Diversity among Stylosanthes species: Habitat, edaphic and agro-climatic affinities leading to cultivar development.

ABSTRACT

Since the introduction of Stylosanthes, a range legume, in India in early seventies extensive efforts have been made for its evaluation and adaptation. However, limited germplasm and narrow genetic base were major impediments in its wider adaptations. Of late, introduction of several new improved germplasm including newly identified species, cultivars and bred materials from Australia, Colombia, Brazil and Ethiopia and their evaluation at selected centers under different agro-climatic conditions improved the existing scenario as many lines including S. scabra RRR as well as newly introduced species S. seabrana has shown great promise for diverse agro-climatic zones. Because of concerted efforts which was largely generated from the recently concluded Austrialian Centre for International Agricultural Research (ACIAR) stylo project and background study during the period of early eighties Stylosanthes has been considered as the most important tropical legume which not only improve the soil fertility but also provide nutritive forage. Two species namely S. hamata and S. scabra largely contribute to the supply of forages for cattle, buffalo, goats and sheep. As a nitrogen fixing legume, the plant helps replenish soil nutrients when used in ley farming, mixed and inter-cropping systems. The scenario has largely changed due to the better performance of newly introduced S. seabrana species which possessed high seedling vigour, high nutritional parameters and better adaptation under rainfed situations in heavy clay and cracking soil types. It provides good foliage and being erect and low sticky in nature showed compatibility for mixed cropping. Results also demonstrated reasonable yield in first year by all four major species which ultimately geared up in second year of growth. This was stable in S. hamata and S. viscosa for another two years whereas other two species namely S. scabra and S. seabrana indicated enhanced yield in consecutive years.