Study Of Mutation Screeing Strains And Laboratory Efficacy Evaluation For G.roseum IK726

Strawberry, cucumber, tomatoes and other fruits and vegetables are susceptible tobe infected by Botrytis cinerea in the planting process or after harvest, resulting in fruitflower, stem atrophy, fruit rot. Gliocladium roseum is a species of fungi exist widely innature. As biocontrol fungi, Gliocladium roseum has the advantages of fast growth,wide host range, strong parasitic ability, antagonistic mechanism diversity etc.Compared with the biocontrol agents have been commercial production, the wild typestrain sporulation is low, antibacterial effect is poor, it is unable to enter the stage ofindustrialization.The G.roseum IK726was conducted single factor mutagenesis of ultraviolet,temperature, sodium nitritea, composite mutagenesis breeding of temperature-sodiumnitrite and composite mutagenesis breeding of sodium nitrite-ultraviolet to determinethe best conditions for mutagenesis in this text. Study on the biological characteristics,antibacterial experiments and indoor pharmacodynamic of the mutant strain obtainedto evaluate its biological properties preparing for the field experiment.The best mutagenesis time has been found in this research, which is expressed asfollows: UV mutagenesis is120S, Temperature Mutagenesis is4min; Sodium Nitritemutagenesis is12min; the compound mutagenesis of Temperature and UV is thatTemperature Mutagenesis is4min, and then UV irradiated100S; the compoundmutagenesis of UV and sodium nitrite is that sodium nitrite for the first insulation12 min, and then UV irradiated100S. Through biological morphology, sporulation,antimicrobial activity screening, five excellent mutant strains were selected: UVG-4,TMG-1, NAG-3, TUG-1and NUG-2; the sporulation is respectively2.70,1.73,2.95,2.41and2.86times as large as the original strain. Genetic stability, biologicalcharacteristics and antimicrobial effect is better than the original strain. Throughsingle-point confrontation, multi-point confrontation test, screening out the NUG-2which characters were superior to other mutant strains. The original strain and themutant strain NUG-2carried out the indoor efficacy experiment, with the increasing ofspore concentration the antimicrobial activity of G.roseum enhanced. When the NUG-2spore concentration is1×106/mL, inhibitory rate of the gray mold hypha growth is95.01%; when the spore concentration is1×107/mL, the relative inhibitory rate on thegermination of spore is83.48%. The inhibitory effect of NUG-2on leaves ofstrawberry gray mold disease is the best, G. roseum is better to use before the onset of48h, it suggests that G. roseum is applicable to the prevention of Botrytis cinerea.