Screening of malus genotypes against marssonina leaf blotch

Apple (Malus × domestica Borkh.) is attacked by several diseases causing economic damage and amongst them Marssonina blotch caused by Marssonina coronaria (Ell. & J. J. Davis) J. J. Davis is one of the most widespread diseases of apple and has posed a serious threat to this crop in India and abroad. Marssonina blotch was reported to cause direct losses by inciting severe defoliation in apple plants thereby affecting the fruit size, colour, quality and quantity, besides affecting the tree vigour and the fruit bearing capacity in the following years. The present study was conducted during the year 2014-15 in the Division of plant pathology SKUAST-K. The germplasm were procured from Division of Fruit Sciences SKUAST-K. The evaluation test was performed under artificial conditions in well-equipped polyhouse of Division of Plant Pathology SKUAST-K. To ensure the presence of any latent infection prior to inoculation the potted plants were constantly observed for two weeks. The experiment was carried out in CRD manner with two replications. The potted one year old apple seedlings were sprayed with the freshly prepared spore suspension 5×104 conidia ml-1 with the help of atomiser. Seventeen cultivars were evaluated to determine their resistance against the disease. It was observed that none of the cultivar exhibited resistance against the disease. However, nine cultivars were categorized as susceptible, seven cultivars were categorized as highly susceptible and only one cultivar Granny Smith showed the moderately susceptible reaction against the disease.