Phytogeography of the genus Sesamum l (pedaliaceae) in Nigeria, West Tropical Africa

The geographical distribution patterns of Sesamum L species occurring in Nigeria was studied with a view to providing information on their locations within the country for ease of access during need for them. Nigeria was divided into six (6) zones (A-F) for ease of reference and coverage. For thirty six months (36) months, trips were undertaken to various zones as divided for collection of samples. Visual assessments were also made and notes taken on areas of collection. Eight (8) herbaria were also visited with the aim of collecting information on areas of collection by collectors and determinavits. On the whole, a total of forty(40) specimens were examined. The results indicated that S. alatum occurred in the much drier regions of the area of the study and was therefore regarded as being xerophytic. The other three species, S. indicum, S.radiatum and S. angutifolium were thickly populated and occurred more in the middle belt zone (E) of the study area where the amount of rainfall is not too high, though S. indicum appeared to be ubiquitous in its occurrence. The species were observed to be adapted to specific ecological zones of the country. The study revealed also that S. alatum fresh specimen was difficult to come by indicating a form of threat and therefore requires conservation. The information generated on distributional pattern could separate the species under investigation into two groups; S. alatum on one side and the other three on another. The detailed information on distribution study of Sesamum species in Nigeria is available for the first time. The implication of the findings in this study to ease of access, agronomic, scientific and medicinal plant research is discussed. Efforts should be geared towards the protection of the wild species for genetic improvement of the highly cultivated S. indicum.

کلیدواژه ها:

SesamumAgronomicXerophyticConservationGeographicalDistributionPattern