| Disease-resistant varieties of wheat breeding has been the unremitting pursuit ofbreeders，but as the changing of physiological pathogenic bacteria，many resistance genesstart to lose resistance. Cultivating and promoting a wheat cultivar who contains a variety ofresistance genes as well as the adult plant resistance genes has received much attention ofmore and more breeders. To deeply comprehend the gene heredity rule of wheat diseaseresistance and improve wheat agronomic characters，we used far kinship wheat cultivarsxinong979and RL6077as parents to establish the BC1F1（655plants）and F2（691plants）descendant populations. With the tag csGS、WMS533and WMC44to detected the Lr68、Sr2/Yr30and Lr46/Yr29/Pm39genes respectively，the analysis of genetic characteristic of theresistance genes was carried out. Combined with the main agronomic traits，we could deeplycomprehend the gene heredity rule of wheat disease resistance genes and the correlation withagronomic traits. We also used SSR markers to evaluate the background response rates of92plants in the BC1F1population who have three kinds of resistance genes（Lr68+Sr2/Yr30+Lr46/Yr29/Pm39）at the same time. The main results were as follows:1.There were difference of the distribution and transfer rate of the three kinds ofresistance genes in the two descend populations. The distribution of each gene in twopopulations both was Lr46/Yr29/Pm39> Sr2/Yr30>Lr68. On the transfer rate, when singlegene transmitted in the F2population, the transfer rate of Lr68(65.41%) was lower thantheory, but the transfer rate of Lr46/Yr29/Pm39(75.83%) and Sr2/Yr30(74.53%) wasconsistent with the theoretical respectively. When double genes transmitted in the F2population, the transfer rate of combinations Lr68+Sr2/Yr30and Lr68+Lr46/Yr29/Pm39wereless than theory, Sr2/Yr30+Lr46/Yr29/Pm39was consistent with theory. In the BC1F1population, the transfer rate of Lr68(44.27%) was lower than theory, while the transfer rate ofLr46/Yr29/Pm39(56.64%) and Sr2/Yr30(55.11%) delivered higher than theory respectively. When double genes transmitted in the BC1F1population, combinations of Lr68+Sr2/Yr30andLr68+Lr46/Yr29/Pm39were consistent with theory, Sr2/Yr30+Lr46/Yr29/Pm39was higherthan theory. When three kinds genes transmitted at the same time of both populations, theywere consistent with theory. There may be linkage crossing over some genes.2. Three kinds of resistance genes had significant correlation with agronomic traits. Onthe agronomic characters, most of the indicators presented that the plants who containdisease-resistant genes were higher than those that not contain resistance genes. Thecorrelation between each kind of resistance genes and the several main agronomic traits wassignificant difference. All these three kinds of resistance genes were extremely significantpositive correlation with the plant height, spike length, spike-stalk and spike-internode. Andthey also correlated with other agronomic characters respectively at the same time. Each geneplayed a major role in the different agronomic traits, we could see they working independenceand coordination.3. By comparing the two descendant populations we knew that there were significantdifference between the BC1F1and F2populations. It existed not only on the distribution andtransfer rates of the resistance genes but also on the agronomic characters. On the severalmain agronomic characters，when the descendant plants of F2population tent to the donorparent RL6077, the descendant plants of BC1F1population tent to the recurrent parentxinong979. It also showed a regular that F2population was higher than BC1F1population onmany traits. Among them, the uniformity of backcross group is higher than the hybrid group.4. The background selection of the individual plants in BC1F1population was good. Theaverage genetic background response rates of the92plants who have three kinds of resistancegenes was75.09%. It was very closed to the theoretical value75%. The number of the plantswho’s genetic background response rates higher than80%was20. There were also2plantshigher than90%, and the highest one was up to91.67%. The genetic background responserates mainly between60%to85%, and the selection effect was not obvious. It indicated thatmarker-assisted selection has a good practicability in wheat breeding. At the same time, thecomparative result of the genetic background response rates of every chromosomes was A>total recovery rate>B>D, and D chromosomes presented significant difference with the others.On the correlation, only genomes A and D had significantly positive correlation. |
PDF Full Text Request