Screening Of SSR Molecular Marker For Ht Resistance Gene To Northern Corn Leaf Blight And Seed Purity Identification Of Differential Hosts

In this paper, Ht resistance gene of differential host of Corn Leaf Blight and seed purityidentification with SSR（Simple Sequence Repeats）markers was studied systematacially,which were based on clear the population dynamics of physiological races of E. turcicum innortheastern China in2010. The resualts were as follows:1. Using routine technique, eighty-eight isolates of Exserohulum turcium, collected fromnortheastern China in2010, was identified on different resistant genes（Ht1, Ht2, Ht3and HtN）,and its race dynamics was investigated. The results showed that12races were identifiedamong these fungal isolates，including0,1,2, N,12,1N,23,2N,3N,12N,123N,123,23Nand13N. Among these races population, races0and1were predominant. The virulencefrequencies against genes Ht1, Ht2, Ht3and HtN was45.5%,30.7%,15.9%and23.7%respectively. The physiological race component and their inter-specific of E. turcicumvariability in northeastern China became complex and new races were frequently found.2. Four pairs of SSR primers can effectively labeled Ht1genes and three pairs of primerscan effectively labeled Ht2gene from corn inbred lines A619with Ht resistance genes weregot. On that basis, identification resistance and SSR analysis on F₂population from an elitehybrid （3162×A619Ht1and3162×A619Ht2） with contains Ht1and Ht2genes. The resultsshowed that disease resistance of F₂population appeared resistance symptom and susceptibleof F₂population appeared susceptible symptom. SSR analysis with7pairs of primer weredetected for F₂population specific Ht gene by PCR amplification. It turned out that three pairsof primers have amplified polymorphism and effective segregation on F₂population withcontains Ht1gene. And the proportion of resistance plants and susceptible plants is3:1. Twopairs of primers have amplified polymorphism and effective segregation on F₂populationwith contains Ht2gene. And the proportion of resistance plants and susceptible plants is3:1.So these SSR molecular markers can effevtive detection Ht1and Ht2gene of theexperimental material.3. In this experiment, Screening of SSR molecular marker with121pairs of primers,which were located in different chromosomes of maize were detected for two sets of differential host of huangzaosi and B37specific Ht gene by PCR amplification. Nine pairs ofprimers can labeled Ht1gen effectively in Huangzaosi, six pairs of primers can labeled Ht2gene effectively, and one pair of primer can labeled Ht3gene effectively.But no polymorphismwas found in HtN gene. We have also get four pairs of primers can labeled Ht1gene in B37effectively, seven pairs of primers can labeled Ht2gene effectively, and one pair of primer canlabeled HtN gene effectively. But no polymorphism was found in Ht3gene.4. Seed purity identification with six pairs of SSR primers （phi072、bnlg439、bnlg1175、bnlg2291、umc2105and bnlg149） were detection for the purity of five sets of differential hostby PCR amplification. The results showed that the purity of Huang zaosi against genes Ht1,Ht2, Ht3and HtN were75%,60%,80%and65%respectively, average is70%; The purity ofB37were100%,90%,95%and80%respectively, average is91.25%. The purity of OH43were95%,90%,95%and95%respectively，average is93.75%; The purity of Pa91were100%,90%,95%and90%respectively，average is93.75%; The purity of V a26were95%,100%,95%and95%respectively, average is96.25%.Identificating the purity ofdifferential host for Ht resistance gene of corn leaf blight is the guarantee to cultivate highquality and excellent corn.