The Mechanism And Genetic Analysis Of Resistant On Corn Hybrid Jingke 968 To Ostrinia Furnacalis

Asian corn borer(ACB),Ostrinia furnacalis(Guenée),is a major pest on corn in China.Corn hybrid Jingke 968,bred by the Maize Research Center of Beijing Academy of Agriculture & Forestry Sciences,is one of the main commercial corn varieties with good comprehensive characters.In order to understand the resistance of Jingke 968 to ACB,Jingke 968,its female parent inbred line Jing724 and male parent inbred line Jing92 were selected in the experiment,susceptible inbred line Zi 330 to ACB was selected as the control.The resistance of Jinke 968 and its parents to ACB in whorl leaf stage and tassel stage were evaluated by using the field resistance and life table technique,and the growth and development of the ACB fed on different tissues of the tested corn variety or inbred lines also were compared.The activities of main defense enzymes and the content of main components of cell wall in corn tissues were detected in order to analyze the relationship between the content of the nutrients and secondary metabolites in corn tissues with the resistance to ACB.The mechanism of corn resistance to ACB was discussed in this experiment.The main results are as follows:1.The field resistance identification of corn varieties were conducted from three aspects,including fed-leaf scale,The degree of stem borers of the first and two generations of ACB.Results showed that the resistance level against ACB of the tested corn hybrid or inbreds were arranged as follows from resistant to susceptible: Jing 92> Jingke 968> Jing 724>Zi 330 in corn whorl leaf stage,and Jingke 968>Jing 92> Jing 724>Zi 330 in tassel stage.2.The growth and development of the ACB fed on different tissues of the tested corn varieties or inbred lines were compared by using the life table.The results showed that ACB had different fitness to same tisusses of different corn varieties and different tissures of same corn varieties to ACB.The populations fed on Jingke 968 and Jing92 had longer development duration and lower eggs hatch rate.The ACB population fed the whorl leaf showed lower pupation rate,emergence rate and fecundities than the populations fed other tissues in the same variety.The results of life table were consistent with the results of resistance identification in field.3.The content of total soluble sugar,the total protein and the activities of five major defensive enzymes in different tissues of different corn varieties were tested by using spectrophotometer.The contents of soluble sugar and protein in corn had different effects on its insect resistance in different stages of corn.ACB prefered corn varieties with high content of soluble sugar and protein.The activity of these three enzymes,polyphenol oxidase(PPO),phenylalnine ammonia lyase(PAL)and superoxide dismutase(SOD),were significantly positively correlated with corn resistance to ACB and played an vital important role in corn resistance to ACB.4.The quantitative analysis of 20 kinds of amino acid in corn tissue were determined by using the HPLC-LCMS/MS API3200 Q-TRAP.The types and content of amino acids that are positively correlated with corn resistance are different indifferent corn tissues.5.The contents of cellulose,hemicellulose and lignin in different tissues were measured by chemical method.Their contents were positively correlated with the corn resistance.The data analysis showed that the content of lignin was significantly positively correlated with corn resistance in whorl leaf.6.The contents of DIMBOA in different tissues of different corn varieties were determined by LCMS-8040 system The results indicated that the resistence of corn whorl leaf was not completely dependent on DIMBOA,and DIMBOA-Glc,MBOA and HDMBOA-Glc also played a significant role.Their content was positively correlated with corn resistance to ACB.This experiment systematically evaluated the resistance of Jingke 968 and its parents to ACB.The resistance level to ACB of the tested corn hybrid or inbreds are arranged as follows from resistant to susceptible: Jing 92> Jingke 968> Jing 724>Zi 330.Planting corn hybrid Jingke 968 will have a better control effects on ACB.