Quantitative Trait Loci Of Oil And Main Fatty Acid Components In Soybean

Soybean [Glycin Max （L.） Merr.] is the most important oil crop in the world. The quality and use ofsoybean oil depend on oil content and the proportion of fatty acid. In order to meet the edible andindustrial demand, the improvement of fatty acid is the focus of soybean breeding. BC2families weredeveloped by Zhonghuang13（recurrent parent） and Zhonghuang20, Dongshan69（unrecurrent parent）.In this study, the families were genotyped by SSR molecular marker analysis, the oil and fatty acidcontents were analyzed by near infrared analyzer and gas chromatography. The objective of the study: toillustrate the difference of agronomic and quality traits and to discover the QTL related with oil andfatty acid. This can provide the guidance for molecular marker-assisted breeding in soybean. The mainresults were as follows:1. Statistical analysis of quality and agronomic traitsThere are statistical differences in protein, oil, fatty acids content and agronomic traits amongZhonghuang13, Zhonghuang20and Dongshan69, especially in the content of protein, oil, oleic acidcontent and plant height. There are rich variations and transgressive segregations on quality traits inZhonghuang13×Zhonghuang20（ZZ） population and Zhonghuang13×Dongshan69（ZD） population. Thecontent of oleic is the most variance wide range and the biggest coefficient of variance. There are alsorich variations and transgressive segregations on agronomic traits.The significant differences among lines, years and interection of both on all the quality traitsindicate the traits are quantitative traits controlled by many genes and environments in both backcrosspopulations. The significant difference of fatty acid among years is linolenic acid, linolic acid, oleic acidand saturated fatty acid. All the agronomic traits exist significant differences in lines and years.2. Correlation analysis of quality and agronomic traitsOil content had significant negative correlation with protein and stearic acid content. Stearic acidcontent had extremely significant negative correlation with oleic acid content and positive correlationwith linolenic acid. Oleic acid content had extremely significant negative correlation with linolic acidand linolenic acid, linolic acid had extremely significant negative correlation with linolenic acid. Plantheight had extremely significant positive correlation with numbers of branches, nodes of main stem,pods per plant. Lowest pod height had extremely significant positive correlation with nodes of mainstem. Numbers of branches had extremely significant positive correlation with pods per plant. Hundredseed weight had extremely significant negative correlation with numbers of branches and pods per plant.Oil content had significant negative correlation with hundred seed weight. Stearic acid content hadsignificant positive correlation with plant height, lowest pod height and nodes of main stem. Oleic acidcontent had significant negative correlation with lowest pod height and nodes of main stem. Linolic acidand linolenic acid content had significant positive correlation with lowest pod height.3. Detection of population genotype by SSR markers and construction of genetic linkage mapThe study detected the ZZ population genotypes by SSR markers. A soybean linkage map with a total length of2285.3cM and the average genetic distance of15.0cM was constructed using151polymorphism SSR molecular markers, covering the20linkage groups of soybean. This is the firstlinkage map of Zhonghuang20. The distance of adjacent markers is1.36cM to72.69cM, the length oflinkage group is26.84cM to280.72cM, the number of markers within one linkage group is3to12.Another soybean linkage map was contructed with using138polymorphism SSR molecularmarkers. The total length of the map is2285.3cM, and the average genetic distance of the map is15.0cM. The distance of adjacent markers is1.03cM to87.22cM, the length of linkage group is37.88cMto386.56cM, the number of markers within one linkage group is3to14.4. using two methods and two populations to map QTL related with oil and fatty acids73and59QTLs were identified associated with soybean oil and fatty acid by single markeranalysis （SMA） and inclusive composite interval mapping （ICIM） in three years in ZZ population andZD population, respectively.Marker sat₃67is positioned associated with palmitic acid in different years and different methods,the phenotypic variation efficiency is23.88%³9.66%. This indicating marker sat₃67for palmiticacid is stably inherited and efficient QTL. Marker satt397is detected with oleic acid, linolic acid andlinolenic acid, and marker satt079is detected with oil, stearic acid, oleic acid, and linolic acid, theseQTLs may control the synthesis and metabolism of several fatty acid components. Marker satt202,satt397are detected with oleic acid, linolic acid in both SMA and ICIM, indicating that these are thehigh credibility QTLs. This could be useful in molecular marker-assisted breeding. Marker satt327,satt179are related with oil content in this study, which were reported in previous researchs. It indicatesthat these two markers are not affected by the genetic background. Marker satt079is detected in bothpopulations related with oil and several fatty acid components, and the marker were not reported inpublished articles, this is an important and newly detected marker.