Trait Association and Path Coefficient Analyses in Cassava

Abstract

Cassava (Manihot esculenta Crantz.) is one of the most widely grown tropical root crops. Tuber yield is a complex quantitative character controlled by several genes, and its improvement depends on the functioning and interaction of several components that vary for different genotypes. A study was conducted to investigate associations among traits and their direct and indirect influences on yield using path analysis and correlation procedures in cassava genotypes to understand how intercharacter relationships influence tuber yield. Genotypes were characterized based on response of qualitative and quantitative characters. Correlation and path coefficient analyses were carried out for characters of yield and its components. Differences were observed among genotypes. Character association indicated that tuber yield·per hectare was positively and significantly associated with petiole length, number of leaves per plant, total leaf area, stem diameter, tuber diameter, plant dry matter content, starch content, and hydrogen cyanide (HCN) content. Path analysis indicated that number of leaves per plant, stem diameter, number of tubers per plant, tuber diameter, and plant dry matter content exerted a high positive, direct effect on tuber yield per plant; the remaining characters had negligible to low indirect effects through other component characters. The high direct effect of these traits appeared to be the main factor for their strong association with tuber yield·per hectare.