01990naa a2200265 a 450000100080000000500110000800800410001910000240006024500770008426000090016152012560017065000170142665000210144365000120146465000280147665000230150465000250152765300210155265300130157365300150158665300170160165300200161870000190163877300670165710506692014-11-28       1996    bl ---       0--  u    #d1 aCOELHO NETTO, R. A.  aMethod for evaluating bean genotype reaction to Macrophomina phaseolina.  c1996  aReaction of 30 genotypes of beans (Phaseolus vulgaris L.) to Macrophomina phaseolina (Tassi) Goid. was studied using a simplified greenhouse procedure, or the tooth-pick inoculation technique and was correlated to the exudation of nutrients by the imbibing seeds. The seeds were planted over a layer of about 1-mm of sclerotial inoculum, evenly spread over the methyl-bromide fumigated soil in trays. The seeds were then uniformly covered with about 2-cm layer of the same soil. The trays were placed in a greenhouse where temperature varied  from 25 to 31oC and were watered as needed. Pre-emergence seedling blight incidence was determined 12 days after seeding by examining the unemerged seeds and seed-lings. The incidence of post-emergence seedling blight was evaluated 22 days after seeding, by the rating disease severity on cotyledons and hypocotyls of the surviving seedlings. The percentage of seedling survival at the first trifoliolate stage was the best indicator of the bean germplasm response to M. phaseolina. However, disease severity on the cotyledons and hypocotyls also was a good indicator of bean response to the pathogen. The correlation between cotyledon or hypocotyl disease index and seedling survival was highly significant.  acharcoal rot  aDoença Fúngica  aFeijão  aMacrophomina Phaseolina  aPhaseolus Vulgaris  aVariedade Resistente  aAshy-stem blight  aControle  aResistance  aSeed exudate  aSeedling blight1 aDHINGRA, O. D.  tFitopatologia Brasileiragv. 21, n. 24, p. 236-242, jun. 1996.