Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2005
Publication Date: 7/1/2005
Citation: Holbrook Jr, C.C., and W. Dong. 2005. Development and evaluation of a mini-core collection for the U.S. peanut germplasm collection. Crop Sci. 45:1540-1544. Interpretive Summary: The United States maintains an extensive collection of peanut germplasm that was collected from throughout the World. This collection consists of almost 9000 accessions. Because of its size, it is difficult to examine the entire collection to identify traits that could be of value for the U.S. peanut industry. Core collections are representative subsamples that can be used to improve the efficiency of germplasm evaluation. A core collection has been selected for the U.S. peanut germplasm collection. This has stimulated a great amount of germplasm evaluation work and has resulted in the identification of numerous sources of resistance to several economically significant pathogens. However, an even smaller subset of germplasm is needed for traits that are difficult and/or expensive to measure. Through this research we developed a mini-core collection and showed that it can be used to improve the efficiency of identifying desirable traits in peanut germplasm.
Technical Abstract: A core collection (831 accessions) has been developed to represent the U.S. Arachis hypogaea germplasm collection. This core collection has been shown to be effective in improving the efficiency of identifying genes of interest in the entire germplasm collection. However, an even smaller subset of germplasm is needed for traits which are difficult and/or expensive to measure. The objectives of this study were to select a mini-core of the core collection and to evaluate the usefulness of this subset of germplasm to identify genes of interest in peanut. Data for eight above ground and eight below ground morphological characteristics were measured for each accession in the core collection. Cluster analysis was used on these data to partition the core accessions into groups which, theoretically, are genetically similar. Random sampling was then used to select a ten percent sample from each group. The result was a mini-core of the core collection consisting of 111 accessions. Examination of morphological data indicated that the majority of genetic variation expressed in the mini-core collection has been preserved in this core of the core collection. Data on disease resistances for accessions in the core collection were collected and used to retrospectively determine how effective the use of a mini-core of the core collection would have been in identifying sources of resistance in the core collection. Results indicated that the mini-core can be used to improve the efficiency of identifying desirable traits in the core collection. For resistance to leaf spot, the use of this mini-core would have improved the efficiency of identifying resistant accessions in the entire collection. The mini-core approach should be particularly useful for traits which are difficult and/or expensive to measure.