Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 7, 1999
Publication Date: N/A
Interpretive Summary: The U.S. germplasm collection of peanut contains over 7,000 different peanuts selected from throughout the world. This collection contains many valuable genes for traits like disease resistance. Once identified, these genes will be very useful in the development of new U.S. peanut varieties. Screening a germplasm collection for these useful genes is an enormous task. A more efficient method of identifying these genes is needed. We have selected a core collection for the U.S. germplasm collection of peanut. This is a representative subsample of the entire collection. In theory, screening of this subsample (831 types of peanuts) will provide a road map for where to go in the entire collection to find more useful genes. We tested this theory by screening the core collection for resistance to the peanut root-knot nematode. Screening the core collection indicated 30 groups within the entire collection that should be examined. When we examined these groups we found that they contained a significantly higher percentage of peanuts that contained resistance. These results demonstrated that a core collection approach can be used to improve the efficiency of identifying valuable genes in germplasm collections.
Technical Abstract: Core collections are representative subsamples of germplasm collections. Use of core collections may improve the efficiency of germplasm evaluations. The peanut (Arachis hypogaea L.) core collection has been examined for resistance to the peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1]. Resistant indicator accessions from screening the core collection identified 39 clusters in the entire germplasm collection that should be examined more thoroughly. The objective of this study was to evaluate how effective a two-stage core screening approach would be in identifying resistance to M. arenaria in the entire U.S. germplasm collection of peanut. Accessions from 30 clusters having resistant indicator accessions and from four clusters having very susceptible indicator accessions were tested for resistance in two greenhouse trials. This second stage screening identified 259 accessions that had a mean egg-mass rating of 2.5 or less. Twenty-eight of these accessions had a mean egg-mass rating of 1.0 or less. There were relatively large numbers of resistant accessions from China and Japan compared to the percentages of the germplasm collection that originated from these countries. The efficiency of identifying accessions resistant to M. arenaria was greater in clusters having resistant indicator accessions than in clusters having susceptible indicator accessions. These results demonstrate that the use of a two stage screening approach with a core collection can improve the efficiency of identifying valuable genes in germplasm collections.