Correlation and path coefficient studies for selecting traits contribution to root yield in Sweetpotato genotypes (Ipomoea batatas (L.) Lam)

This study was undertaken to determine associations among yield and yield related traits in sweetpotato crop so as to identify the major traits of importance that could be used as a basis for soil nutrients formulation. The experiment was conducted at Umudike in rain forest region during 2013 and 2014 cropping season. The experiments were laid out in split randomized complete block designs with three replications. The plot size used was 3m x 2m with 1m inter and intra- row spacing. The treatments included eight sweetpotato genotypes and combination of Fertilizer treatment NPK 15:15:15 and Poultry manure. Observations were made on the following characters: number of Salable root, Length of salable root, width of salable root, fresh salable root, Dry matter content, vine length at 4 week after planting, number of Leaves at 4 week after planting, vine length at 4week after planting, and Vine diameter at 4 weeks after planting. Data collected were analyzed using analysis of variance and means were separated using Standard Error of difference. Correlation and path analysis were used to select and determine characters that contributed significantly to root yield of sweetpoitato. The result of correlation and Path analysis revealed that number of salable roots, width of salable roots, number of lateral branches at 4 weeks after planting (WAP), vine length at 4WAP, number of leaves at 4WAP and dry matter content were characters that exhibited high direct effects on root yield per plant. Improving these characters through soil amendment at the recommended levels of nutrients would give better response of these characters to root yield improvement in sweetpotato.