| Triploid and tetraploid derived from twin-seedling populations crossed with some common diploid, and some stable progenies were obtained in second filial generation in Rice Research Institute of Sichuan Agricultural University. For years researches indicate, this kind of early generation stable phenomenon only present on filial generation involving polyploid. Whereas in early generation of hybrid of diploid corresponding the polyploid in two-seedling that cross with common diploid, this kind of specific phenomenon never appeared by now. In this study, we contrast and analyse five couple of plants of 3N and 2N respectively derived from twin- seedling with SSR, in order to ascertain if gene(s) or factor(s) prompting early generation stability was produced in the genome of 3N in the course of twin-embryo, and analyse further combined with the stability of filial generation of 3N and 2N plants. The main results are following:(1) Five pairs of 3N-2N twin-seedling were analysed by SSR, And polymorphism doesnot present at 425 primers loci. So the result is conferred that there are not difference in DNA sequence on 3N and 2N plants of twin-seedling. The differences of phenotype and behavior between them may be resulted from polyploidization and dosage effects. For contrastive method was singleness, further research were needed.(2) 3N plants from twin-seedling act as female parent, crossed with common diploid as male, 267 F| hybrid seeds were obtained. Percentage of seed setting from all combinations was about 0.7%. And by tube culture, 52 seeds of FI germinated. All seedlings were planted in field in 2001. The most were died and nine FI hybrid survived. All of them were aneuploid and only five plants were partial fruiting. The seeds from each panicle of these FI hybrids were harvested respectively. At the same time, Ft hybrids of 2N×2N were planted in field and revealed normal phenotype. Their FI populations appeared segregation and no stable populations appeared. It was maybe direct reason that there weren'tdiploid plants in FI populations of 3N×2N. The statistics analysis revealed that F2 populations of 3N×2N were more segregative than that of 2N×2N. And many new characters were produced in the F2 populations of 3N×2N, that were valuable to further research.(3) We used SSR to analyse the relation among parentsx FI and F2 of combinations 3N×2N. The results revealed FI plants presented heterozygous bands at all of primers loci that produced polymorphism between the parents. That is, F1 plants of 3N×2N possess genetic material of not only maternity but paternity, and are true hybrid. F2 populations also presented normal segregation.(4)The SSR analysis for one of F3 population from the cross of 149(3N) × R527(2N) revealed the bands of F3 plants was uniform or almost uniform at 12 of 19 primers loci that produced polymorphic bands between the parents. Only at 7 primers loci, F3 population presented normal segregation. This abnormal phenomenon maybe result from that the genome occurred special gene rearrange that made available gene(s) to be early homozygous and rapidly inherit.
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