Transbreeding Of Wheat Glutenin Subunits Nils And Study On Its Technology System

Compositions of wheat glutenin subunits are closely related to wheat processing quality.It is very important for wheat quality improvement to identify compositions of wheat gluteninsubunits. Therefore, studying on the quality effect of HMW-GS is beneficial to discover thegenetic potential and improve the processing quality of wheat. But, present research resultswere not clear due to the interference of different genetic backgrounds and some other factors.Studying on the quality effects of HMW-GS with NILs can eliminate the interference causedby different genetic background and make the results more accurate and credible. Therefore,the breeding of NILs has become the precondition of relevant study, but the breeding requiresconsective backcross and tracking detection cost a longer period. So the optimizingidentification of subunits would accelerate the breeding dramatically. This study is just basedon the conditon mentioned above. Firstly, a method based on using four differentconcentrations of separation gel of SDS-PAGE and molecular markers on AxNull, Bx7, Bx7OEand By8, was developed and validated by18check cultivars with known HMW-GS. Theidentifying results of check cultivars were consistent with their known HMW-GS. Secondly,combining plant in the field and greenhouse, and using the developed method to detect thetarget subunits and their genes in backcross progeny can make the breeding more efficient andreliable. This study has obtained HMW-GS NILs with above method, and some obtainedcopies have been preliminary identified. Meanwhile, based on combining plant in the fieldand greenhouse as well as screening molecular markers to track the target LMW-GS genes inbackcross progeny, a fast technology system for LMW-GS NILs transbreeding has beendeveloped.The main results of this study:1. SDS-PAGE with9%separation gel and molecular markers (AxNull, Bx7, Bx7OEandBy8) can identify the composition of hybrids HMW-GS accurately and rapidly.2. Using developed molecular markers on Glu-A3and Glu-B3loci and DNA extractedfrom young sprout period wheat, a system for the detection of LMW-GS genes in youngsprout period of backcross populations was established after optimizing the PCR systemsfrom PCR composition, amplication conditions and electhrophoretic contitons. 3. The HMW-GS of the harvested backcross populations was detected with SDS-PAGEin the lab, and the seeds with target subunits accoring to the detection results weretransplanted to the greenhouse after seed vernalizaton of25days. Then the HMW-GS genes(AxNull, Bx7, Bx7OEand By8) and LMW-GS genes were detected at the young sprout periodof wheat. And the detecton with SDS-PAGE will be repeated in the lab after harvesting themature seeds from the greenhouse and then selected seeds will be planted in the filed. Thesame HMW-GS and LMW-GS genes detection (as in the greenhouse) will be completed in thefiled at the young sprout period. Finlally, the transbreeding will complete two generationswithin one year.4.Through the transbreeding methods mentioned above,21copies were obtained in fivedifferent genetic backgrounds with high backcross generations HMW-GS strains. Two ofthem were in the genetic background of Xiaoyan6; five of them were in the background ofXianyan22, six of them were in the background of Xinong2208, four of them were in thebackground of Xinong1718, and four of them were in the background of Huayu8. Then thereceived NILs were evaluated preliminarily. The results showed that different target subunits,little differences of the agronomic traits, and the same composition of other HMW-GS,LMW-GS and gliadin were found in different materials with the same genetic background,which indicated that the transbreeding is worked.5. There are104BC3F1NILs of LMW-GS obtained, including31lines in the geneticbackground of Xiaoyan22;37lines in the genetic background of Zhoumai22; and36lines inthe genetic background of Zhoumai23.In this study, the effective methods of detecting the composition of hybrids HMW-GSand the target LMW-GS genes in backcross progeny were founded. Popular winter wheatwere used as the recurrent parent to establish several NILs groups with different geneticbackground, which is the first time to study on the NILs of Chinese winter wheat, layingfoundation for accurate analyzing subunits quality basic materials.