Analyzing On Important Generic Characters And The Improvement Potential Of12Maize Populations

It is very important to partition heterotic group and build up heterotic patterns based on the analysis of the originality, the genealogical relationship and the generic difference of the maize generic characters for avoiding the blindness of hybrid and improving the efficiency of breeding, as the generic basis of maize group is very wide. In this study, we aimed at (1) improving the improvement efficiency of artificially synthesized maize populations and (2) providing scientific basis for maize germplasm innovation and hybrid improvement through partitioning heterotic populations, determining heterotic improvement patterns, and filtering the top quality populations with wide improvement prospect and high breeding potential. The phenotypic character, combining ability, hetarosis, densification effect, etc aspects of12maize populations, including7self-breeding maize populations, MengQunl to MengQun4, MengAQun, MengBQun, MengCQun,2internal maize populations, Zhongzong5and Zhongzong7, and3Canada populations, CQunl to CQun3, were analyzed by field identification and molecular level detection. The inbred line B73、Mo17、Dan340、Huangzao、Ye478were the tested varieties. The main results were listed below.1. Based on grey relativity analysis, the most closed interrelated agricultural characters of these12populations associated with maize yield is seed rate, followed by kernels per row, spike diameter,100-seed weight, plant height, number of grains per spike, spike length, number of rows per spike、ear height and the length of the bald; the order of agricultural characters, which is closed associated with content of crude protein, crude fat, crude starch, and lysine, etc nutrient quality, is number of grains per spike,100-seed weight、number of grains per row, seed rate, number of rows per spike, plant height, spike diameter, ear height, length of spike and the length of the bald.2. In the GCA effect analysis on15agricultural characters of these12maize populations in the eastern, western and central area of Inner Mongolia, the increasing potential yield of MengCQun, MengQun3, MengQun4and Zhongzong7is the highest, and the main agricultural characters of these four populations are better than the other study populations. Therefore, these four populations are the ideal material for selecting selfed lines and breeding hybrids, and able to use as the breeding material. Base on the SCA analysis, these12maize populations were partitioned into4hetarosis class populations, and only CQun2is belong to different hetarosis class group in these three areas.3.60hybrid populations were generated by test cross between these12maize populations and tested varieties. The higher values of SCA showed in the populations of Zhongzong7x Ye478, MengAQun x Mo17, MengBQun x B73, MengCQun*B73, MengQun4x B73, CQun x Huangzao4, CQun2x Huangzao4and Zhongzong5x B73. As the higher generic difference and frequency of good non-additive gene are showed in these8populations, they have the advantage to build up hetarosis pattern.4. The results in the maize densification effect analysis showed that the planting density of MengAQun and MengQun4were suitable to be densified; MengQunl, MengQun, MengQun and Zhongzong7were able to be densified, but CQuanl, CQuan2, CQuan3, MengQun2, MengQun3and Zhongzong5were not suitable to be densified.5. The generic increment in yield is higher in the populations of MengQun2, MengQun4, Zhongzong7, MengAQun and MengCQun, furthermore, the improvement effect of the other agricultural characters were also significant. Thus, these five maize populations have the advantage in directly selecting first-class plants for self cross. The generic increment of the other seven populations was small, and the potential improvement of these populations was very limited.6. The results in the investigation of DNA sampling from maize populations indicated that the best DNA sampling method was to sample60-plants from each maize group, and divide five sub-populations with12-plants per sub-group, then extract DNA sample from mixing leaves in each sub-group.7.391polymorphic bands were gained by amplifying genome DNA from the studied12maize populations and6CK self cross maize populations using86selected primers. There are2-11genes in each locus, average is5.67. The value of GD of these18maize populations is ranged from0.268to0.807with0.528for the average, thus, the hereditary basis of maize populations is wide. The studied12maize populations and6CK self cross maize populations could be partitioned into6class group on the basis of0.67for the GD value.