Detection Of Soybean Protein Content,Oil Content And Fatty Acid Content QTL With Backcross Introgression Lines

Soybean[Glycine max（L.）Merrill]contains about 40%protein and 20%oil,it’s an important source of vegetable protein and edible vegetable oil.in the world.In order to meet the growing demand for soybean oil,the breeding of soybean varieties with high protein content,high oil content and fatty acid composition is the focus of scientists.In order to provide basis for soybean quality breeding,the BC₂F₅ and BC₂F₆ populations of Zhonghuang 13×Dongshan 69 and Zhonghuang 13×Zhonghuang 20were used as materials,SSR molecular markers were used to analyze the genetic diversity of the populations,and the contents of protein,oil and fatty acids in BC₂F₅ and BC₂F₆ were determined by near infrared spectroscopy and gas chromatography.The QTLs of protein content,oil content and fatty acid content were determined by the methods of inclusive composite interval mapping and single marker analysis.The main results were as follows:1 Analysis of phenotypic traits in the backcross populationsThere were some differences in agronomic and quality characters among Zhonghuang 13,Dongshan 69 and Zhonghuang 20.The plant height,the number of main stem nodes,numbers of branches and pods per plant of Zhonghuang 13 were lower than those of the donor parent Dongshan 69and Zhonghuang 20,while the lowest pod height was higher than that of the donor parent.The content of protein and stearic acid were higher than those of donor parent,while the oil content was lower than that of donor parent.Among them,the plant height,pod number per plant,protein content,oil content and oleic acid content were largely different.In agronomic traits,the coefficient of variation of numbers of branches was the largest,and the coefficient of variation of linolenic acid content was the largest in quality traits.There were abundant genetic variation and different degree of super parent segregation in two populations.Interactions between line and year,there were significant differences about plant height,numbers of branches,pods per plant and hundred seed weight in the population of Zhonghuang 13×Dongshan 69,while all the agronomic traits had extremely significant differences in the Zhonghuang 13×Zhonghuang20.Interactions between line and year,there were extremely significant differences in seven main quality characters of the two populations.In the years,there were significant differences in protein and oil content of the two populations,the five kinds of fatty acid content had significant differences in the Zhonghuang 13×Dongshan 69,while there were extremely significant differences about stearic acid content,linoleic acid content and linolenic acid content in the Zhonghuang 13×Dongshan 69.There was a extremely significant negative correlation between protein content and oil content.The oil content had significant negative correlation with linolenic acid content.The palmitic acid content had extremely significant positive correlation with stearic acid content,linoleic acid content and linolenic acid content,while had extremely significant negative correlation with oleic acid content.Stearic acid content had extremely significant negative correlation with linoleic acid content.Oleic acid content had extremely significant negative correlation with linoleic acid content and linolenic acid content.The nodes of main stem and hundred seed weight all had extremely significant negative correlation with the linolenic acid content.The nodes of main stem also had extremely significant positive correlation with linoleic acid content and had negative correlation with oleic acid content.2 Construction of genetic mapOne hundred and six polymorphic SSR markers for the analysis of Zhonghuang 13×Dongshan 69,a genetic linkage map including one hundred and six SSR markers,a total length of 534.63 cM,an average genetic distance of about 5.04 cM and covering the other seventeen linkage groups in addition to C1,A2 and B2.Among them,the number of markers on A1,B1 and H linkage groups was only two,and the number of markers on D1b linkage group was the largest,with a total of twelve markers.The distance between Sat₁47 and Satt220 on M linkage group and the distance between Sat₃13 and Satt516,Satt516 and Sat₂40 on F linkage group were the minimun,which was 0 cM.The maximum distance between Satt571 and Satt562 on I linkage group was 52.46 cM.One hundred and eight polymorphic SSR markers for the analysis of Zhonghuang 13×Zhonghuang20,a genetic linkage map including one hundred and eight SSR markers,a total length of 948.01 cM,an average genetic distance of about 8.78 cM and covering twenty linkage groups.Among them,the number of markers on A2 and N linkage groups was only two,and the number of markers on O linkage group was the largest,with a total of fifteen markers.The minimum distance between Satt579 and Satt290 on D1b linkage group was 1.02 cM.The maximum distance between Satt649 and Satt343 on F linkage group was 54.93 cM.3 Protein content,oil content and fatty acid content QTLUsing inclusive composite interval mapping and single marker analysis of the IciMapping 4.1software and combining two years of phenotypic data and two genetic linkage maps,fifty-seven and seventy-one QTLs were identified associated with soybean protein content,oil content and fatty acid content in the populations of Zhonghuang 13×Dongshan 69 and Zhonghuang 13×Zhonghuang 20,respectively.Satt445^Sat₃03 for oil content was detected in two years.Satt445^Sat₃03 and Satt543^Satt574 for protein content and oil content were detected in the same year.Sat₃89^Satt590,Satt238^Satt388 and Satt685^Sat₃81 for oil content were detected.Sat₃34^Sat₂62 was detected to be a new locus related to the palmitic acid content.Satt346^Satt210 was correlated with the content of stearic acid,the phenotypic contribution rate was up to 40.58%.Sat₃34^Sat₂62 was correlated with oleic acid content,the phenotypic contribution rate was 25.97%.QTL of the oleic acid content located on O linkage group was detected in the marker interval Satt173^Satt262,which was different from the only QTL of oleic acid content which was deteceted by other scientists in different regions,the marker interval may contain new loci associated with oleic acid content.The only QTL which may be related to linoleic acid content was found in the marker interval Satt244^Satt431 on the J linkage group.The phenotypic contribution rate was 29.31%.At present,there is no report on I and M linkage group about QTL of the linolenic acid content.In this study,four QTLs were located on the two linkage groups and the phenotypic contribution rates were 32.74%,35.43%,35.99%and 37.45%,respectively.