Analysis Of Combining Abilities Based On Maize Receptor Inbred Lines And Determination Of Improvement Effect

Elite varieties are very important for the development of maize production and the increase of the income of the farmers and grain yield.Traditional maize breeding methods have long cycle and low efficiency,which can not meet the needs of modern maize production for varieties renewal.Chinese germplasm resources are limited,so the germplasm base of maize needs to be expanded urgently.It is the key to speed up the breeding process and improve the breeding efficiency to make clear the selection of lines from which generation,select several testers and identify locations.It is of great significance to introduce and utilize excellent maize inbred lines from developed countries such as the U.S.to broaden maize germplasm base and realize germplasm innovation.This study was based on S1-S5 generation lines and 20 maize new materials from 4 maize receptor lines and excellent the U.S.donor inbred lines.The aim of this study was to explore the selection response of generation and the number of testers and test environments to the effect of combining abilities,and the improvement effect of the U.S.germplasm on receptor inbred lines was evaluated to provide theoretical reference for breeding new varieties and broadening the germplasm base of maize.The main research results were as follows:1.The selection of lines should start from the S3 generation,which was representative.2.The results of general combining ability of GY and EH of only one tester were representative.The representative results of DS,KRN,KNPR and KM were obtained by two testers.PH and SL need three testers for combining ability identification.3.The results of general combining ability of GY,DS,EH,SL,KNPR and KM were representative from only one test environment,while the results of PH and KRN from two test environments were representative.4.Nine new maize materials,such as L1,L3,L7,L9,L11,L14,L15,L18 and L19,had higher general combining ability of GY and greater breeding potential,and could be used as new materials in breeding.5.As a favorable gene donor,maize inbred line E8501 could improve the GY,DS,PH,EH,SL and KM of the receptor PH4CV,which has great application potential and the inbred line PHN11,as a favorable gene donor,could improve the GY of PH4CV.6.The hybrid crosses L6×CA667 and L16×CA331 had the same maturity stage as the check Xianyu 335,with lower PH and EH,lower SL and the same KM.The GY was 2.40%and 2.75%higher than that of the check,respectively.This study was based on S1-S5 generation lines and 20 maize new materials from 4 maize receptor lines and excellent the U.S.donor inbred lines.After the analysis of combining ability,the best generation per plant was selected to accurately determine,the minimum number of tester and test environment required for the determination of combining ability.The improvement effect of the U.S.germplasm on the 4 maize receptor lines was also discussed to provide reference for accelerating the breeding process and germplasm improvement.