Tapan Kumar Dey
Senior Scientific Officer
Tuber Crops Research centre, BARI
M. Hossain
Senior Scientific Officer
Tuber Crops Research centre, BARI
TPS origin was more resistant to P. infestans compared to tuber germplasm. They required more incubation time to express their initiation of symptoms. In tuber germplasm, the cultivar Dheera took more than 80 hours to exhibit late blight symptoms. Out of 37 germplasm, only 5 germplasms (TPS origin) showed resistant to disease. There were found six germplasms as moderately field resistant, 11 germplasms as moderately susceptible and 15 germplasms showed susceptible to late blight.
Screening, Potato, Germplasm, Late Blight
Pest Management
To locate resistant sources if any through artificial inoculation.
Thirty seven (22 tuber and 15 TPS) germplasm of potato were screened artificially following “Detached leaf method” against P. infestans. Five healthy leaves per germplasm were used. The inocula were prepared in sterile water having a concentration of 2950 sporangia/ml. Initially the culture of P. infestans was maintained on tuber slice. Inoculation was done by putting one drop of inocula suspension on dorsal surface of the young apparently healthy leaf. Incubation was done for seven days providing 18+20 c with ensuring more than 50% relative humidity. Finally the response of the germplasms to P. infestans was assessed by following modified scale:
Immune :No infection or necrotic fleck with no sporulation
Field Resistant :Lesions restricted (not more than 2mm in dia with up to 600 sporangia per leaflet.
Moderately Resistant :Lesions very slow progressive, not more than 5 mm diam. with 601-1200 sporangia/leaflet
Moderately Susceptible :Lesions moderately progressive, having 5-8 mm diam. with 121-2500 sporangia/leaflet.
Susceptible :Lesions rapidly progressive, more than 8mm diam. with more than 2500 sporangia/leaflet.
Annual Report- 2001-02
50,000/-
The seed tuber from TPS origin was more resistant to P. infestans compared to tuber germplasm. Out of 37 germplasm, only five germplasms (TPS origin) showed resistant to disease and six germplasms found as moderately field resistant.
Report/Proceedings