A survey on correlation and path coefficient analysis between yield and yield components of cultivars and early advanced average potato clones in spring cultivation of Ardebil region

For the aim of correlation among traits and its analysis to cause and effect relation in potato plant, in crop year of 2012 in Ardebil agriculture and natural resources research center an experiment was carried out on 12 early advanced average potato clones with three check varieties including: Agria, Marfona and Satina. The experimental design was randomized complete blocks with 3 replications. In the statistical analysis of this research 15 significant traits were studied. The results of variance analysis indicated that excluding traits of tuber number less than 35, tuber weight less than 35 and tuber weight more than 55 between clones and cultivars, all analyzed traits had a significant difference at 1% and 5 % levels of probability. This suggests a high genetic diversity between clones and cultivars in the selection for experimental traits. Correlation coefficient showed a significant and positive relation with traits of plant height, stem diameter, number of tuber per plant, tuber weight between 33 – 35 and tuber weight per plant. Tuber yield had the highest correlation (0.959) with tuber weight per plant among these traits. Multiple regression analysis through tuber yield step method showed that the first applied variable in the model was tuber weight per plant that justified 0.919 of changes merely by itself. The second variable was the number of tuber per plant that altered the coefficient to 0.946 along with plant height. The third variable was plant height that changed coefficient model to 0.965 and ultimately as stem diameter was applied coefficient model reached 0.969. Path analysis of the remaining traits in regression model suggested that tuber weight per plant had the most direct effect with tuber yield (1.032) and after that average plant height had direct and positive effect with tuber yield (0.368) in addition number of tuber per plant and stem diameter per plant had direct and negative effect on tuber yield. In conclusion the most crucial traits as selection criteria for tuber yield improvement including tuber weight per plant and plant height respectively were identified.