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Submitted to: International Plant Germplasm Resource Institute
Publication Type: Book / Chapter Publication Acceptance Date: 8/13/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Germplasm collections are maintained for all major crop species. These collections are typically large, and it is difficult to evaluate the entire collections for specific traits. Core collections are representative sample of germplasm collections. They typically are about 1/10th the size of entire collections and should serve as an indicator for the genetic diversity present in the entire collection. This is a review paper that summarizes all research that has been conducted to select, utilize, and evaluate a core collection for the U. S. germplasm collection of peanut. A core collection has been selected for the U.S. germplasm collection of peanut using standard techniques. A major benefit of having a peanut core collection has been a great increase in peanut germplasm evaluation work. Work by several groups of researchers has resulted in the evaluation of core accessions for 24 characteristics and the identification of numerous sources of resistance to several economically significant pests and pathogens. Data for resistance to late leaf spot and the peanut root-knot nematode were used to evaluate the effectiveness of a two-stage core screening approach in identifying resistance to the entire collection. Both studies demonstrated that the core collection approach can be used to improve the efficiency of germplasm evaluations. Technical Abstract: The U. S. germplasm collection of peanut (Arachis hypogaea L.) consists of over 7,000 accessions and contains a great amount of genetic diversity. However, this diversity has not been adequately evaluated or extensively used in cultivar development. A core collection for the A. hypogaea germplasm collection was developed to attempt to enhance the utilization of fthe entire collection. The U.S. germplasm collection was first stratified by country of origin and then divided into nine sets based on the amount of additional information available for accessions and on the number of accessions per country of origin. Seventy percent of this core collection was selected by stratifying by country of origin before using multivariate analysis on morphological data to cluster accessions into groups and then randomly sampling 10% from each group. Because of the lack of morphological data for some accessions, 29% of this core collection was selected using a 10% random sample after stratifying by country of origin. The remaining 1% was a simple random sample. A major benefit of having a peanut core collection has been a great increase in peanut germplasm evaluation work. Work by several groups of researchers has resulted in the evaluation of core accessions for 24 characteristics. This has resulted in the identification of numerous sources of resistance to several economically significant pathogens. Data for resistance to late leaf spot and the peanut root-knot nematode were used to evaluate the effectiveness of a two-stage core screening approach in identifying resistance to the entire collection. Both studies clearly demonstrated that the core collection approach can be used to improve the efficiency of germplasm evaluations. |
