Meiosis And D Genomes Sequence Variation In Amphidiploid From Triticum Aestivum L. And Secale Cereale L.

Wheat (Triticum aestivum L.) is one of the most important food crops. With the development of agricultural production and improving of people's living standards, higher requirements have been put forward about quality and resistance of wheat.However, under the long-term cultivation, the genetic diversity is losing gradually, genetic basis is narrowing, resistance is decreasing. Hybridization is an important way to improve crop varieties, and the common method to study affinity relationship between species, phylogenetic and evolutionary degree. Therefore, it is critial to induce some excellent genes from relatives of common wheat into the wheat to broaden the genetic basic of wheat. Distant hybridization is an important way to improve crop varieties.Rye (Secale cereale L.) is one of the earliest and most successfully submarginal plants used in the species improvement in wheat breeding programs. There were many advantageous genes in rye chromosome can be used to improve wheat, such as yield genes, stress tolerance genes, disease resistance genes and insect resistance genes,The wheat X rye Amphidiploid plays a key role in this process just as a bridge. Hence, in the present study, we focus on the chromosome behavior changes in the wheat X rye amphidiploid plants.In this study, we got wheat cultivar 'Chinese Spring' and 'Mian yang11' crossed with diploid rye'AR106BONE','Kustro', 'Jing zhou' and 'S.Vavilovii' respectively, and obtain Chinese Spring×AR106BONE(CA), Chinese Spring X Jing zhou(CJ), Mian yang11×AR106BONE(MA), Mian yangll×Kustro(MK) and Mian yangll×S.vavilovii (MV)double diploid materials. The first and the second generation self-intercross plants after chromosome doubling were used as matierals to analysis the chromosome structure, while the analysis of the D genome sequence changes by molecular cytogenetical methods. The results were as follows:1. Abnormal behavior of rye chromosome in wheat X rye amphidiploid pollen mother cells during meiosis. (1)At metaphase I, there are massive rye univalentsand and a few wheat univalents. All materials, except CA4-5-1, showed more rod bivalents than ring bivalents. In addition, a small amount of rye trivalents and quadrivalent were observed. Particularly, in some materials, low-frequency chromosome translocation between wheat and rye was observed; (2)At anaphase I, the meiosis asynchrony in rye chromosomes,or fragments. sometimes,that is, chromosomes in other plant are all lagged behind the rye chromosomes and fragments sometimes in lagged plant chromosomes; (3)At telephase I, the chromosome multipolar polymorphism fission phenomenon was observed. there were chromosome lagged behind and chromosome bridge in rye with different numbers,also the micronucleus; (4)At telephaseⅡ, two cells asynchrony and the phenomena of rye chromosome lagged behind were also obseved; (5)There were micronuclei with different size and nembers in the tetrad stage.2.Unbalanced segregation of chromosomes during meiosis in wheat X rye amphidiploid pollen mother cellsIn this research, unbalanced segregation phenomenon of rye chromosomes were found in the four combinations, and the fission pattern is varied. Specially, in plant MV6-1-3, the number of rye chromosomes which carried over the two-pole was consistent, while the wheat chromosomes were inconsistentand, that is 20 and 22, respectively. Unbalanced segregation of chromosomes would change the number of chromosome in the offsping cells. In the pollen mother cells of plant MK25-3-2, the rye chromosome's number was mostly 15. It wasn't regularly seen, and further approved the phenomenon of sepration of unequal meiotic.3.Low-frequency chromosome translocation in wheat X rye amphidiploidThe phenomena of chromosomes translocation was found almost in all materials except in plant MK19-4, MV6-1, CA4-5-1 and CJ2-1-6. There were end translocation, whole arm translocation and small fragments translocation. The translocation ratio in plant CA5-2-3 were higher than others. It was 7.143% in the 84 cells during metaphase I, which was few in correlative studies.4.D genomes change in wheat X rye amphidiploidSix EST-SSR primers specific to wheat D genome were selected randomly to detect the D genome change in F1, S1, S2 plants.The sequence results showed that the seqence of parent MY11 were lost in S2 plants. On the contrary, the results of genomic in situ hybridization showed that the chromosomes of D genome were prensent.In the paper, knowledges about chromosome meiotic of octoploid triticale were enriched. It provided some theoretical basis for plant allopolyploids and the application of octoploid triticale in wheat breeding.