Evaluation of a Core Collection to Identify Resistance to Late Leafspot in Peanut

Abstract

Core collections have many potential uses and could greatly increase the utilization of germplasm resources. A core collection was recently selected for the U.S. germplasm collection of peanut (Arachis hypogaea L.) by clustering accessions based on phenotypic similarities and then randomly sampling 10% from each cluster. During the period 1986 to 1991, field studies were conducted to screen the entire collection for resistance to late leafspot [Phaeoisariopsis personata (Berk. & M.A. Curtis) Arx syn. Cercosporidium personatum (Berk. & M.A. Curtis)]. The purpose of this study was to use information on leafspot resistance for the entire collection to test the core collection concept in peanut. Disease ratings for the core collection accession(s) within each cluster were defined as the indicator value for that cluster. Data were examined to determine how many leafspot‐resistant accessions would have been identified by examining the core collection and all accessions from clusters having a resistant indicator value. The use of this two‐stage screening approach with the peanut core collection would have resulted in the identification of 61 leafspot resistant accessions. This approach would have required screening 27% of the entire collection and would have identified 54% of the resistant accessions in the entire collection. This approach would have resulted in the identification of the best four and eight of the best 10 sources of resistance in the entire collection. These results demonstrate that this core collection can be used to improve the efficiency of peanut germplasm evaluations.