Phenotypic diversity in wild Helianthus annuus from Argentina

PRESOTTO, ALEJANDRO; CANTAMUTTO, MIGUEL; POVERENE, MÓNICA; SEILER, GERALD

HELIA

Institute of Field and Vegetable Crops, University of Novi Sad

Año: 2009 vol. 32 p. 37 - 50

1018-1806

Wild Helianthus annuus populations naturalized in central Argentina have spread since their introduction from the center of origin in North America. Phenotypic characterization based on 45 morphological and phenological descriptors of nine populations from different geographic regions of Argentina and 17 populations from the USA provided by the US Department of Agriculture germplasm bank at Ames, Iowa was obtained by growing populations in an experimental field. Wild populations from Argentina reflected part of the phenotypic variability of populations from the center of origin, but showed adaptation to local conditions which allow differentiation between populations from each continent. All traits showed a continuous range with the majority of extreme values in populations from North America. The populations that showed similarities for one group of descriptors differed by other traits, revealing the existence of different phenotypes. Helianthus annuus populations established in Argentina could be considered a differentiated genetic resource, containing new combinations and traits absent in North American populations, such as life cycle length in the Diamante population of 180 days and longer, the longest of any population studied.