Cytogeography and reproduction of the Paspalum simplex polyploid complex |
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| Authors: | M H Urbani C L Quarin F Espinoza M I O Penteado I F Rodrigues |
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| Institution: | (1) Instituto de Botánica del Nordeste, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina, AR;(2) Secretaria de Propriedade Intelectual, Empresa Brasileira de Pesquisa Agropecuaria (EMBRAPA), Brasília, Brazil, BR;(3) Centro Nacional de Pesquisa de Gado de Corte, EMBRAPA, Campo Grande, Brazil, BR |
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| Abstract: | Paspalum simplex is a grass distributed throughout the phytogeographic Chaco region in South America from which sexual diploid and apomictic
tetraploid races have been reported. We analysed native populations to determine their homogeneity of ploidy level, and the
relationship between geographic distribution, ploidy levels, and reproductive systems. The ploidy level was established for
379 plants from 32 wild populations. Tetraploidy and apomixis constitute the most common combination for this species all
over the Chaco region. Apomictic hexaploid plants were found associated with 4x populations. Diploids were confined to a small
sector of the region. One sexual triploid plant arose from seed harvested in a pure 2x population, and one apomictic 3x plant
was found in a mixed 2x-4x population. The results suggest that P. simplex is a core agamic complex characteristic of the Chaco region from which other apomictic polyploid species of the subgenus
Anachyris could have evolved.
Received July 24, 2002; accepted September 12, 2002 Published online: December 11, 2002 |
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| Keywords: | : Paspalum simplex agamic complex apomixis Anachyris phytogeography |
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