Pyramiding High Sucrose, Low Stachyose, and Low Phytate in Soybean Breeding Lines.

Soybeans are mainly grown for oil production and livestock feed. In the western cultures, human consumption of soyfoods has steadily increased in the past decades, expanding a dietary habit well practiced in Asia for centuries. Seed sucrose positively influences taste of the soyfoods, whereas stachyose and phytate are considered anti-nutritional factors due to their indigestibility problems, and chelating of other important nutrients in the case of phytate. The objective of this project was to combine high sucrose, low stachyose, and low phytate in soybean lines. An F₂-derived population of 143 individuals was developed from a cross between PI 200508 and V99-5089. Both parents are low in stachyose, while V99-5089 is also low in phytate but high in sucrose. Sucrose, stachyose, and phytate content were determined at F₂ and F_2:5 generations. F_2:5 lines were grown in Fayetteville, Arkansas with two replications, and F_2:6 seeds were harvested and analyzed for sucrose, stachyose, and inorganic phosphorous content. Results show a wide range of variation in the three traits studied with some lines having higher or lower values than the parents.  Effective combination of desirable traits was achieved in a number of lines; however, agronomic performance of these lines needs yet to be evaluated. Developing lines with high sucrose, low stachyose, and low phytate content could not only widen the current soyfood market, but it would also be environmentally beneficial by reducing the phosphorous contamination of ground water through livestock waste.