Studies On The Oppositifolious Maize's Karyotype And Isozyme And Genetical Behavior Of The Oppositifolious Character

Oppositifolious character of maize is a new variation type, whose leaf and kernel are both oppositifolious, which is a high-yield breeding germplasm resource. The experiment has been carried out with sis-group oppositifolious and alternate sister-lines through oppositifolious character transfering, initially analysed their differences in chromosomal karyotype, and biochemically studied their peroxidase, catalase, polyphenoloxidase and superoxide dismutase isozymes. The paper has also studied the genetical selection and combination effect of oppositifolious character. The results are as follows:1.Chromosomal karyotype analysis of the oppositifolious and alternate maizes has been carried out with the method of essential balm. It has been found initially that the oppositifolious maize has two pairs of satellites, while the alternate maize only has one pair of satellites. Besides a pair of satellites in the short arms of 6th chromosomes, another pair of satellites are mainly in the short arms of 10th chromosome. At the same time, the size and morphology of the second pair of satellites are different with satellites in the 6th chromosomes. Differences in chromosomal karyotype of the oppositifolious and alternate maizes can provide good references to the oppositifolious maizes in cytogenetic study. However, whether the differences are caused by chromosomal structural variation or gene expression form, it will need a further query. 2.Through observing meiosis prophaseⅠof pollen mother cell of oppositifolious and alternate maizes, it has been found that in oppositifolious maizes bi-nucleolus is existing in zygonema and pachynema and two pairs of chromosomes are connected with the nucleolus in diakinesis, which is not found in alternate maizes. This phenomenon probably has an inner link with oppositifolious maizes having two pairs of satellites.3.Five preparatory treatments in the chromosomal technique of maize are carried out. The result shows that 1.25μl/ml essential balm solution has the best effect. In the experiment, the comparison of the modified F-BSG method and essential balm method has been done. As far as the maize chromosomes are concerned, the effect of the essential balm method is better than that of the modified F-BSG method. This chromosomal technique may provide a consult for other plant chromosomal preparation.4.Through analyzing the spectrum of four isozymes (peroxidase, catalase, polyphenoloxidase, superoxide dismutase) of the oppositifolious and alternate sister-lines, it can be found that the polymorphism level of four isozymic bands is higher. The oppositifolious and alternate sister-lines all have the same band which belongs to strong and wide band in four isozymes. From the four isozymic bands, some specific bands can be seen in the oppositifolious self-lines. Because the oppositifolious and alternate maizes in this experiment are near isogenic lines(NILS), the specific bands of oppositifolious maizes in the isozyme maybe arise from the expression of oppositifolious character genes. 5.By continuously orientational selection, the oppositifolious frequencies of the most oppositifolious offsprings are increasing as selective generations are growing, till they are genetically stable. So continuously orientational selection is an effective technical way for obtaining stable oppositifolious lines. When the oppositifolious character is in different genetic background, the process and efficiency of the orientational selection is different.6.Full-oppositifolious F1 hybrid breeding can be carried out by three combination modes such as oppositifolious×oppositifolious,oppositifolious×alternate(alternate×oppositifolious), alternate×alternate. Different combination modes have different effects on the breeding of F1 full-oppositifolious combination.As far as oppositifolious frequency is concerned, oppositifolious×oppositifolious is the highest and oppositifolious×alternate(alternate×oppositifolious) is higher than alternate×alternate. In the view of F1 heterosis, alternate×alternate is...