Combining Ability Evaluation Of Maize Inbred Lines Breeded From Shaan A Group And Shaan B Group

In order to accurately evaluate the breeding potential of maize inbred lines bred by Shaan A and Shann B groups and accelerate the breeding process,in this study,the combining ability of yield characters of Maizes inbred lines,which were bred from Shaan A group and Shaan B group,was analyzed through the NC-II genetic mating design.By analyzing the variation of yield GCA of maize inbred lines and the relationship between parental GCA and yield of hybrid combinations under multi-point conditions in 2017-2018,making an accurate evaluation for the maize inbred lines bred from Shaan A group and Shaan B group.The main results are as follows:1 In the two-year experiment,the interaction effects among genotype,environment,gene and environment accounted for 8.87%,79.43%,7.87% and 6.81%,71.85% and 15.7% of the total variation,respectively;the heritability of yield traits was 85.34% and 82.12% respectively;the additive genetic variance of yield traits was 0.80-0.99 under different environments,indicating that environment was the main factor affecting yield traits,and compared with other effects of genes.It should be noted that additive effect has a greater impact on yield.2.The GCA of maize inbred lines bred from Shaan A group and Shaan B group was analyzed.It was found that 42.5% and 54.5% of the maize inbred lines of Shaan A group and Shaan B group could show positive effects at multiple points in the two-year experiment.This indicated that the GCA of maize inbred lines screened by multi-environment and high pressure could be expressed stably in different environments.Among them,inbred lines KA203,KA025,91227,Y161639 and Y161572 had high average GCA,low coefficient of variation and high&stable yield under different environments.3.Under different circumstances,the yield of hybrid combination is closely related to the GCA of parental inbred line yield(r=0.531**~0.825**).The yield of hybrid combinations will increase as the GCA increases of its parents.4.The yield of the parental inbred line yield GCA is also excellent in the hybrid combination with good yield performance,and as the threshold increases,the proportion of hybrid combinations with higher GCA in the inbred line will also increase.Yield GCA plays an important role in the process of maize breeding,and has a very important guiding significance for maize breeding of Shaan A group and Shaan B group.