Research On The Genetic Characteristics Of Maize Head Smut Resistance And Heterosis

Head smut of corn (Zea mays L.) is a kind of worldwide disease, is also one of the main diseases of spring corn-producing areas in China. This disease spread through the soil or seed infection fungal diseases, pathogens wire axis black powder bacteria [Sporisorium reilianum (Kuhm) Langdon et Full] in maize seedlings underground part of the intrusion, the system infection, the adult stage performance of the typical symptoms, tassel and Ear produce spores of black powder, can cause the corn a lot of cuts, so the selection of quality disease-resistant hybrids is one of the control wire smut is the most effective way.This study selected15inbred lines with different resistance to Head smut,and56hybrid conbinations as the materials.Conbining abilities was processed in different conditions,including artificial inoculation and unartificial inoculation.1. The study found that10inbred lines resistant to head smut, accounting for66.6%of the total inbred lines, the inbred lines F349and Mo17proved high disease-resistant, PH6wc,5918, J1782, PH4cv, Dan8415East NO D202, Dan Huang34,106and other materials proved moderate resistance, the39hybrid combinations proved disease-resistant, accounting69.64%of total combinations.And proved that the resistance of the hybrid F1generation depends on their parents own resistance.Correlation analisis indicated the morbidity of F1is significantly correlated with the morbidity of the parents.So it is important to select the disease-resistant and high quality parents in breeding foe disease-resistant.2. Combining ability analysis indicated, general combining ability and specific combining ability of the various traits of Fl Hybrids impacted by the maize head smut fungus,and the impact of a different degree in various traits. And among these traits. ear weight and ear row number suffered impact is small, the GCA of yield per plant coincide with real value. The hybrid combination,which was produced by parents with the high GCA effects, has high yield,.Such as inbred lines6wc, Mo17, East D202and Dan8415, in correlation with the yield GCA effect has an advantage, through the analysis of the group with the control advantages of hybrid combinations yield per plant is also advanced. So they can produced a high yield hybrid combinations. The GCA effect of bare tip of inbred lines J1782and Dan Huang34is big, so they should be improved in this trait.3. through the genetic parameters analysis, the rows per ear and yield per plant is mainly controlled by additive genes. bare tip, ear weight, ear diameter, kernel weight by additive and nonadditive joint controled.The correlation analysis between the yield and resistance can be indicated that the high-yield combination after inoculation is not always the high-resistance,such as6wc×F349, Mo17×Dan8415and Mo17×East D202,they proved moderate resistance; the combination6wc×east NO D202,5918×Dan8415resistance for disease resistance, and its yield per plot was lower than the combination of anti-6wcDan×8415, J1061×F349, thus the combination of high resistance is not related to high yield. So we can try to select moderate disease-resistant and high GCA effect inbred lines as parents, the main heterotic pattern were: Reidgroups the×Ludahonggu group and the Lancaster group×brigade red bone group, through sisters cycle selection method, and then bred high disease resistance, high yield and excellent hybrid.4. Hybrid combination of higher6wcx east D202、6wc×Dan8415were selected due to the high combining ability and high yield.Through the incidence of the ABC model testing and genetic analysis of the effects of six generations, the results showed that the incidence of genetic is complex and controled by additive and non-additive effect. The incidence decreased by backcross, and the male parent backcross can get the better results compared with the female parent backcross. This study can provide a basis to the breeding for Head Smut-resisitance.