Screening of some marigold cultivars (Tagetes erecta and T. patula) for resistance against leaf spot and flower blight caused by Alternaria zinniae Pape.

摘要

Three cultivars of African marigold (Tagetes erecta) and 14 cultivars of French marigold (T. patula) were screened during 2006-07 under natural epiphytotic conditions in Solan, Himachal Pradeh, India, against leaf spot and flower blight disease, caused by A. zinniae. Only the African Marigold cultivars, namely Pusa Narangi (87.60%), Pusa Basanti (84.50%) and Crackerjack (81.30%), were found to be highly susceptible to the leaf spot disease, while in French marigold, 10 cultivars, i.e. Hero Bee (4.33%), Cupidon Varie Orange (4.90%), Hero Harmony (5.00%), Cupidon Varie Yellow (5.60%), Safari Yellow (7.00%), Honey Comb (9.50%), Nana Jumbo Bicolor (9.58%), Safari Tangerine (9.60%), Safari Queen(10.00%) and Golden Boy (10.00%), exhibited resistant reaction towards the disease. Two cultivars, Bonanza Bolero (50.60%) and Single Petal Red (56.90%), showed susceptible reaction whereas Harmony boy (23.58%) and Sunkist (38.00%) were found moderately resistant and moderately susceptible to the leaf spot disease, respectively. The leaf spot severity was more pronounced than the flower blight. The incidence of flower blight was high in African marigold (66.50-76.60%) compared to French marigold (4.50 to 60.20%). Two cultivars of French marigold, namely Hero Bee and hero Harmony, developed minimum incidence of 4.50 and 4.60%, respectively, during both years.