TRICHODERMA HARZIANUM RIFAI با آغشته كردن بذور گندم توسط استرينهاي PYTHIUM ULTIMUM TROW افزايش رشد گندم و كنترل بيولوژيكي

Increased growth of wheat and biocontrol of Pythium ultimum Trow with strains of Trichaderma harzianum Rifai

Increased grwoth of wheat resulting from amendment of soil with strains of Trichoderma harzianum was investigated to determine if increased growth could be attributed to a direct effect of these Trichoderma .spp. on the plant or a secondary effect due to control of plant pathogens. Three strains of T harzianum (T.95, T-1 2B and T-12) and its parents wild type (WT, isolated from a soil in Forteollins) were grown on PDA. After 24h. sterile and washed cellophane membrane was placed on the growing mycelium. Seeds of wheat cv. Oslo (dwarf) and Butte (tall) were sorface sterilized and placed on the membrane. The percentage of germination of seeds on the cellophane were more than the control (without T. harziarauni). This expriment revealed that the exudates of T harzicimum stimulated the germination of seeds. In the greenhouse experiments, wheat seed cvs Oslo and Butte treated with suspension of 10ʹ spores per ml. the strains of harzianum and type (WT), were sown in the soil infected with P.ullimurn (300 CPU). The percentage of the infected roor tips of the plants resulted from treated seeds was fewer than those of the control and wild type. The percentage of root pieces colonized by the propagules of the strains was more than the wild type. The fresh and dry weights of plants resulting from the seeds that have been treated with the ".harzianurrr were higher than the control. These experiments explore the possibility of biocontrol of some soil-borne plant pathogenic fungi with strains of T: harzianum and increased growth reponse.