حمیدرضا نوریزدان

ABSTRACT  The history of Sunflower domestication and especially the selection of high seed oil content explain several bottlenecks that reduced the genetic diversity of the crop compared to the wild relatives. The underlying genetic control of a crop's interaction with its environment is complex and often poorly understood. Studies of geographic and climatic variation can provide important information regarding patterns of adaptation to different habitats and ecological isolation. The objective of the present study was to determine the patterns of distribution of morphological variation for thirteen quantitative characters in 77 accessions of wild sunflower evaluated in the same site.  The collection of genetic resources of wild H. annuus, as held at the French National Institute for Agricultural Research (INRA) in Montpellier, includes approximately 350 populations, which have been collected in the USA. Seventy – seven wild sunflower accessions from this collection were compared in France (Mauguio) for 13 quantitative characters using multivariate methods, including clustering, principal component and canonical discriminate analysis to assess the patterns of morphological and climatic variation. Geographic and climatic data from their sampled sites were analyzed and we sought for correlations of climatic variables and morphological traits. Populations from northern Mexico and southern Canada were not available at that time. Ward's hierarchical clustering (Ward, 1963) was used to identify groups of climatic sites and of morphology forms. Hierarchical clustering was applied by SAS software (SAS, 2000). Principal Component Analysis (PCA) (PRINCOMP procedure, SAS software) was performed on the correlation matrix of the morphologic and climatic variables bases on the mean accession value. Canonical discriminate analysis (CDA) on the basis of climatic clustering was used to assess the differences between morphological variations of the 77 accessions for the thirteen ch