Evaluation Of Maize Germplasm For Resistance To Rhizoctonia Solani And On The Biological Character And Electrophratic Analysis Of Rhizoctonia Zeae

Maize germplasm were identified and evaluated for resistance to sheath blight caused by Rhizoctonia solani. The biological characters of R.zeae and soluble protein, isoesterase patterns of isolates of R. solaniAG1-IA and R.zeae were studied.161 maize germplasm were identified and evaluated for resistance to sheath blight caused by Rhizoctonia solani. The results indicated that no immune or highly resistant germplasm was found. The percent of resistant and moderate resistant germplasm were 2.5%, 5.0%, respectively. Most of the tested germplasm were susceptible. The percent of susceptible and highly susceptible germplasm were 19.9%, 72.7%, respectively. Plant height, ear height and the ratio of ear height and plant height were negatively correlated with the disease index. The ratio of lesion height and plant height and ear height were positively correlated with the disease index. The lesion height was not correlated with the disease index. The ratio of lesion height and ear height could be used to evaluate the resistance of maize to corn sheath blight.The cultural characters, effect of temperature, pH, carbon source and nitrogen source on the mycelium growth and sclerotia production of R.zeae were tested. The results indicated that the cultural type, colony color and the rate of mycelium growth and the production of sclerotia of R.zeae were various. The range of temperature for mycelium growth was 10-35℃, and the optimum temperature was 30-35℃.The range of pH for mycelium growth was 3.0-10.0, and the optimum pH was 6.0-7.0. The optimum temperature and pH for scolerotia production was 25℃ and 6.0 respectively. The most suitable carbon source and nitrogen source were glucose and glycine respectively, and inulin, (NH₄)₂SO₄ were not suitable for mycelium growth.Soluble protein and isoesterase patterns of i?.^o/a?/AGl-IA and R.zeae from different locations in ya'an were studied by polyacrymide gel vertical electrophoresis. The patterns of soluble protein and esterase were various in different species, but similarly in same species. The species specific protein and esterase bands of R.solani AGl-IA and R.zeae were found. The results could be used in practice of classification as an additional taxonomic criterion to distinguish the two species.