Choice of improved phenotyping methods for bean plant reactions to white mold by non-linear model adjustments of symptom progression

Abstract

White mold, caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary is currently one of the major diseases affecting bean cultivars, especially in irrigated crops, and extremely difficult to control. Genetic improvement in the form of more resistant lines has been sought for inclusion in the integrated management of this disease. When selecting resistant genotypes, an efficient, fast and simple evaluation method regarding plant reactions to the pathogen is required. In this context, the aim of the present study was to compare straw and seedling phenotyping methods in the evaluation of disease progression by nonlinear models and evaluate the interaction of the phenotyping method with genotype resistance and evaluation timeframes. The results indicate that both phenotyping methods are well correlated regarding bean resistance groups. The applied methods lead to distinct inferences on genotype resistance, and disease progress is closely linked to the resistance level of the evaluated genotype. Both phenotyping methods are efficient, but in different situations. The symptom progression models display similar adjustments to the symptom levels of both methods.