Associations among Yield and Yield-related Characters in Potato (Solanum tuberosum L.)

Abstract

Twenty potato (Solanum tuberosum L.) genotypes were tested at Ankober (3100 masl), Ethiopia, during the 2002 main rainy season to estimate the nature  and magnitude of correlations and path coefficient analysis among eleven characters. The experiment was laid out in RCB design with three replications  on a plot size of 6.75 m². Highly significant differences (P < 0.01) were observed among the genotypes for all the characters studied. The result of the  experiment indicated that though genotypic correlations were higher in magnitude than that of phenotypic correlations, the direction of phenotypic  correlation coefficients were the same as that of corresponding genotypic ones for majority of the characters. At genotypic level, tuber yield per plant  was positively and significantly (P < 0.01) correlated with stem number per hill (rg = 0.588) and leaf area per plant (rg = 0.759). Path coefficient analysis at  genotypic level also indicated that these characters had positive indirect effects on tuber yield via tuber number per plant. This result suggested the  possibility of simultaneous selection of stem number per hill and leaf area per plant with tuber number per plant to maximize tuber yield. Path coefficient  analysis at genotypic level further indicated that average tuber weight, tuber number per plant, above ground biomass and internode  number are important components of tuber yield per plant. Positive and high magnitude direct effect of average tuber weight and tuber number per  plant, and their relatively high negative indirect effects on tuber yield per plant via each other indicated the need to be cautious during simultaneous  selection for improving tuber yield per plant.