Evaluation of French Bean Genotypes with Slow Rusting Components Against Uromyces appendiculatus

In this study, 66 genotypes of French bean were screened against bean rust under glasshouse and feld conditions, of which, 11 genotypes with diferent degree of resistance/susceptibility were selected for measuring the slow rusting components. Both, incubation period and latent period were signifcantly and negatively correlated with infection frequency, disease severity and area under disease progress curve (aUDPc). Infection frequency was signifcantly and positively correlated with disease severity and AUDPC. The AUDPC was also signifcantly and positively correlated with disease severity while negatively correlated with uredium size. Factor analysis calculated using principal components revealed that factor I and II explained 65.97 and 15.45 per cent of the total variance, respectively. On the basis of scoring, it could be inferred that the fve germplasm accessions viz., EC400406, EC755318, EC405210, EC400442 and EC400390 having low and negative factor I scores demonstrated slow rusting characteristics i.e., longer incubation and latent periods, lower infection frequency, smaller uredia and less disease severity against bean rust. These germplasm lines might have slow rusting genes and therefore, can be efectively used in breeding programs for developing rust resistant cultivars.