| The wheat as one of the most important crops worldwide is the staple food for35percent of the world’s population. Yield trait is always an important goal for wheat genetic and breeding improvement. However, it is difficult to achieve a substantial increase under the materials and methods we used before, although the yield of wheat has reached a very high level. Now, the combination of transgenic technique and distant hybridization methods provide an new approach that significantly improve the wheat production, which can transfer a series of useful exogenous genes into wheat to improve the yield trait of wheat. In this study, we had transferred maize C4high photosynthetic efficiency PEPC gene into wheat and made a cross between bread wheat and rye with big ear. Their offspring were analysed and selected using molecular and cytogenetic techniques. The results build a reliable materials and theoretical basis for wheat high yield breeding.1. Analysis the molecular characteristics and photosynthetic traits of a maize C4-high photosynthesis gene PEPC in wheat background.In this study, six positive T3transgenic lines, identified by PCR, and wild controls were analysed using Southern blot. The results showed that the PEPC was located different chromosome loci with1-3copies in six transgenic lines, in which two lines,1-27-3and1-51-4, integrated in Zhou19genome with single copy and in line17-1with2-3copies.We also used qRT-PCR and Western blot to analysis the expression of the six positive T3transgenic lines and two receptor controls. The results indicated that all the transgenic lines showed a higher expression of photosynthetic relative genes than controls, except line1-45-3. Lines1-27-3and5-32-2were increased4.7and5.8times compared with their controls meaning a significantly different at0.01level, respectively. So, the author inferred that the foreign PEPC had a corrected transcription and expression in wheat.The physiological and biochemical analysis of T3generation transgenic plants showed that enzyme activity and net photosynthetic rate has reached a significant level of four lines compared with the control, in which the PEPC activity and net photosynthetic rate maximum value for the of1.6μmol min-1mg-1and29.5μmol m-2s-1in heading stage, increasing1.6times and15.5%compared with the control. That mean photosynthetic characteristics of transgenic plants were significantly improvedFurthermore, we found the major yield characteristics of, such as plant weight, thousand grain weight and products per one plant, were improved significantly in transgenic wheat, especially in lines of1-27-3and5-32-2, which have the yield enhancive potential in wheat breeding.2. Molecular and Cytological Identification of of aNeW type of HexaPloid Triticale (Ian xiaohei).By couting the chromosome of root tip cell in progeny plants at Metaphase of Mitotic, we found that some of the aneuploid materials lost1-2rye chromosomes. While there were28chromosomes from common wheat and14chromosomes from rye in hexaploid materials (2n=42) resulting from situ hybridization analysis.The results of DNA molecular marker analysis to the genomes of variety Lan xiaohei showed that R genome group,14Rye chromosomes, had been conformed into Lan xiaohei, and the chromosomes of wheat D genome absented.The survey of agronomic traits showed that the tiller, spikelet number and grain number of Lan xiaohei were significantly improved than their male parent. They were also immune to Powdery mildew and stripe rust. However, the traits of plumpness and grain weight of were reduced. |
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