| 393 Trichoderma isolates isolated from 13 different counties and cities in Sichuan province. There were 168 isolates of T.harzianum, 44 isolates of T.koningii, 40 isolates of T.pseudokoningii, 34 isolates of T.aureoviride, 8 isolates of T.viride, 3 isolates of T. citrinoviride, and 1 isolate of T.hamatum. The 393 isolates of Trichoderma spp. which were used in dual culture, shoude different degrees of antagonistic effects on 2 pathogenic fungi: Fusarium oxysporum f.sp.cucumerinum and Phytophthora capsici.. The 1.5％strains of the 393 isolates against Fusarium oxysporum f.sp.cucumerinum were higher inhibition rates than 80.00％; the 1.27％strains of the 393 isolates against Phytophthora capsici were higher inhibition rates than 70.00％. Then, there were 13 isolates had higher antiogonistic effects on Fusarium oxysporum f.sp.cucumerinum and Phytophthora capsici. Of the 13 isolates, T55 showed that the greatest antiogonistic effect against Fusarium oxysporum f.sp. cucumerinum were 80.16％; T25 showed that the greatest antiogonistic effect against Phytophthora capsici were 80.77％.The test of antibiosis of 13 screen isolates showed non-volatile substances of the isolates had higher inhibition than volatile substances of the isolates to pathogens. T55 and T315 showed higher inhibition rates than 50％. Inhibition rates of T55 were highest in 13 isolates, the inhibition rates of T55 to Fusarium oxysporum f.sp.cucumerinum were 75.53％and to Phytophthora capsici were 54.26％.The test of hyphal growth rate and amount of sporulation showed that most of Trichoderma strains growth rapidly. Hyphal growth rate of T237 was fastest, sporulation of T25 was largest, and sporulation of T55 was very little. However, the test of against the inferior showed that T55 could growed well under pH=4, 9 and 10 as well as at 5℃, 10℃and 35℃. The experiment used technique in order to be improved Trichoderma strains and expand strain antibacterial spectrum. Protoplast fusion using morphological characteristics marking, colony back of T55 was significantly brown. Therefore, T55 and T25 were applied as parent strains to conduct fusion.The influence of mycelic age, enzyme proportion, osmotic stablzer-buffer systems, enzymolysis time as well as medium composition on the protoplasts and protoplasts regeneration of Trichoderma strain T25 and T55 were invistigated. The course of releasing and regeneration of protoplast was systemically observed. The optimal conditions of potoplast preparation of T25 were as follows: 13mg/mL driselase, osmotic stablzer-buffer systems composed of 0.2mol/L PBS, pH5.8 and 0.6mol/L NaCl, protoplast were obtained after 3-hour treatment of the 20h-old mycelia at 30℃. The number of the protoplast was about 9.0×10~6 cfu/mL. The others were shoued as followws: 13mg/mL driselase, osmotic stablzer-buffer systems composed of 0.2mol/L PBS, pH5.8 and 0.6mol/L NaCl, protoplast were obtained after 3-hour treatment of the 26h-old mycelia at 30℃. The number of the protoplast was about 6.33×10~6 cfu/mL. The medium of protoplasts regeneration composed of Czapek medium that containing 0.5％yeast extract and 0.5％Calium pantotthenic and NaCl. The regeneration rate was 1.150％and 0.785％, respectively.The study of inactivation protoplast showed that the inactivation temperature of T55 were between 50℃～55℃. Two protoplasts of T25 and T55 that inactivated were fused in promoting the role of PEG, and then has been 58 strains of fusion.The fusants that had stronger potential ability to pathogens for next study were screened through dual culture on PDA plates, effects of metabolites and test of sporulation f11, f15, f43, f41, f39, f37, f42 and f24 were screened for aim strains, and study them. The result of dual culture showde f11 and f15 had higher antiogonistic effect against pathogens than parent's stains.
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