Determination of prevalence, incidence and severity of powdery scab disease caused by spongospora subterranea in commercial potato seed lots and it's morphological and molecular identification

This study was conducted to investigate the rate of catching, severity and prevalence of "powdery scabies (Spongospora subterranea)"in some potato varieties. For this purpose, 107 seed lots belonging to 67 potato varieties (Agata, Agria, Alegria, Alonso, Amarin, Amora, Aurea, Banba, Blondine, Bohemia, Borwina, Brooke, Carrera, Casablanca, Chalenger, Concordia, Electra, Endeavor, Estrella, Fasan Lady Rosetta, Lady Amarilla, Lady Anna, Laura, Lovisana, Madeleine, Marabel, Marfona, Melody, Menger, Musica, Nahita, Jerry, Lady Claire, Fatih, Florice, Galata, Granola, Hermes, Innovator, Nam, Natascha, Nectar, Onaran, Opal, Orchestra, Pomqueen, Provento, Royal, Russet Burbank, Soprano, Safrane, Sagitta, Sante, Savanna, Sifra, Slaney, Soleia, Soraya, Surya, Taurus, Ünlenen, Van Gogh, WR- 808, Zorba) obtained from research institutes and commercial seed companies. Potato varieties were firstly examined morphologically and then examined by a stero microscope and scored according to the degree of distribution of the malignant lesion. Some varieties detected at high rates of disease incidence; Laura and Galata were found to be (96 %), Estrella (88 %). The varieties where prevalence rates are high; Laura, Galata, Estrella were determined as (100 %). Some potato varieties in which disease severity is high; Laura was (57.6 %), Galata (48 %), Estrella (43.2 %). The varieties in which the rate of disease incidence is low; Safrane (4 %), Innovator and Provento (4.3 %). The varieties detected in low disease severity; Innovator (0.9 %), Provento and Lady Anna (1.7 %). Prevalence rates for Innovator, Provento, Safrane varieties were found to be (100 %). The disease have not been detected on Endeavor, Musica and Ünlenen varieties. S. subterranea was morphologically characterized by tissue staining method with methylene blue and saffron dyes from the lesioned area to display resting spores. Species-spesific PCR and DNA sequence analysis were performed for molecular characterization of the pathogen.