01771naa a2200313 a 450000100080000000500110000800800410001910000200006024501030008026000090018352009030019265000160109565000180111165000130112965000160114265000180115865000140117665000110119065000090120165300190121065300270122970000190125670000170127570000160129270000160130870000200132470000230134477300900136710489682013-08-07       2006    bl uuuu     u00u1 u    #d1 aSILVA, M. R. da  aEstimates of repeatability in the evaluation of resistance of soybean genotypes to powdery mildew.  c2006  aSoybean is worldwide a crop of great importance, however, with its expansion, diseases causing great yield loss such as the powdery mildew surge (Erisyphe diffusa U. Braun & S. Takam). Objective of the present study was to estimate the ideal number of evaluations of the resistance of soybean genotypes to powdery mildew by means of repeatability studies with the traits: ILA (infection of the leaf area), ILS (infection of the leaf blade surface) and ILU (infection of the leaf underside), using the treatments no control - NC, partial control - PC (fungicide 80% sulfur at ILA &gt= 40%) and total control - TC (presence of symptoms). Only trait ILA presented estimates of repeatability (ANOVA and principal components), with 85-90% of stability in 3 or 4 measurements (PC and NC methods). These results and the high values found for R2 indicate that selection based on this parameter is possible.  aAgriculture  aBiotechnology  aGenetics  aAgricultura  aBiotecnologia  aGenética  aOídio  aSoja  aRepetibilidade  aVariância fenotípica1 aPEREIRA, D. G.1 aSEDIYAMA, T.1 aCRUZ, C. D.1 aREIS, M. S.1 aGOMES, J. L. L.1 aTEIXEIRA, R. de C.  tCrop Breeding and Applied Biotechnology, Londrinagv. 6, n. 2, p. 160-166, June 2006.