生物多様性、生物探査および開発のジャーナル

Identification and Distribution of Wild Yam in North Rift, South Nyanza and Western Regions of Kenya

Abstract

Joseph Rotich Chemwetich, Emily Jepkosgei Too , and Onkware Augustino Osoro

Yams (Dioscorea spp.), especially the non-domesticated wild types, are orphan food resources in Kenya. There is minimal documentation on wild yam diversity in Kenya, despite the fact that they are harvested for a variety of uses, and are threatened with rapid disappearance due to habitat loss. To contribute to their conservation and preserve indigenous knowledge for potential development of new cultivars and future research, the identity and diversity of wild yams in some parts of Kenya was investigated. Sixty (60) wild yam accessions from thirteen (13) surveyed, selected and georeferenced localities including Kombosang (KB1), Moigutwo (MB1), Kasaka (KB2), Mormorio (MB2a and MB2b), Kapkwang (KB3a, KB3b and KB3as) and Katimok Forest (KB4a and KB4b), Kolol (KEa, KEb and KEc), Turesia (TE, TEs1 and TEs2), Kapseret Forest (KUa, KUb and KUc), Chepsangor (CN1a), Chepkomiat (CN2a and CN2b), Nyakomisaro Stream (NK) and Lugusi (LKa) were collected, dried and identified using taxonomic available keys/information. The identities of twelve (12) yam-like accessions from Katimok Forest (KB4c*), Chepsangor (CN1b*), Chepkomiat (CN2c*) and Lugusi (LKb*) were also determined. A questionnaire was employed to collect data on indigenous knowledge and the proportion of the locals who could identify and name wild yam was calculated. The distribution of wild yams in North Rift, South Nyanza and Western regions of Kenya, was described. The sixty wild yam accessions belonged to three species, thus: Dioscorea schimperiana Kunth. (KB1, MB1, MB2, KB3a, KE1, TE, KUa, CNa, NK and LKa), Dioscorea bulbifera L. (KB4a, KEc and KUb) and Dioscorea quartiniana A. Rich. (KB2, MB2b, KB3b, KEb, KUc and CN2b). Accessions KB3as and TEs1 were considered Dioscorea schimperiana Kunth.sub-species 1 while TEs2 was considered as sub-species 2. On the average, only smaller proportions (below 40%) of respondents in all the localities could identify and give the local name of the wild yams. Dioscorea schimperiana Kunth was widespread in North Rift, South Nyanza and Western Kenya while D. quartiniana and D. bulbifera were limited to North Rift. This study is the first to contribute to classification of wild yams found in Kenya. The results show that diverse wild yam species exist in various geographical locations in Kenya, but only a few members of local communities are knowledgeable about these wild yams.