V. V. Vasilchenko, A. N. Smirnov
Russian State Agrarian University – Moscow Timiryazev Agricultural Academy ul. Timiryazevskaya, 49, Moskva, 127550, Russian Federation
Abstract. The authors estimated the role of a cultivar, a pathogen and an infectious load on aggressiveness manifestation of Phytophthora infestans and Alternaria alternata on potato tuber slices of cultivars ‘Zhukovsky Ranny’, ‘Red Scarlett’, ‘Sarpo Mira’, ‘Lugovskoj’, ‘Udacha’. After a single inoculation with pathogens, they were incubated in humid chambers for 12 days at a temperature of 20–22 C. A composite aggressiveness index (CAI) was calculated for the isolates 161 of P. infestans and 10 of A. alternata: CAI = (LA x SC) / (IP x LP), where LA is a lesion area, SC is a sporulation capacity, IP is an incubation period, LP is a latent period. The results were interpreted by means of a three-factor analysis of variance: factor А is a cultivar; factor B is contamination by P. infestans zoospores, A. alternata conidia, and there mixture in the ratio of 1:1 (v/v); factor С is a concentration of pathogen inoculum. The maximum concentration was 30,000 zoosporangia of P. infestans and 25,000 conidia of A. alternata in 1 mL, as well as their dilutions were tested (1/2 and 1/4). The greatest CAI (1.00) was registered at P. infestans inoculation of Zhukovsky Ranny cultuvar, the least CAI (0.04) was noted at inoculation of Sarpo Mira cultivar with A. alternata conidia. For Lugovskoj cultivar the CAI of P. infestans was 0.15–0.56, the CAI of A. alternata was 0.28–0.69; for Red Scarlett the value of these indices were 0.57–0.73 and 0.21, respectively; for Zhukovsky Ranny – 0.56–1.00 and 0.16–0.20; for Sarpo Mira – 0.28–0.89 and 0.04–0.15, for Udacha – 0.71–0.83 and 0.11–0.13. He CAI of the pathogen mixture was average between P. infestans and A. alternata. As the concentration of the propagules decreased, the values of the CAI decreased. But at inoculation of Red Scarlett cultivar by P. infestans in the dilution of 1/4, the CAI was higher than in the case of 1/2 (0.63 and 0.57, respectively). For Udacha cultivar CAI was lower in the case of the maximal concentration than in the dilutions of 1/2 and 1/4 (0.71, 0.83 and 0.75, correspondingly).
Keywords: potato late blight; potato early blight; aggressiveness; Phytophthora infestans; Alternaria alternata.
Author Details: V. V. Vasilchenko, post graduate student (e-mail Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); A. N. Smirnov, D. Sc. (Biol.), prof. (e-mail Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.).
For citation: Vasilchenko V.V., A.N. Smirnov. Short-Term Viability of Pathogens of Late Blight and Alternaria Spot of Potato under Laboratory Conditions. Dostizheniya nauki i tekhniki APK. 2018. Vol. 32. No. 6. Pp. 49-52 (in Russ.). DOI: 10.24411/0235-2451-2018-10612.