Distribution Of Dwarfing Genes Derived From Some Wheat Germplasms In Huang-Huai River Wheat Area And The Hederity Study On Dwarfing Gene Of Wheat Variety "Zhou 88114 AI"

Dwarfing and logging resistance is one of most important targets in wheat breeding. Dwarfing genes or dwarfing resources are the basic materials for dwarfing breeding. 26 dwarfing genes have been identified till now, but because of some known and unknown adverse genetic linkage, only few of them could really be utilized. Therefore, if we can realize the characteristic of wheat dwarfing gene distribution and utilization of dwarfing resources in different wheat regions, it can provide more useful information about wheat genetic resources for breeders and will be of guiding significance in the future breeding research and production. In this paper, distribution of Rht-B1b,Rht-D1b and Rht8 for 254 wheat lines from Huang-Huai wheat area was studied by means of molecular markers BFMR1,DFMR2 and Xgwm261. At the same time, the backcross population Chinese spring/Zhou 88114ai// Zhou 88114 ai was crossed to study the dwarfing genes of zhou88114ai by molecular markers and height separationof BC₁F₁ and BC₁F₂ population. The results are as follows:1. In the 254 lines, 84 ,171 and 178 lines were found to take Rht-B1b, Rht-D1b and Rht8 gene,respectively, they accounted for 33.07%, 67.3% and 70.1% of the total number, respectively, and the corresponding average height was 80.7cm, 78.5cm and 80.7cm. The number of lines only with Rht-B1b,Rht-D1b and Rht8 was 15,36 and 31, which accounted for 5.9%,14.2%and12.2%, respectively, and the corresponding average height was 83.8cm,80.1cm and 86.2cm. The number of lines with Rht-B1b and Rht-D1b accounted for 6.3%, and the average height was 73.7cm. Additive effect was found between Rht-B1b and Rht-B1b, and when the two genes existed in a variety, its plant height would be lower. The number of lines with Rht-D1b and Rht8 accounted for 46.9%, that with Rht-B1b and Rht8 for 20.9%, that with Rht-B1b, Rht-D1b and Rht8 for 9.8%, and 3.5% of all the lines took no any dwarfing gene. Therefore, most gerplasms from Huang-Huai wheat area took different kinds of dwarfing genes. By means of molecule detection and pedigree analysis, Rht-B1b originated from Zhengyin 4, Rht-D1b from Nonglin10, Shuiyuan86 and Huixianhong, and Rht8 from Caucasus, Mara and Afu. The results of molecular detection were almost accordant with that of pedigree analysis, and molecular markers is feasible to test dwarfing genes and to apply in assistant selection breeding.2. F₁ plant heights from the hybrids of Zhou88114ai and other seven parents with different plant height were crossed, and compared with the heights of the double parents and mid-parent, the F₁ plant heights had different results. The plant heights of Zhou88114ai×Chinese Spring and Zhou88114ai×Xinmai9 were obviously higher than that of their mid-parent values, that of Zhou88114ai×Yumai2,Zhou88114ai×Wenmai6,Zhou88114ai×Xinong02 and Zhou88114ai×Aibian1 were a little higher than that of their mid-parent values and that of Zhou88114ai×Yunong202 was a little lower than that of its mid-parent values. The F₁ plant heights of Zhou88114ai×Xinong02 and Zhou88114ai×Aibian1 were lower than that of Zhou88114ai, and that of other hybrids were higher than that of Zhou88114ai. These results showed that other dwarfing genes existed in the parents and the action modes among the dwarfing genes were very complex. Some difference was found between the plant heights of BC₁F₂ population from Zhou88114ai and Chinese Spring in water and 69.7cm in drought environment. The average height was 70.9cm in water environment, and in drought environment. Continuous distribution was found in the plant heights of the population, and this showed that different dwarfing genes existed in Zhou88114ai. The height distribution in water environment was not accorded with normal distribution, and that in drought environment was accorded with normal distribution.3. 210 of all the 632 primers were found polymorphous between the double parents, and 12 primers were found polymorphous between the DNA pools of higher plants and lower plants for BC₁F₁ population. The linkage analysis was performed by the program MAPMAKER 3. 0, and 4 unlinked SSR markers were removed.A total of 5 QTLs were detected, 2 for water environment and 3 for drought environment. Individual QTLs explained from 3.76% to 17.84% of the phenotypic variation. All QTLs explained 54.36% of the phenotypic variation. In the drought environment, on chromosome 4B, the QTL in the region Xgwm149-Xgwm495 was the explained largest phenotypic variation with 17.84%, and the QTL between Xwmc652-Xgwm6 was the explained minimum phenotypic variation with 3.76%.This showed that there was a major gene and minor gene on chromosome 4B. The QTL between Xgwm484-Xgdm005 on chromosome 2D could explain 7.51% of the phenotypic variation. In the water environment, the QTL on chromosome 4B could explain 16.86% of the phenotypic variation, and that on chromosome 2D could explain 8.39% of the phenotypic variation. The favorable alleles of all the QTLs were from Zhou88114ai.These QTLs should be useful in breeding dwarf and semi-dwarf cultivars and marker assisted selection programs for breeding.