Molecular ecology and population genetics of two multipurpose tropical trees, Moringa oleifera lam and M. stenopetala ( Back. F) cuf

Abstract

M oleifera Lam.and M stenopetala (Bale. f) Cuf are multipurpose tropical tree species native to India and East African lowlands respectively. In tropical developing countries, both species provide a variety of useful products such as coagulants for water clarification, edible oil, vegetable, fodder, traditional medicine and use in agroforestry systems. M oleifera was introduced to Kenya about 100 years ago, but until recently, the species was considered of marginal value and details on these introductions, the genetic diversity and relationships within and among the introduced populations have not been documented. In addition, information on genetic structure in M stenopetala and its relationship with M oleifera and their potential for improvement is currently lacking. RAPDs and AFLPs were used in genetic analyses in M oleifera (chapter 3) and in order to further understand the resulting genetic structure and relationships, work was carried out to investigate clonality (chapter 4) and estimate outcrossing rates (chapter 5). To gain insights into agromorphological relationships, their variability and potential for improvement, and M oleifera provenance trial was established in Kenya (chapter'6). The genetic structure inM stenopetala populations was investigated using RAPDs and AFLP markers and the relationship between the two species determined using AFLP (chapter 7). Data revealed hierarchical genetic structure, extensive sexual reproduction, self-compatibility, reduced genetic variation and possible multiple origins among Kenyan M oleifera provenances. Most of the phenotypic variation in quantitative traits among Kenyan M. oleifera was found within provenances. A wide divergence and different genetic structures in both species was found. The importance of data for the conservation, utilisation, management and improvement of genetic resources within both species are discussed.