Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/21/2001
Publication Date: 1/1/2003
Citation: WIDRLECHNER, M.P., BURKE, L.A. ANALYSIS OF GERMPLASM DISTRIBUTION PATTERNS FOR COLLECTIONS HELD AT THE NORTH CENTRAL REGIONAL PLANT INTRODUCTION STATION, AMES, IOWA, USA. GENETIC RESOURCES AND CROP EVOLUTION. 2003. V. 50. P. 329-337. Interpretive Summary: Genebank Managers need to understand patterns of demand for their collections in order to set appropriate targets for seed multiplication, packaging, and storage space allocation. But there is little technical guidance on how to analyze demand patterns in support of management decisions. We analyzed germplasm distribution to meet outside requests over a 12-year period for 10 crops conserved by the North Central Regional Plant Introduction Station, to see if distribution rates over given periods of time help predict future demand and to document how distribution patterns vary among samples. We demonstrated that, with appropriate tracking and statistical software, germplasm distribution patterns can be analyzed and plotted over time. Data measured over periods of up to 3 years had little predictive value, while a 6-year period gave relatively accurate projections. Mathematical models, based on between 200 and 700 samples, accurately described distributional rates of 90-95% of all samples. We also discussed how to document changes in usage patterns within and among collections as they mature over time. Our analysis of average shipment size suggested that germplasm demand became more focused over time for 8 of the 10 collections. This can result when researchers request germplasm based on knowledge about specific samples gained through personal experience and by examining evaluation data. Our methods should allow collection managers to conserve their plant germplasm collections more effectively and develop systems that allow them to anticipate future needs.
Technical Abstract: Understanding the patterns of distribution of plant genetic resources may be critical in setting appropriate targets for seed multiplication, packaging, storage space, and other technical operations. We analyzed germplasm distribution patterns over a 12-year period for 10 crop collections conserved by the North Central Regional Plant Introduction Station to determine if distribution rates over a given time help predict future distributions and to document how distribution patterns vary among accessions. We demonstrated that, with an appropriate tracking system and commonly statistical software, germplasm distribution patterns can be easily analyzed and plotted. Data measured over periods of up to 3 years had little predictive value, while a 6 year period gave relatively accurate projections of future distributions. Patterns of distributions within collections varied between those that are approximately normally distributed and those best described by an exponential function, with larger collections tending to be non-normally distributed. Means and standard deviations of standardized, long-term distribution rates, calculated from samples of 200-700 accessions, accurately described the distribution rates of 90 95% of accessions. Analysis of average shipment size suggests that germplasm distributions became more focused over time for 8 of the 10 collections analyzed. This may result when users request germplasm based upon knowledge about specific accessions gained through personal experience and by examining evaluation and characterization data.