Phenotypic Variability in Germplasm Collection of African Yam (Dioscorea spp) in North Central Nigeria

Abstract

Yams (Dioscorea spp) are staple food crops of the people in tropical and subtropical region of the world. The crop consists of approximately 600 species. These species are threatened by genetic erosion due to several factors such as pest and diseases attack, inadequate improved varieties and dearth of germplasm collection and conservation. On this premise, this research was carried out to collect and manage the available germplasm in North-Central Nigeria. Fifty accessions of yam (Dioscorea spp) were collected from adaptable farmers’ varieties. These were evaluated according to standard descriptors of yam into four (4) species (D. alata, D. bulbifera, D. dumetorum and D. rotundata). The highest germplasm (21) was recorded in Niger state, which was dominated by white yam (D. rotundata). This was followed by Benue state with twenty (20) accessions. Others are three (3) accesssions each from FCT and Kogi State, then two (2) accessions each from Nasarawa and Kwara States. Of the 50 accessions of yam collected, 40% (20) are rare landraces and are at the brim of becoming extinct locally. Phenotypic observation revealed that tuber skin colour varies from light-brown, through dark and milk spotted to dark and dark-brown. The most dominate of these were dark-brown with 60% of the accessions, this was followed by light-brown and the least were 6% which was recorded for dark-milk spotted accessions. Similarly, tuber shape showed that cylindrical dominated with 80% of the accessions and the least was snake shape with only 4% of the accessions. These findings have given some insights on the available germplasm of yam in North-central Nigeria with promising traits. However, there is for a promising approach of characterisation of the crop species in the area for the improvement, conservation and breeding programme of yam in the future.