Correlation analysis of effective traits and their assessment on big tuber yield in potato

In order to find the superior genotypes and high yielding potato varieties, the experiment was carried out on 33 introduced potato genotypes and varieties based on a complete randomized block design with four replications, in which a number of morphological characteristics were investigated. Results of analysis of variance on the recorded traits revealed that the studied genotypes were significantly different based on the studied characteristics. Regarding the importance of big size potato tubers and its effects on the potato total yield, the yield correlated characteristics were studied by path analysis on phenotypic and genotypic correlations, for their positive and negative direct and indirect effects. Among the studied characters, thirteen characters showed high correlations either to the big size tuber or to the other yield components, which were used in the path analysis. The most phenotypic direct effects on the big size tuber yield were imposed by total tuber weight per plant, number of main stems per plant and plant dry weight. Several traits such as fresh total plant weight and date of maturity showed high negative direct effects on big size potato tuber weight. The majority of the studied characters affected the increment of big size tuber yield through their indirect effects. The most genotypic positive and negative direct effects were imposed on big size tuber yield by total tuber weight per plant, tuber length, maturity date, fresh plant weight, number of medium and small tubers, respectively. Indirect effects of the studied characteristics showed more effective influence on big tuber yield rather than direct effects.