02614naa a2200241 a 450000100080000000500110000800800410001910000200006024501230008026000090020352018780021265000120209065000350210265000310213765000250216865300110219365300220220465300150222670000210224170000250226270000180228777300670230515662342003-02-17       2002    bl ---       0--  u    #d1 aCHAKRABORTY, S.  aPathogenic variation in Colletotrichum gloeosporioides infecting stylosanthes spp. in a center of diversity in Brazil.  c2002  aPathogenic variation in Colletotrichum gloeosporioides infecting species of the tropical pasture legume Stylosanthes at its center of diversity was determined from 296 isolates collected from wild host population and selected germ plasm of S. capitata, S. guianensis, S. scabra, and S. macrocephala in Brazil. A putative host differential set comprising 11 accessions was selected from a biossay of 18 isolates on 19 host accessions using principal component analysis. A similar analysis of anthracnose severity data for a subset of 195 isolates on the 11 differentials indicated that an adequate summary of pathogenic variation could be obtained using only five of these differentials. Of the five differentials. S- seabrana "Primar" was resistant and S. scabra "Fitzroy" was susceptible to most isolates. A cluster analysis was used to determine eight natural race clusters using the 195 isolates. Linear discriminant functions were developed of eight race clusters using the 195 isolates as the training data set, and these were applied tio classify a test data set of the remaining 101 isolates. All except 11 isolates of the test data set were classified into one of the eight race clusters. Over 10% of the 296 isolates were weakly pathogenic to all differentials and another 40% were virulent on just one differential. The unclassified isolates represent six new races with unique virulence combinations, of which one isolate is virulent on all five differentials. The majority of isolates came frm six field sites, and Shannon's index of diversity indicated considerable variation between sites. Pathogenic diversity was extensive at there sites where selected germ plasm were under evaluation, and complex race clusters and unclassified isolates representig new races were more prevalent at these sites compared with sites containing wild Stylosanthes populations.  aCerrado  aColletotrichum Gloeosporioides  aDistribuição Geográfica  aVariação Genética  aBrasil  aPatologia vegetal  aStilosante1 aFERNANDES, C. D.1 aCHARCHAR, M. J. d'A.1 aTHOMAS, M. R.  tEcology and Population Biologygv. 92, n. 5, p. 553-562, 2002.