Study On Factors Influencing Penetrance Of Multi-Ovary Wheat And Its SSR Molecuar Marker

Heterosis is universally present in the nature. Wheat, an important crop in the world, is conferred with observable heterosis, and taking use of its heterosis is an important way to enhance wheat output. The research on wheat heterosis has made great advance in recent years, but it is still difficult to extend hybrid wheat in a larger area because of some problems which haven't been overcome like renewal and development of superiority combination and especially study and establishment of effective seed production technology. Wheat is self-pollination crop with great sowing amount and low propagation coefficient, hence production of large number of hybrid seeds effectively and economically is crucial for production of hybrid wheat in a large scale.wheat with multi-ovary is new found peculiar germplasm source, featured with three stamens and more pistils amounting to 2-3. It has the advantage of stable seed-setting and multiple grain leading to the improvement of propagation coefficient. In order to improve propagation coefficient and cut seed production cost, this study employed mixed population separation methods, and conducted was SSR marker location of multi-ovary gene and the systematic research on expression effects of penetrance.1. Penetrance at the maturing stage was determined adopted multi-ovary wheat with different types of aegilops cytoplasm including homogenous homonuclear, homogenous allonucleus, heterogeneous homonuclear as materials, and dps7.05 software was used to conduct variance analysis. The results showed that: (1) Soil water, fertilization level and other condition could not play a dominant role in the multi-ovary development. (2) Under the same nucleus background, cytoplasm kept independent and stable in multi-ovary development and formation, and had no influence on penetrance. (3)Penetrance was closely related with nuclear gene. In heterogeneous multi-ovary wheat, the penetrance was insignificantly influenced by the interaction of nucleus and alien cytoplasm, and mainly determined by nuclear genome.2.Using BSA method,a dominant multi-ovary line of common wheat(Triticum aestivum)was crossed with variety Xinong 1376(T.aestivum).From F₂ segregation population and BC₁ Population ,a multi-ovary and a single-ovary gene pools were established; via SSR-PCR method, single-ovary and multi-ovary mixed populations were screened using 30 primers. The result indicated that the expanded product of one primers on 6B showed specific character among neaisogenic lines, multi-ovary population han two bands , single-ovary population han one band. After repeating tests and checking up individual plant, only primer WMC494 showed the stable multi-morphological character to F2 and BC1mixed population and single plant,so it could be used as a molecule marker of the dominant multi-ovary gene.3. When near isogenic pool of relative character was established by means of BSA, the number of plants in mixed population should be appropriate.If the gene pool contained a small number of plants, random error caused by sampling increased the possibilities of difference of DNA amount between two pools, and false-positivity would be observed; if the gene pool contained a large number of plants, the number of neighboring chromosomes of targeted gene would decrease because of the increasing exchange, making it difficult to detect polymorphic spots. Therefore, it was necessary to select 10-20 plants.