Abstract

African yam bean (AYB) (Sphenostylis stenocarpa (Hochst ex. Rich) Harms) is an important food in most tropical African countries where it is consumed as either dry cooked seeds or as tuber. Seed quality properties play a major role in genetic improvement and conservation of AYB, if it will contribute to national food security, and prevention of the looming food crisis. The genetic variability in seeds of some African Yam Beans accessions were selected from southwestern Nigeria, and were estimated by studying the physiological quality, traits using germination test, accelerated ageing test and conducting test. Cluster analysis was conducted on similarity estimates using single linkage method (nearest neighbor). Application of cluster analysis resulted in a dendogram representing the genetic relationship among the accessions. A wide genetic variation was observed among the accessions in seed quality traits such as hundred seed weight, germination percentage, accelerated ageing germination percentage as well as bulk conductivity readings. Overall, standard germination percentage was 60.53±27.56%, while standard germination index was 5.74±0.74%, accelerated ageing germination was 28.65±16.81 days and bulk conductivity recorded 62.24±36.25 µScm^-1g^-1. These results indicate high level of significance (p<0.01) for variability especially in viability and vigor of the tested seeds. African yam beans accessions were classified into 4 subgroups with hundred seed weight, germination percentage and seedling quality traits contributing significantly to the grouping underlying the broad genetic base of the accessions. Results showed a high genetic variability among the AYB accessions such genetic variability is useful in facilitating the development of a large number of new genotypes through hybridization by transfer of useful genes, thus maximizing the use of such available genetic potentials in boasting food production for sustainable food security.

Key words: Accession, genetic variability, Sphenostylis stenocarpa, cluster group.