Study On Utilization Potential Of Foreign Introduction Maize Inbred Lines

Innovating germplasm resource with foreign materials is an effective way to broaden the genetic base of maize germplasm and to increase the genetic variance within heterotic group.The construction of the basic population for breeding inbred lines is an important step,but at present the mechanism is not very clear.To further improve the efficiency of maize breeding,16 USA maize inbred lines and seven important inbred lines of China were chosen as experimental materials,and 57 F1 hybridization combinations were prepared by NCII genetic mating design.And CA193 or CA749 were used as tester to cross with these 57 F1 combinations,and 57 three-cross hybrid combinations were produced.The combining ability and heterosis effect of the main agronomic traits of the 16 USA inbred lines were evaluated using incomplete block design at four experimental regions,including Gongzhuling of Jilin,Shenyang of Liaoning,Shijiazhuang of Hebei and Xinxiang of Henan.The combining ability of the 57 F1 combinations were also analyzed.The application potential of the 16 USA inbred lines in improving the seven Chinese backbone inbred lines was comprehensively analyzed,which laid a theoretical foundation for maize germplasm innovation.The main results are as follows:1.Eight of the 16 USA maize inbred lines,including Jing 66,PHB1 M,MBPM,PH6 JM,PH4CV,PH09 B,PH1CRW and XY828 M have higher yield combining ability,meaning they have great yield potential in breeding.In addition,Jing66 has the breeding potentials of shortening the growth period,reducing the lodging rate,increasing 100-grain weight and the number of ear rows,and shortening the length of ear bald tip;PHB1M has the breeding abilities of reducing the grain water content at harvest stage,increasing 100-grain weight and the number of ear rows,shortening the length of ear bald tip;MBPM can reduce the lodging rate and increase the 100-grain weight and the number of ear rows of its progeny;PH6JM can reduce the grain water content at harvest stage,increase 100-grain weight and shorten the length of ear bald tip;PH09B and PH1 CRW both have the breeding potentials of increasing100-grain weight and the number of ear rows,shortening the length of ear bald tip;XY828M can increase 100-grain weight and the number of ear rows.2.Combining the defects of the seven Chinese backbone inbred lines with combining ability and phenotype of tested lines and their corresponding F1 hybridization combinations,7F1 combinations are screened for germplasm innovation.Among the screened combinations,CA749 × PH09 B can be used for improving inbred line CA749;H446 × XY828 M can improve H446;Si 144 × PH6 JM can improve Si 144;W9706 × Jing66 can improve W9706;PHB1M,Jing66 and XY828 M and CA193 constitute the selected base group and improve the100-grain weight trait of CA193.3.Comparing the genetic similarity coefficient(GS)and polymorphism information(PIC)between the SS group and the NSS group and the 7 domestic backbones,it was found that the 7 maize inbred lines of the SS group were more than 9 The genetic basis of the introverted maize inbred lines of the NSS group is more extensive and the utilization potential is higher.