| Wheat is the largest food crop in the whole world, and it is meaningful to human life. Due to the global reduction of cultivated land area and population is increasing year by year, improving the grain yield is the task without delay. In recent years, transgenic plant technology is developing rapidly. It has been a preliminary application in wheat genetic improvement, which provides a new way for cultivating high yield varieties. Currently, the main receptor for the genetic transformation of wheat is embryo callus. Mature embryos are considered as the most convenient explants and can be used all around the year. There are some associations of quantity and quality between characteristics of wheat mature embryos and embryonic callus induction. So far, research reports are not found in the world. Meanwhile, wheat tiller is one of the important agronomic traits. It is important for breeding of the genetic improvement of wheat tillering characteristics. To explore the wheat mature embryo characteristic difference, 10 kinds of genotypes of wheat mature embryos were chosen and some of physiological and biochemical indices were measured. External and internal structures for mature embryos of 10 kinds of genotypes were observed. PvTB1 gene is cloned from bioenergy crop switchgrass and is related to tiller. At the same time, making the genetic modify of PvTB1 gene to wheat by particle bombardment, and the main results are as follows:1.Using the mature embryos of 10 different embryogenic callus as materials to explore differences between two types of wheat mature embryos characteristic. Biochemical tests which about soluble sugar, soluble protein, cellulose content and free amino acid showed that there were significant differences of soluble protein and cellulose content between two types of wheat mature embryos. The contents of soluble protein and cellulose in mature embryos of low embryonic callus rates were significantly higher than the ones in mature embryos of high embryonic callus rates. Other indices like contents of soluble sugar, free amino acid and glutathione had no significant difference between the two groups of mature embryos. Correlation analysis showed that the induction rates of embryonic callus had highly significant positive correlation(P=0.002,P<0.01)with cellulose contents, and significant negative correlation(P=0.01,P<0.05)with soluble protein content.2. Using the mature embryos of 10 different embryogenic callus as materials to observe the external morphology by stereomicroscope,there was a significant difference between the height of two types of wheat mature embryos. However in the observation of the internal structure through paraffin section method, no significant difference was found between the two types of wheat mature embryos.3. In this study, using SQ26, Xinong 928, Xinong 1376 and Zhengmai 9023 as explants, transforming PvTB1. There were a total of 409 resistant plantlets of wheat genetic transformation by resistance screening. After transplanting to the greenhouse, 350 were survived in these resistant plants. Finally through PCR identification, one positive plant was obtained in these resistant plants. The conversion efficiency was about 0.01%. In the dough stage, through statistical analyzing the 6 agronomic traits of positive plants and control plants including tiller number, spike length, stem length, flag leaf length, uppermost internode length and spikelet number surveys and photographic pillar. Comparing with control plants, there were no significant differences between them. It shows that PvTB1 has no expression or little expression in wheat. |
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