Botanical and agronomic evaluation of a collection of Sesbania sesban and related perennial species

The species Sesbania sesban has many attributes which make it attractive as a multi purpose tree for different agricultural production systems. This thesis focuses on the evaluation and classification of a S.sesban collection on morphological, agronomic and nutritional characteristics. It provides information on the chromosome numbers, breeding system and interspecific relations of S.sesban and the related perennial species S.goetzei and S.keniensis. It also demonstrates the multi disciplinary research approach which is required for the development of multi purpose tree germplasm.The three species have a chromosome number of 2n = 12 and are able to produce viable seeds after interspecific hybridization. They are both self and cross compatible, although outbreeding is thought to be the common method of reproduction under natural conditions. The classification shows that the S.sesban accessions in the collection contain large variation in morphological, agronomic and nutritional characteristics. Through numeric analysis it is possible to identify distinct groups of accessions within the collection. This group structure can be used for the selection of accessions low in polyphenolics and with a high agronomic productivity.The species is at the moment relatively underutilized and there seems to be scope for a greater use of it, particularly in alley farming or for improved fallow. S.sesban has definite potential for the highlands and could further be introduced to the higher rainfall areas of the semi-arid zone and in some subhumid areas. It could be very useful to reclaim some of the areas with saline and alkaline soils and could also be grown in places prone to seasonal waterlogging and flooding.The areas which require future research attention are among others, the collection of germplasm, the identification of anti- nutritional factors and the further adjustment of the management techniques to the systems in which the species is being used.