| At present, the studies on rice genetic improvement are facing with two difficult problems, i.e. how to use hybrid vigor effectively and how to fix hybrid vigor via modern biotechnology. Previous research results have confirmed that polyploid rice possesses great potential value and autotetraploid rice may be the most important germplasm in the studies using polyploid rice to improve rice yield. Low-energy ion implantation is a new agent for mutation induction in plant. The application of ion implantation technique on autotetraploid rice varieties improvement has made much progress. In the present study, autotetraploid rice IR36-4X was treated with ion implantation technique by nitrogen ion beams and a polyembryonic seedling mutant (named as the IR36-Shuang) was identified in M2 generation. The bioeffects and residual action of ion implantation on the mutant were systematically investigated with an aim to explore the correlation between the phenotype of the mutant and the underlying mechanisms responsible for the induced mutation. This study may provide basic data for further studies on the application of ion implantation technique to rice breeding.Stabilized polyembryonic seedling mutant line was obtained after several generations' screening according to the line of descent screen method. The mutant line was systematically investigated about their major agronomic characters, location of seedling in polyembryonic seedling and the genetic development of polyembryonic seedling. The development process of female gametophyte and male gametophyte of the IR36-Shuang was observed by using a Laser Scanning Confocal Microscopy. Moreover, the process and characters of its double fertilization, embryo and endosperm development were also studied by using the same means. At the same time, the cytological initiation of the additional embryo in the IR36-Shuang was observed and determined. The results are as follows:...
|
PDF Full Text Request