America and the Far East including China, Japan, Korea, and Taiwan. He realized that plant diversity was not distributed equally around the world, but was focused in specific regions. His theoretical concept of the centers of origin for cultivated plants
Eggplant (Solanum melongena L.) was introduced by the Arabs into Spain. Since then, many local cultivars have arisen. These materials are grouped in four cultivar groups: “round,” “semi-long,” “long,” and “listada de Gandía.” We studied the morphological and molecular [amplified fragment length polymorphism (AFLP)] diversity of a collection of 28 Spanish traditional cultivars of eggplant. Four eggplant accessions from different origins were used as controls and three scarlet eggplant (Solanum aethiopicum L.) accessions as outgroups. Morphology and AFLP markers showed that S. melongena and S. aethiopicum are separate taxonomic entities, and that, compared to controls, Spanish eggplants are very variable, indicating that the Iberian Peninsula can be regarded as a secondary center of diversity. Morphological differences were found among cultivar groups in traits other than those used for the grouping although, in some cases, accessions from different cultivar groups shared a similar general morphology. Eggplant cultivar groups also showed some genetic differences, which are revealed in the gene diversity statistics (GST = 0.30). Nonetheless, no individual AFLP markers specific and universal to one cultivar group could be found. “Round” cultivars were genetically more diverse than the other cultivar groups. A positive correlation (r = 0.68) was found between morphological and molecular distances. However, correlations between geographical and either morphological or molecular distances were low. Results suggest that evolution of eggplants in Spain has involved frequent hybridizations and a frequent movement and exchange of seeds. Structure of diversity among regions indicates that most of the diversity can be collected in single selected regions. All these results have important implications in eggplant germplasm conservation and breeding.
Significant effort has been made in the collection of Capsicum germplasm throughout the world for maintenance by genebanks. The largest Capsicum germplasm collection is held by the Asian Vegetable Research and Development Center (AVRDC), consisting of 6844 accessions and eight species. The paradox of any germplasm collection is that, as the number of accessions and the probability of preserving genetic variability increases, the ability of users to efficiently utilize this resource decreases. Genetic variation can be quantified using RAPD molecular marker allele frequency and allelic variation to understand the genetic structure and variation within and among populations. The comprehensive Capsicum collection held at the AVRDC provides an opportunity to sample a range of germplasm representative of the variability that exists in available Capsicum germplasm. Accessions were sampled from the AVRDC collection to represent the range of genetic variation available in Capsicum 1) based on cluster analysis using morphological traits among 1500 accessions and 2) based on pedigree information from the Capsicum breeding program. Our objectives include understanding the structure and magnitude of genetic diversity among these AVRDC accessions and comparing the genetic diversity within sub-populations of these accessions. RAPD fingerprints of these accessions were collected using markers dispersed over numerous linkage groups based on a genetic map we have constructed. RAPD band frequencies and RAPD band diversity were used to test differences among and within sub-populations. The understanding of the distribution of genetic variation among and within these sub-populations will be useful for prioritizing collection, conservation, and sampling of these genetic resources.
The East African region in sub-Saharan Africa (SSA) is widely considered as one of the secondary centers of diversity for sweetpotatoes [Ipomoea batatas (L.) Lam.]. Farmers in the region typically grow landraces, but hybridizations occasionally result in new genotypes. Factors such as regional conflicts, natural disasters, disease, and land pressure continually threaten the SSA sweetpotato gene pool. Despite this threat, very little updated information is easily accessible about SSA germplasm collections. Such information is valuable for purposes of management, exploration, and conservation. Using germplasm collection data from Kenya, Tanzania, and Uganda, we demonstrate how publicly available GIS-based tools, e.g., DIVA-GIS, can be used to document current collections as well as make this information easily accessible, searchable, and portable. First, collection data from each country were compiled and known collection sites were georeferenced using available gazetteers. Following data cleaning and verification, georeferenced data were then converted into a GIS-compliant format, primarily as shapefiles. All files were then copied into storage media for exchange among stakeholders. To further demonstrate the portability of the GIS database files, available World Wide Web GIS web viewers enabled real-time access to GIS files uploaded to an experimental web site. This work demonstrates that with very little expense, access to extant SSA germplasm information for sweetpotatoes can be improved using publicly available GIS tools.
1 To whom reprint requests should be addressed; email: sch10@cornell.edu . We thank Frank Dennis, Ned Garvey, James Hancock, Jules Janick, and Stephen Krebs for their prompt and thoughtful reviews of this
centers of origin (diversity) for cultivated crop plants ( Vavilov, 1992 ), and the concept of genetic erosion, have directed present-day global plant science, breeding, and conservation efforts ( Hummer and Hancock, 2015 ). He realized not only that wild
authors, wild-type melon originated from south and east Africa ( Mallick and Masui, 1986 ). However, recent work suggests that melon originated in Asia ( Sebastian et al., 2010 ). This idea is supported by the fact that the primary center of diversity of
International, 2007 ). These areas include centers of diversity for several crop plants and their wild relatives: apple, pear, pistachio, apricot (secondary center), onion, garlic, spinach, carrot, wheat, peas, lentils, chickpea, and flax ( Zohary, 1970 ). PEO
Vegetable Center in Taiwan. Primary centers of diversity for cultivated tomato are Chile, Ecuador, Peru, and Mexico, with secondary centers throughout the world (Villand et al., 1998). Breeding of cultivated tomato has emphasized crosses with wild
., 2009 ; Albrecht et al., 2011 ) and this has been used to identify putative centers of diversity and domestication events. However, it is difficult to determine the wild forms of C. chinense as clearly as in the other domesticates ( Eshbaugh, 1993