Evaluation of the core collection approach for identifying resistance to Meloidogyne arenaria in peanut
2000
Holbrook, C.C. | Timper, P. | Xue, H.Q.
Core collections are representative subsamples of germplasm collections. Use of core collections may improve the efficiency of germplasm evaluations by reducing the number of accessions evaluated while increasing the probability of finding genes of interest. 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 with 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.
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