Evaluation Of Combining Ability In Multi Environment Of Key Maize Inbred Lines From Shaan A Group And Shaan B Group

Maize inbred lines are the key to cultivating superior maize hybrids,and the core of evaluating superior maize inbred lines is combining ability.In order to evaluate the environmental effects of combining ability of different maize inbred lines,and to clarify the breeding potential of maize inbred lines from Shaan A group and Shaan B group,this study used the key maize inbred lines selected from Shaan A group and Shaan B group as materials.12 key maize inbred lines including 91227,KA052,KA060,KA064,KA074 derived from Shaan A group were screened,and 50 key maize inbred lines including KB020,KB024,KB025,KB031,KB035 derived from Shaan B group were screened.Based on NCⅡ genetic design,600 hybrid combinations were assembled.Through the Multi-environment Trial of combining ability,the environmental effects of combining ability and the relationship between combining ability and yield were clarified,and the dominant hybrid combinations were screened.The main results are as follows:1.Environmental effects accounted for 53.02% of the total variation,and were the main factors affecting yield and combining ability,followed by genotype effects and genotypeenvironment interaction effects.The generalized heritability of yield,general combining ability and special combining ability were 83.40%,91.36% and 70.06%,respectively.General combining ability was mainly affected by genetic factors and was more stable.2.Three types of methods were used to evaluate the general combining ability of maize inbred lines of Shaan A group and Shaan B group.In the performance of different environments,the general combining ability of Shaan A group bred maize inbred lines KA203,KA105,KA103,KA052 and Shaan B group bred maize inbred lines KB092,KB102,KB588,KB121,KB561,KB070-2,KB020,KB179-2,KB070-1,KB179-1,KB227,KB079 was higher,and showed positive effect in five environments.In response to the environment,the coefficient of variation of the maize inbred lines KA203,KA105,KA103 was bred in Shaan A group,KB092,KB102 bred in Shaan B group is small,and the response range to environmental changes is stable.In the GGE analysis,the maize inbred lines KA105,KA203 and KA103 bred in Shaan A group and the maize inbred lines KB092 and KB102 in Shaan B group have good environmental adaptability and are closest to the ideal inbred lines.3.In the evaluation of the special combining ability of the hybrid combination,the special combining ability of the combination KA327×KB106,KA060×KB243,KA074×KB215 and KA052×KB207 is excellent in five environments and has good environmental adapt ability,and has a certain special combining ability application potential.4.In the evaluation of the yield performance of the hybrid combinations,the yield performance of the hybrid population of the maize inbred lines KA103,KA105,KA203 bred by the Shaan A group,KB092,KB102,KB079,KB588 and KB179-2 bred by the Shaan B group is better.Compared with the control varieties,the hybrid combinations KA105×KB092,KA203×KB121,KA052×KB207,KA103×KB227 have greater potential for increasing yield,and have better high yield and stable yield.5.The general combining ability and the special combining ability jointly affect the final performance of the yield.The contribution rate of the two to the increase of the yield is different.The correlation between the yield and the general combining ability(r=0.78***)is higher than that of the special combining ability(r=0.59***).The parental general combining ability has a significant effect on improving the yield of hybrids,and the general combining ability of parents of high-yielding hybrid combinations is better.As the yield of hybrids increases,the proportion of hybrid combinations with a higher general combining ability basis also increases.In conclusion,Multi-environment Trial is an effective means to identify excellent maize inbred lines.Maize inbred lines will have specific responses to environmental changes.Combining ability evaluation of maize inbred lines under multiple environmental conditions can clarify its true breeding potential.In the breeding work,in order to improve the breeding efficiency,the general combining ability of the inbred lines should be improved as the main line to improve the yield basis;at the same time,the testing and breeding should be expanded on this basis to improve the special combining ability to obtain a secondary increase in yield.