Combining Ability And Genetic Analysis Of The Major Characters For Maize Inbred Lines Derived From Maize×Z.mexicana

New germplasm with specific and excellent characteristics created by introducing favorable genes of exotic germplasm exert great significance on expansion of genetic basis of maize germplasm.For the purpose of identifying breeding potential value of the inbred lines with exotic genes,the combining ability effect of the main characteristics and their genetic regulation should be investigated.133 combinations were obtained according to incomplete diallel cross mode by using 7 wide-used maize inbred lines as female parents,and19 inbred lines derived from distance hybridization as male parents. The combining ability and hereditary parameters for main characteristics were analyzed.Meanwhile, the genetic correlations among the main characteristics as well as their combining abilities were studied. Genetic cluster analysis was performed on the 26 inbred lines at the same time.The results are as following:1.The combining ability effect analysis indicated that the performance of combining ability was complicated among different inbred lines and their characteristics.Among 19 inbred lines,1147 showed the highest positive GCA effect of tillering and prolificacy,1193 and 1169 showed comparatively higher GCA effect of prolificacy,and 1183 performed outstanding the highest positive GCA effect of yield per plant,ear diameter,Kernels per row,and 1164,1157,1193 higher.1153 showed comparatively high negative GCA effect of plant height,growth period and main gronomic characteristcs.Secondly, different combinations and their characteristcis showed different SCA effects.For example:K389×1162,156×1193 and R08×1168 performed high SCA effect of yield per plant,156×1147 and K389×1164 had the positive maximum SCA of tiller number and ear number,while R08×1156 and R08×1167 performed negative and positive SCA effect of main gronomic characters including plant height respectively,however,ZHENG 58×1147 and ZHENG 58×1160 showed the highest positive and negative SCA effect of growth period respectively.2.The analytical results of genetic parameters indicated that the additive gene effect of tillering and prolificacy was much higher than non-additive gene effect.But narrow heritability of the above characteristics was 48.66%and 36.12%respectively;they should be selected at the late generation. However,characteristics including plant height,leaf number,tassel and growth period were controled by the additive gene effects,and both broad and narrow heritability of which were higher.As a result, they could be selected at the early generation.Comparatively,both additive gene effects and non-additive gene effects dominated the leave area,and its heritability was low.Hence,it was not appropriate to select at the early generation.For the addictive gene effect of yield and its components was far more important than their non-additive gene effect,parents with higher GCA effct should be selected for conducting combination in breeding practice.Among those characters,the heritability for the ear diameter and ear rows were the highest(above 70%),while the ear lengh and barren ear tip length were low comparatively(below 40%),the other characteristics medimum between 50%-70%. Therefore,it is more effective to select ear diameter and ear rows at the early generation.3.Correlation analysis indicated that there was a significantly negative correlation between tiller number and yield per plant,which was harmfull for yield increase.However,it was found that tiller number was significantly negative correlation with plant height,which illustrated obtaining the tillering will coupled with increasing of plant height and biomass on maize breeding.Reversely,ear number was not significantly correlated with yield per plant at all,showed that it might not be effective to increase yield by increasing effective ear numbers.Although,tiller number showed a significant correlation with ear number.Both the characteristics showed complicated correlation with major agronomic as well as economic characteristics.As a result,the selection scheme should be planned and performed accordingly.Concerning corralation of general combining ability,yield per plant showed extremely significantly positive GCA correlation with ear diameter,kernel depth,ear rows,kernels per row,and other economic characters,as well as,significantly positive GCA correlation with ear height,leaf area, leaf number,and other agronomic characters.Combining ability effect of yield per plant was able to be elevated indireactly by selecting GCA effects of those charaters.Most GCA effects of other agronomic and economic characters showed insignificant correlation with GCA effect of yield per pant.It was illustrated that GCA effects of those charateristics and yield per plant were not easy to be polymerized.4.The 19 inbred lines and 7 wide-used elite lines were clusted into 9 groups by genetic cluster analysis.Among them,the firsr group had 9 lines including elite lines P178,156 and inbred lines 1160;The second group had 5 lines including elite line 698-3,K389 and inbred lines 1156;The third group included 3 inbred lines 1169,1191 and 1195;The fourth group included elite lines 48-2 and R08; The fifth group included 3 inbred lines 1154,1183 and 1189;While elite line Zheng58 and inbred lines1153,1193 and 1147 was clusted to the sixth to the ninth groups respectively.Different inred lines of different groups had different advantages,which had directive significance for maize breeding. Among them,inbred line 1147 performed tillering and prolificacy extremely,as well as higher plant height,and the GCA effct of those characters were more higher,so it had more potential value probably for forage maize breeding.1183 had large ear,more ear rows,high yield and high GCA etc,and it was a potential lines for high yield breeding.1153 had a short growth period and plant height,optimal plant-type and high kernel rate.Furthermore,its characters performed much higher GCA effect. Therefor it could be applied on breeding of early,drawf,and compact hybrids.As the other new inbred lines,each with a distinct identity could be improved and utilized appropriately based on the different breeding objective.