| Southern Leaf Blight caused by Bipolaris maydis is a member of the ascomycetes, thesac fungi, was one of significant Diseaseans in corn growing area in China. There werephysiol difference in Bipolaris maydis, and Bipolaris maydis could be divided into threesubspecial which were Race T, Race C, Race O and S type. With the renewing of maizevariety and changing of cropping system, something new happened on the harmness andpathogentic bactiem differeciation. It is significant to identify the pathogentic bactiemdiffereciation and the virulence vary tendency. The results of the study are as follow.1The isolation frequency and the the types of Physiacial race. Two hundred andeighty nine isolates of Bipolaras maydis, collected from Huang-Huai-Hai region from2009to2010, were identification hosts. Results showed that there are four isolation inHuang-Huai-Hai region, the isolation frequency that of race O overwhelms the other racesand S type s. it suggested that race O could be the dominant race of Bipolaris maydis in thecorn grown area of the region of Huang-Huai-Hai region. pathogenic difference in O Race,the areas of utmost isolation frequency of strong pathogenic strains of Race O is Henanprovince with the isolation frequence of28.55%, the areas of utmost isolation frequency ofmodesty pathogenic strains of Race O was Henan province with isolation frequency of34%,the areas of utmost isolation frequency of weak pathogenic strains of Race O was Hebeiprovince with the isolation frequency of37.66%.2The tendence of vitulence varying in O Race of Bipolaras maydis. with addinggeneration of the continous infection on different breed line, it became stronger on thesporation and virulence no matter strong pathogenic strains of Race O or weak pathogenicstrains of Race O. The sporation of weak pathogenic strains of Race O congtinous infectionresistance non-resistance inbred line were higher than that of Race O congtinous infectionresistance inbred line. The sporation of strong pathogenic strains of Race O congtinousinfection resistance inbred line were higher than that of Race O congtinous infectionnon-resistance inbred line3The diversity analysis of Bipolaris maydis by AFLP. Two AFLP reaction system,enzyme combination of Haeâ…¢/Pstâ… and EcoRâ… /Mseâ… , were build up to analyse thediversity of98Bipolaris maydis, there were significant genetic difference in different dormin,different Races and different years. There was significant genetic difference among different Races, different domain and different years. We got the similar results in different years whenusing the AFLP of enzyme combination of EcoRâ… /Mseâ… to analysis the genetic diversity of111Bipolaris maydis including98Bipolaris maydis above. There was no doult that the AFLPreaction system with enzyme combination of Haeâ…¢/Pstâ… was more fitness to analyse thegenetic diversity of Bipolaris maydis than the system with enzyme combination ofEcoRâ… /Mseâ… . The AFLP was used to analyse the genentic difference of Bipolaris maydis ofsubculturing.All the above made the fundation for the studies of genetic diversity and other researches.Taking use of the system based on reaction with enzyme combination of Haeâ…¢/Pstâ… couldidentify physiological differentiation and space-time distribution tendency rapidly andprecisely for Bipolaris maydis... |
