Occurrence Tendency Of Fresh Corn Disease And Genetic Analysis Of Resistance Of Corn To Bipolaris Maydis In Guangdong Province

Corn is one of the major grain crops in China, whose cultivated area is the largestafter rice and wheat, occupying an important share and place in the food production plan.In recent years, fresh corn has been developed rapidly in China, especially in GuangdongProvince. Its cultivated area has accounted for60%of the country,10%of the world.Bipolaris maydis is a widely popular disease in the production areas of China and abroad.Bipolaris maydis can occur in the whole growth period. The rate of this disease can peakafter tasseling, and the leaves would die from being covered with disease spots. Theproduction of infected species can reduce over10%per year in general disease, and reduce20%-30%per year in serious disease. Recently, Bipolaris maydis is one of the three mostserious diseases in the corn areas of China, and it may become serious year by year, whichcan do tremendous harm to corn production. According the long-term practice, cultivatingdisease resistant species is the most effective and most direct way to solve this issue.At present, in the domestic and overseas, studies on Bipolaris maydis mainly focus onpathogen and pathogen interaction, but studies on genetic characteristics of diseaseresistance are too few. This study is including two aspects. This first one is the occurrencetendency of Bipolaris maydis in Guangzhou, and the second one is genetic characteristicanalysis of this disease resistance. The main research results are as follows:1.This study has organized and analyzed all relevant data for the prediction of cropdiseases from2008to2013in Guangdong, has concluded the occurrence situation andtendency in Guangdong recently, and has concluded the distribution of Exserohilumturcicum and Bipolaris maydis in Guangdong. The occurrence area had increased from2008to2013, with over30percentages of morbidity. Bipolaris maydis is the main diseaseof fresh corn in Guangdong with serious harm.2.This study selected high resistant selfing line PT01of Bipolaris maydis and infectedselfing line PT02as parental samples to hybridize from super-sweet corn materials in thecorn study room in Zhongkai agricultural college and made up F1、F2、B1and B2which are constituted six-generation materials with P1、P2. The major gene-polygene mixed geneticmodel is used for genetic analysis of resistant genes.That shows that the genetic model ofBipolaris maydis is E-1model. The resistance for Bipolaris maydis shows that the mixedheredity of additivity-dominance-epistasis major gene and additivity-dominance polygene.The resistance of Bipolaris maydis is controlled by two major genes which focus on theadditivity effect. This shows that the characteristic control of disease spots of Bipolarismaydis has focused on major gene heredity, and this illustrates that in the condition ofdisease nurseries of artificial inoculation, it is likely to get better expectant result in earlysegregating generations, and choosing resistant plant continuously is useful to increase theresistance for Bipolaris maydis.