Breeding Of Transgenic Indica Rice Resistance To Disease,Insect And Herbicide

Rice is one of the most important cereal crops in the word,and the production security is an essential ingredient for providing stable food.However,the productivity has been affected dramatically by several factors,including plant diseases,insect pests and weeds.In that case,the ideal rice varieties with high yield,good quality and multi resistance are required.Owing to the development of genetic engineering technology,rice varieties with improved insect and diseases resistance can be achived.These transgenic rice varieties can not only meet the requirements of production but also reduce the use of chemical pesticides which brings economic benefit and maintains the ecological equilibrium.In previous studies,sever resistance genes,including ferredoxin-like amphipathic protein(APl),the Bacillus thuringiensis cryIA(c)gene(Bt),galanthus nivals agglutinin(GNA),bialaphos resistance(Bar)have been introduced into a japonica rice variety mediated with Agrobacterium.We introduced these genes into three elite indiica rice varieties by using the method of backcrossing.And then multiple resistance rice lines with different genes were selected.The resistance of these lines to bacterial blight,sheath blight,herbicides and stem borers were evaluated.The results are as follows:1.Homozygous transgenic lines selection:Four genes,including API,Bt,GNA and Bar were introduced into three indica rice varieties,9311,?-32 and Zhonghui 8006 by using cross between these varieties and the japonica lines harboring the target genes.Four homozygous transgenic lines,9311(API),9311(GNA and Bar),11-32(Bt)and Zhonghui 8006(APl,Bt,GNA and Bar)were selected after more than 6 generation backcross and one generation self-cross.2.The results of RT-PCR analysis implied that these genes express normally in the three indica rice varieties.3.Improved resistance of the transgenic lines to disease,insect pests and herbicide:The resistance level of transgenic lines harboring API to bacterial leaf blight was improved significantly compared to that of the control.The lesion lengths of the transgenic lines are less than 3 cm,which are shorter than that of the wild type.In a natural field condition without any insecticide applied,all the transgenic rice plants were found to be not injured by the rice leaf folder,whereas the wild types were impaired seriously.Rolled leaf rate of 2 lines harboring Bt gene are 3.7%and 2.3%.Dead ear rates of these 2 lines are 0.They are lower significantly than wild types.Rolled leaf rates are,100%for II-32 and Zhonghui 8006;Dead ear rates of ?-32 and Zhonghui 8006 are 1.7%and 1%,respectively.Those results indicat that the resistance of the transgenic indica rice harboring Bt to rice leaf folder and rice stem borer are improved.The transgenic lines harboring Bar showed resistance to Basta.4.Most of the agronomic traits of the transgenic rice are comparable to the wild type.There was no significant difference in agronomic traits between the three transgenic lines harboring AP1 or Bt and their parent varieties.In a similar,most of the agronomic traits of the transgenic line harboring AP1,Bt,GNA and Bar resemble wild type Zhonghui 8006 but with a higher seed setting rate.