Genetic Study Of Derivatives From The Hybrids Of Chinese Spring Ph2b Mutant With Psathyrostachys Huashanica Keng

The diploid species of Psathyrostachys huashanica Keng is only in China and has many advantages, such as cold resistance, drought resistance, early, wheat stripe rust resistance, big anther and so on. In addition, it is easy to hybrid with common wheat. So this specie is a good parent for transferring alien chromosomal fragments by the way of wide hybridization breeding. The objective of this study was to detect the genetic of derivatives plants from the hybrids of Chinese Spring ph2b mutant with P. huashanica. The main results were described as follows:1. From the biological characteristics of S₁ and BC₁, it indicated that there were many variations in S₁ but the biological characteristics of BC₁ and common wheat were very like. So the fertility of selfing and backcross plants will be advanced with the high generation span and the backcross plants will be better, to some extent there were many differences among every plant.2. Cytogenetics study:(1) The somatic chromosome number of F₁×zhengmai-9023 and F₁×J-11 were both 49; But their, F₁×CS,F₁×CSph2b and S₁ were rang from47 to 49. Form that, it was clear that genome Ns was transferred into the common wheat successfully;(2) The average univalents of S₁, containing AABBDDNs genoms, had more than 7 at MI during meiosis. It indicated that at least one chromosome of the Ns genom derived from P. huashanica, caused asynapsis or desynapsis of one or more bivalents formed between homologues of the A, B or D genom. The average univalents of BC₁ plants both F₁×CS and F₁×CSph2b having less than 7, they may be promoted by ph2b gene which can cause chromosome pairing; But the average univalents of BC₁ plants including F₁×J-11 and F₁×zhengmai-9023 had normal number. On the whole, backcross plants could reinstate the action of ph2b quicker than selfmg plants. Thus, it is hoped to gain new materials from chromosomal rearrange.3. To analyze whether the descendants of S₁ and BC₁ have the alien chromosomal fragments of P. huashanica, the Ns genom specific primer OPW-05 was selected. All the plants, except No.4 and D, had the differential bands of P. huashanica.4. The specific bands of S₂ and BC₂ plants were indicated by storage protein.The results indicated that the Ns genom had been transferred into common wheat successfully and the chromosome had rearranged.