EVALUATION OF A CORE COLLECTION TO IDENTIFY RESISTANCE TO LATE LEAFSPOT PEANUT

Core collections have many potential uses and could greatly increase t he 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 the n randomly sampling 10% from each cluster, During the period 1986 to 1 991, held studies were conducted to screen the entire collection for r esistance to late leafspot [Phaeoisariopsis personata (Berk. & M.A. Cu rtis) Arx syn. Cercosporidium personatum (Berk. & M.A. Curtis)]. The p urpose of this study was to use information on leafspot resistance for the entire collection to test the core collection concept in peanut, Disease ratings fur the core collection accession(s) within each clust er were defined as the indicator value for that cluster. Data were exa mined to determine how many leafspot-resistant accessions would have b eer. identified by examining the core collection and all accessions fr om clusters having a resistant indicator value. The use of this two-st age screening approach with the peanut core collection would have resu lted in the identification of 61 leafspot resistant accessions, This a pproach would have required screening 27% of the entire collection and would have identified 54% of the resistant accessions in the entire c ollection. This approach would have resulted in the identification of the best four and eight of the best 10 sources of resistance in the en tire collection. These results demonstrate that this core collection c an be used to improve the efficiency of peanut germplasm evaluations.