Field Screening of Garlic Genotypes for Identification of Resistant Sources against Purple Blotch Disease

Garlic (Allium sativum L.) is one of the oldest cultivated plants in the world and belongs to the family Amaryllidaceae. Purple blotch caused by Alternaria porri (Ellis) Ciferri is one such disease which causes a great deal of loss for farmers. The best method to manage purple blotch is to adopt resistant genotypes for cultivation, which is highly necessary in areas with a high incidence. In order to identify resistant sources, 37 genotypes were field screened under artificial epiphytotic conditions at AINRPOG (All India Network Research Project on Onion and Garlic), MARS (Main Agricultural Research Station), Dharwad during Rabi, 2019 and 2020. Results from two years showed that no genotype was immune to purple blotch. Among the genotypes tested, five genotypes viz., G50, Bhima Purple, DOGR426, DOGR543 and DOGR569 were resistant to infection (1-10%), 17 genotypes moderately resistant to infection (11-20%), while 4 genotypes were moderately susceptible to infection (21-40%). On a scale of 0 to 5, only one genotype (HRG Local) showed susceptible (41-75%) in reaction. Among the remaining genotypes, disease reactions differed between years. The genotypes that are resistant can be utilized by breeders to produce high yielding purple blotch resistant varieties.