Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2010
Publication Date: 11/1/2010
Publication URL: http://hdl.handle.net/10113/46754
Citation: Oliveira, M.F., Nelson, R.L., Geraldi, I.O., Cruz, C.D., Toledo, J.F. 2010. Establishing a soybean germplasm core collection. Field Crops Research. 119:277-289. Interpretive Summary: Germplasm collections are the assemblage of the natural variation that exists for a crop or potential crop and the relatives of these species. These collection provide the raw material for plant breeding and genetic research. Germplasm collections for major crops, such as soybean, can be very large. This can make it prohibitively expensive and/or very time consuming to evaluate all entries for some economically important characteristics. A core collection is a representative sample of a large collection that can contain much of the diveristy of the entire collection in approximately 10% of entries. Core collections can be used as the first entries to be evaluted when looking for new traits. In this research, we used 5 different sampling procedures to select a core collection of the soybean entries in the USDA Soybean Germplasm Collection. Selection was based on origin of the germplasm and data collected on 28 traits. The best sampling procedure identified a core collection that maintained 93 to 100% of variability of 18 quantitative traits evaluated in the entire collection. This included such traits as plant height, seed yield, seed size, and seed oil and protein composition. The list of soybean accessions included in the core collection is available through the Germplasm Resources Information Network website at http://www.ars-grin.gov/npgs/. The core collection will be of value to all scientists that use soybean germplasm in their research.
Technical Abstract: Core collections are of strategic importance as they allow the use of a small part of a germplasm collection that is representative of the total collection. The objective of this study was to develop a soybean core collection of the USDA Soybean Germplasm Collection by comparing the results of random, proportional, logarithmic, proportional multivariate and logarithmic multivariate sampling strategies. All but the random sampling strategy used stratification of the entire collection based on passport data and maturity group classification. The proportional multivariate and logarithmic multivariate strategies made further use of qualitative and quantitative trait data to select diverse accessions within each stratum. The 18 quantitative trait data distribution parameters were calculated for each core and for the entire collection for pairwise comparison to validate the sampling strategies. All strategies were adequate for assembling a core collection. The random core collection best represented the entire collection in statistical terms. Proportional and logarithmic strategies did not maximize statistical representation but were better in selecting maximum variability. Proportional multivariate and logarithmic multivariate strategies produced the best core collections as measured by maximum variability conservation. The soybean core collection was established using the proportional multivariate selection strategy. The list of soybean accessions included in the core collection is available through the Germplasm Resources Information Network website at http://www.ars-grin.gov/npgs/.