Variation, correlation and path coefficient analyses in seed yield and related characters in local accessions of African Yam Bean (Sphenostylis stenocarpa) from Southern Nigeria

Local accessions of African Yam Bean, a poorly studied and under-utilized but important food crop, from Abia, Akwa Ibom and Cross River states of Southern Nigeria were studied for variation in seed yield and pod characteristics. Correlations were carried out on the studied characters to determine the degree of mutual association among them while path coefficient analysis was used to partition the correlation coefficients into their direct and indirect effects on seed yield. Results revealed that significant differences (p<0.01) exist among the accessions with respect to the studied characters. Mean number of seeds per pod ranged from 13.27 to 18.87; seed weight per pod from 3.19 to 6.21g; weight of 100 seeds from 22.86 to 36.72g; pod length from 21.67 to 36.82 cm and pod width ranged from 0.79 to 1.05 cm. Number of seeds per pod and pod length had significant positive association with seed weight per pod. Pod width also correlated positively with seed weight in some accessions. Positive direct effects on seed weight per pod were obtained with number of seeds per pod and pod length. The results taken together revealed significant variations in the accessions and provide evidence for effective selection which is a prerequisite for genetic improvement.   Key words: Sphenostylis stenocarpa, accessions, variation, correlation, path coefficient analysis.