Screening of Indian Cardamom Accessions for Resistance to Major Pathogens and their Relationships with Biochemical Defense Parameters

Major fungal diseases reported in Indian cardamom (Elatteria cardamomum (L.) Maton.) are capsule rot/Phytophthora rot, clump rot, pseudostem rot/Fusarium rot, leaf blight, and tiller splitting/phoma disease. These diseases cause significant yield reduction regularly. Fifteen promising cardamom accessions were screened during 2022-23, to identify resistant sources against each disease. The screening studies were conducted at Cardamom Research Station, Pampadumpara utilizing cardamom accessions maintained at germ plasm bank. Five different experiments were conducted to screen accessions for resistance against each disease. The role of defense-related biochemical parameters viz., Peroxidase (PO), Polyphenol Oxidase (PPO), Phenylalanine Ammonia-Lyase (PAL), total phenol, OD phenol, β-1,3 glucanase, and chitinase that impart resistance against each pathogen in cardamom, as well as the correlation between percent disease index and biochemical parameters were investigated. The accessions hybrid-6, hybrid-17, and hybrid-1 showed resistance to three or more diseases indicate the possibility of using them as donor parents in future resistance breeding programmes. All biochemical parameters evaluated in this study were higher in inoculated plants than in un-inoculated ones. Among biochemical defense parameters studied, PO and β-1,3 glucanase were the significant biochemical defense indicators for Phytophthora rot resistance. In the case of clump rot and leaf blight, PPO and chitinase are the key indicators. The primary factor of resistance to Fusarium rot was PO activity. PAL and chitinase levels significantly influenced and correlated with resistance to Phoma disease. These indicators could be utilized in future to identify disease-resistant cardamom accessions and facilitate agile breeding initiatives.