Analysis By QTL For Protein And OIL Content Of Soybean Seed

Protein and oil content are the two main factors what decide the quality of soybean seed. This research based on the previous research what had mapped 3 QTL for protein and 4 QTL for oil content by a small sample of RIL population. It target the maker interval which the 7 QTL located at to map QTL for the same traits precisely by a large sample of RIL segregating population as of the previous research, and to analysis the genetic characters of the two traitsat the same time. The result is following:(1)3 QIL for protein content and 4 QIL for oil content were detected. They located at the maker interval of Satt225-Satt599, Sattl87-Sat₁29, Satt070-Satt063, and Sattl00-Satt557 in linkage group Al, A2, B2 and C2 of DNA maker genetic linkage map of soybean.(2) One QIL for protein content and one for oil content is only l.01cM and 0.49cM far from the nearest maker of each. The two QTL are the targets for map-based cloning related genes. Because Satt632 was mapped into the interval of Sattl87-Sat₁29, a QIL had been located at the interval by previous research was identified to be two QIL which distribute in line tightly.(3) This research has summarized the genetic characters for the traits of protein content and oil content. First, through integrated all 7 QIL into the integrated linkage map of soybean and compared to knew QIL had been mapped on it, 5 QTL of this research is no more than 5.5cM distant to the knew QIL or QTL clusters. Confirm to most researches, QIL of this research show being cluster to be distributed in genome. It is common that there are gene clusters in genome of plant, which is constituted by several genes have the same function. That is may be the best explaining for the existence of QIL cluster of this research.(4) The negative correlation between two traits of protein content and oil content for soybean seed was analyzed in this research. The research has detected a QIL on linkage group B2 what increase the protein content and decrease the oil content of soybean seed at the sametime. Its value of additive effect for protein content and oil content is 0.3812 and -0.2118. As the result of this research, the existence of pleiotropic gene may be the best explaining for the negative correlation. This supposition is also applied by other researches.(5) According to the newest integrated genetic linkage map of soybean (http://bldg6.arsusda.gov/^pooley/soy/cregan/soymap.htm), this research constructed a saturated part linkage map for the interval which 7 QTL located at. This map is 77.14cM summary long distance. It contains 71 loci, which include 63 DNA maker, 1 classical maker and 7 QTL. There are 38 SSR of the DNA makers. So, it would be the most important basic for map-based cloning related gene by SSR maker.