square due to genotype were highly significant (p<0.01) for all characters studied, which indicates the existence of sufficient genetic variability and there was less coefficient of variation in all of the characters indicating good precision of the experiment. Genotypic correlation coefficient was found to be higher in magnitude than that of phenotypic correlation coefficients, which clearly indicated the presence of inherent association among various characters. Tuber yield was positively correlated with plant height, biological yield, harvest index and big tuber percentage at both the phenotypic and genotypic levels. In contrast, it was negatively correlated with small and medium tuber percentage at both levels. Path coefficient analysis at the phenotypic level revealed that days to flowering, plant height, tuber diameter, biological yield, harvest index and medium tuber percentage showed positive direct effects on tuber yield. The genotypic path analysis also indicated that biological yield and harvest index showed positive and significant correlation. Therefore, these characters are more important than other traits for the genetic improvement of potato.   Key words: Genetic variability, potato, heritability, correlation, path coefficient analysis.