Establishment And Adjustment Of RIL Population And Its Application To Map Construction, Mapping Genes Resistant To SMV And QTL Analysis Of Agronomic & Quality Traits In Soybeans

Establishment and Adjustment of RIL Population and Its Application to Map Construction, Mapping Genes Resistant to SMV and QTh Analysis of Agronomic & Quality Traits in Soybeans ABSTRACT: RIL (recombined inbred line) populations were very useful in plant breeding and genetic research. Using RIL populations, the more closed linkage could be found and the genetic map could be more saturated. Because a genotype was represented by a inbred line, rather than by an individual, the RIL population could be used to analyze several resistant genes in one experiment. This was beneficial to the research of SMV (soybean mosaic virus) which had more than one strains. Furthermore, as a kind of permanent population, the RIL population could be evaluated in many different environments. So the genetic component of variance and the interaction between QTL and environment could be estimated more accurately when the quantitative traits were studied. But RIL population had undergone several rounds of meiosis and natural selection during the inbreeding process, there was more opportunity for its segregation apart from that of theoretical population. So it抯 necessary to analyze the experimental population when it was used. In the present study, a RIL population was constructed and used to research the method of evaluation and adjustment of experimental population, map construction, and QTL analysis of agronomic and quality traits. 1. A RIL population was derived from the Glycine max (L.) Merr. parents 慿efeng I ?and 慛annong 1138-2? The population consisted of 206 inbred lines in which 201 lines were used. 2. In order to evaluate and adjust the RIL population, a method called Simulated Population Sampling Criteria (SPSC) was proposed. A program which could be used to simulate and analyze RIL population was written. Through the test of equilibrium, symmetry and representation of SPSC, experimental population was found to be apart from theoretical population and lean to 慿efeng I ? After adjustment, the population was changed from 201 to 184 families. 3. Using the data of RFLP, SSR, AFLP, and two morphologic traits, genetic maps were constructed. Compared with each other, the map used adjusted population and that used unadjusted population were different. So the former map was selected. The map consisted of 305 markers which covered 3017.9 cM and converged into 25 linkage groups. 4. Four strains (Sa~ Sc-S. NI N3) of SMV were used to screen the RIL population. The results showed that the resistance to each of the four strains was controlled by one pair of genes. Through linkage analysis, the four resistant genes were found to be linked and located on the linkage group N8-Dlb+W. The order and distance is Rsa?1.4cM -Rn3-l0.2cM -RnI-35.ScM -Rsc-8. RFLP markers A69 IT, K4771, LC5T were found to be linked to the resistant genes RnI and Rn3. 4 AUTRACT 5. Eleven traits of date of flower, date of maturity, plant height, knots of the stem, lodging, seed weight, yield, number of pods per knot, seed protein content, seed oil content and the sum of seed protein and oil content were studied. Th. genetic parameters and correlation coefficients of the II traits were calculated. The results showed that the II traits had significant differences among families and most of correlations were significant. 6. By means of composite interval mapping, date of flower, date of maturity, plant height, knots of the stem, lodging, seed weight, yield, number of pods per knot, seed protein c...