Identification of QTL Associated with Seed Protein and Sucrose Content in Two Soybean Populations.

Although most soybean [Glycine max (L.) Merr.] production in the U.S. is for animal consumption and industrial processes, there is a growing market for soy based food products directed at human consumption.  The sales of soy foods in the U.S. increased from $2.77 billion to $3.5 billion between 2000 and 2002, and sales are projected to grow annually at a rate of 10%-11% in the next ten years.  In general, desirable soybean varieties used to make soy foods such as tofu, soymilk, and edamame have the following characteristics; high protein content, large seed weight and size, acceptable seed coat and hilum color, high sugar content, and desirable seed texture.  The objectives of this research are to determine genomic regions, or quantitative trait loci (QTL), associated with protein and sucrose concentration in soybean seed.  The population ‘S97-1688’ x ‘PI243545’ was used for detection and mapping of sugar QTL, and the population ‘Hutcheson-RR’ x ‘R95-1705’ was used for detection and mapping of protein QTL.  Both populations were grown in 2007 and 2008 in a randomized complete block design with two replications and at two locations, including Fayetteville, AR and Stuttgart, AR.  Seed protein concentration was determined using near infrared (NIR) spectrophotometry and seed sucrose concentrations were determined by high-performance liquid chromatography (HPLC).  This research will facilitate an efficient breeding and selection process in the development of mid-south and U.S. adapted food grade soybean cultivars.