Assessment of resistance in French bean genotypes against Meloidogyne incognita and Sclerotinia sclerotiorum

Meloidogyne incognita and Sclerotinia sclerotiorum pose a serious threat to the successful cultivation of French beans. Being soil-borne pathogens, M. incognita and S. sclerotiorum also form disease complexes that are more difficult to manage. The use of host resistance is the most economical and eco-compatible strategy to avoid crop losses. Considering this objective, in the present study, thirty-eight genotypes of French bean were screened against M. incognita and S. sclerotiorum in two separate set of experiments using artificial methods and were categorized according to their reaction against the respective pathogen. The promising genotypes were also assessed for post-inflectional biochemical changes. Among the total thirty-eight genotypes screened, none of the genotypes was found immune to the nematode as well as sclerotinia wilt. However, eight genotypes (FBK-9-2, FBPVAR-4-1, FBPVAR-11-2, FBK-14-2, FBK-14, FBP-1, FBPVAR-5, FBK-6) exhibited moderately resistant reaction against M. incognita while four genotypes (FBPVAR7-2, FBPVAR-4, FBPVAR-11, FBP-1) showed moderately resistant reaction against S. sclerotiorum. The post-inoculation biochemical analysis of the selected genotypes showed an increase in the level of biochemical parameters in all the genotypes but the increase was more in genotypes exhibiting resistant response. The resistant genotypes identified in the current study can be utilized to strengthen the French bean resistance breeding programme against these pathogens. The information generated on the post-inoculation changes in biochemical parameters could be explored as biochemical markers to identify the resistant source(s).