ÃÞ»¨Ñ§±¨ C0tton Science 2005£¬l7(3)£º151-154
A New Selective Medium to Simplify Isolate Verticillium dahliae in Cotton from Naturally Infested Soil Abstract£ºA new selective medium to simplify isolate Verticillium dahliae in cotton from naturally infested soil was introduced. The medium consisted of following ingredients per liter distilled water£ºcotton leaves 100g, sugar 5g, agar 17-20g, 40% PCNB 0.3 g, chloramphenicol 0.05 g, streptomycin 0.05g and penicillin 0.05g, pH adjusted to 6.4-7.0. The medium was simple and quick. The microsclerotia V. dahliae from naturally infested soil could be effectively isolated while it was rarely infected by other pathogens. The colonies of V. dahliae on the medium were large black-colored, and the mean recovery rate of the number of V. dahliae inoculated in soil could reach 82. 88%. In addition, the microsclerotia Verticillium dahliae growth speed on this medium was the fastest. At the same time, the optimum determining duration was 21st days after microsclerotia V. dahliae from naturally infested soil were cultured on this medium. Alteration amount of leaves cotton quality in 1000ml medium had great effect on isolating. When it was low than 0.05g• ml-1 medium£¬the medium was rarely infested by other pathogens, but the rate of the number of the microsclerotia V. dahliae from naturally infested soil was lower, because there was insufficient nutrition. When it was high than 0.125g•ml-1 medium, although nutrition was adequate for microsclerotia development and the growth speed of V. dahliae on it was faster, the medium was seriously infested by other pathogens and it was gradually changed no transparence, so the rate of the number of the microsclerotia V.dahliae was lower, too.
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