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United States Department of Agriculture

Agricultural Research Service

Research Project: SUNFLOWER GERMPLASM DIVERSIFICATION AND CHARACTERIZATION UTILIZING WILD SUNFLOWER SPECIES, CYTOGENETICS, AND APPLIED GENOMICS

Location: Sunflower Research

Title: Ecological characterization of wild Helianthus annuus and H. petiolaris germplasm in Argentina

Authors
item Poverene, Monica - NAT'L. UNIV. ARGENTINA
item Cantamutto, Miguel - NAT'L. UNIV. ARGENTINA
item Seiler, Gerald

Submitted to: Plant Genetic Resources: Characterization and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 30, 2008
Publication Date: July 14, 2008
Citation: Poverene, M., Cantamutto, M., Seiler, G.J. 2008. Ecological Characterization of Wild Helianthus annuus and Helianthus petiolaris Germplasm in Argentina. Plant Genetic Resources: Characterization and Utilization. 7(1):42-49.

Interpretive Summary: Wild annual sunflower and prairie sunflowers are species native to North America where the former is widely distributed and the latter is restricted to the central region of the U.S. These species have become naturalized in central Argentina distributed over an area of about 12 million acres. Since their establishment 60 years ago they have continuously increased in area, behaving as an invasive species providing evidence that they will continue to spread. Both species are valuable germplasm resources for cultivated sunflower. No studies have been done to determine the ecological parameters for the Argentine populations. Eighteen ecological regions in Argentina were survey for wild sunflower species and their associated species. The associated plant communities were comprised of 60 species belonging to 16 families, all being frequent components of the native flora. Disease symptoms were seldom observed in wild populations, with Alternaria helianthi being the most commonly observed pathogen. Population size varied from less than 100 to more than 100,000 plants, covering from 100 to more than 60,000 square meters with densities most frequently up to three plants per square meter, but reaching 80 plants per square meter at certain sites. Intermediate plant phenotypes between wild species and cultivated sunflower were found in one-third of the populations providing evidence of intense gene flow. Hybrid swarms were found at three localities with population sizes between 100 and 10,000 individuals. The naturalized species in Argentina constitute a potential germplasm reservoir of biotic and abiotic traits for sunflower crop improvement.

Technical Abstract: Helianthus annuus and H. petiolaris (Asteraceae) are wild sunflowers native to North America but have become naturalized in central Argentina covering an area of about 5 million hectares. Wild H. annuus has been recognized as invader species in several countries, but no research has been done to study the ecological determinants of their distribution. In a survey covering seven provinces between 31º58'-38º S and 60º33'-69º W, we described the ecology of the main wild populations. Wild Helianthus populations were located in three of the 18 ecological regions of Argentina, on five Mollisol and seven Entisol soil groups. The associated plant communities were comprised of 60 species belonging to 16 families, all being frequent components of the native flora. Disease symptoms were seldom observed in wild populations, with Alternaria helianthi being the most commonly observed pathogen. Population size varied from less than 100 to more than 100,000 plants, covering from 100 to more than 60,000 square meters with densities most frequently up to 3 plants per square meter, but reaching 80 plants per square meter at certain sites. Intermediate plant phenotypes between wild species and cultivated sunflower were found in one-third of the populations providing evidence of intense gene flow. Hybrid swarms were found at three localities with population sizes between 100 and 10,000 individuals.

Last Modified: 9/10/2014
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