Abstract:

Some alien genes have been successfully introduced into wheat (Triticum aestivum L.) mediated by either biolistic particle or Agrobacterium since the first report on the transformation of this specie in 1993. The segregation regulation of transfer genes or their effects on some main agronomic characteristics have been also investigated in the self-crossing generation of transgenic plants by some researchers. However, the genetic role of introduced genes in the hybrid generations and the influence of same alien genes on the agronomic traits of different wheat cultivars have been studied seldom. It is very important to answer the above questions for the biosafty releasing of genetic modified wheat in the future. GUS reporter gene and nptⅡ selection gene were transferred into three wheat genotypes of PM97034, Bobwhite, and Xinchun 9 by Agrobacterium–mediated transformation in our previous study, and homozygous transgenic lines were further obtained. A homozygous transgenic line derived from Xingchun 9 was used to be crossed with its wild type and genetic analysis of the two foreign genes were carried out in F₁ and F₂ generations by employing PCR, ELISA, and X-Gluc staining. All F₁ plants were confirmed to be positive by the three tests, and it indicated that the alien genes appeared dominant in F₁ generation, and no gene lost or silence happened. 107 F₂ plants were tested by PCR for nptⅡ gene, in which 78 plants were demonstrated to be positive and other 27 plants to be negative. Seventy-five F₂ plants were tested by X-Gluc staining for GUS gene, in which 54 plants were demonstrated to be positive and other 21 plants to be negative. These results suggested that the segregated ratio of the alien genes in F₂ generation was 2.6:1, being consistent with Mendelian inheritance of 3:1, and lost or silence of the foreign genes wasn’t found in this generation, either. Fourteen T₄ homozygous transgenic lines, among which 7 were derived from PM97034, 3 from Bobwhite, and 4 from Xinchun 9, were planted in field by random arrangement and 3 reduplications, in which three wild type varieties of PM97034, Bobwhite and Xinchun 9 were used as controls, and each material was planted for 5 rows by 3 meters in length. After PCR confirming at seedling stage, seven agronomic characteristics including growth duration, fertility, plant height, spike length, grains per spike, grain weight, were 1000-grain weight were examined by taking 10 plants from each trial, and all collected data were analyzed by DPS computer software for variance difference. The results revealed that the inserting of the alien genes frequently changed plant height and growth period of wheat acceptors, and other main agronomic traits were not affected by the transferring genes obviously.

Key words: Wheat (Triticum aestivum L.), Transgenic wheat line, Agronomic characteristic, Genetic analysis