Tropentag, October 11 - 13, 2005 in Stuttgart-Hohenheim "The Global Food & Product Chain – Dynamics, Innovations, Conflicts, Strategies"

Surveying and Collecting Native Centrosema, Stylosanthes, and Desmodium Germplasm in Venezuela

¹Central University of Venezuela (UCV), Agricultural Botany, Agricultural Ecology, Venezuela
²University of Hohenheim, Biodiversity and Land Rehabilitation in the Tropics and Subtropics, Germany
³National Institute of Agricultural Research (INIA), CENIAP-Maracay, Venezuela
⁴National Institute of Agricultural Research (INIA), CIAE-Monagas, Venezuela
⁵National Institute of Agricultural Research (INIA), CIAE-Anzoátegui, Venezuela

Abstract

Venezuela is considered as one of the countries with the greatest biodiversity in the world. Such attribute is explained by the variety of topographic, climatic and edaphic conditions. Consequently, the country comprises a large number of different natural environments such as high mountains, arid and semiarid regions, tropical forests, wetlands and savannahs, and 22 different life zones and more than 600 vegetation types have been identified. As a result, the existing flora is very rich, with a high diversity of native legumes. Exploration and surveying of Venezuelan native legumes, specifically Centrosema, Stylosanthes, and Desmodium, were carried out between 2000 and 2002 as a collaborative project among several national institutions. Fifteen intensive exploration and collecting trips of varying duration were carried out during the dry months of that period. These missions covered eight states in areas such as the central and eastern llanos, and the foothills and mountain zones south of the “Cordillera de la Costa”. A total of 152 seed samples, 79 herbarium specimens, 50 soil samples and three of root nodules were collected. The germplasm included eight, seven and five identified species of Centrosema, Stylosanthes, and Desmodium, respectively. The former genus was the most collected, with a total of 91 seed samples representing 60% of the total collection, followed by Stylosanthes with 33 samples (22%), and Desmodium with 26 (17%). Within each genus, the most collected species were C. molle, S. hamata and D. tortuosum, with 46, 6 and 5 samples, respectively. Maps with the geographical distribution of the entire collection, as well as a preliminary classification of a 34-accession collection of C. molle by climatic groups, using the GIS software FLORAMAP™, are presented. The resulting groups within the C. molle collection are based on differences in total rainfall and its annual distribution, as well as the altitude and temperature of the collecting sites. Possible associations between natural distribution, climate, soil texture and fertility, and habitat of origin are discussed. The actual germplasm collection has been the basement for the creation of the national seed-bank of forage plants.

Keywords: Centrosema, Stylosanthes, Desmodium, legume collection, natural distribution, plant genetic resources (PGR)

Contact Address: Orlando Guenni, Central University of Venezuela (UCV), Agricultural Botany, Agricultural Ecology, University Avenue, 2101 Maracay, Venezuela, e-mail: oguennihotmail.com