Development of New and Alternative Resources for Breeding Low Phytate Soybeans

Soybean (Glycine max (L.) Merr) cultivars with genetic reduction in seed phytate concentration will be a valuable resource to livestock producers both nutritionally and economically, as well as in the preservation of the environment. However, due to association with reduced seed germination and field emergence potential, low phytate (LP) soybean cultivars are not being advanced to commercialization. Soybean breeders of LP lines must adjust their techniques and resources in order to efficiently select LP germplasm. Reduced seed germination and field emergence potential associated with LP germplasm eliminates many individuals with the desired LP trait during early generation population development, making improvement of agronomic performance among LP lines difficult. Thus, development of resources for improved phenotyping, genotyping, and early generation population development will facilitate the commercialization of LP cultivars. Discovery of variation for field emergence potential among F2-derived LP families suggests the potential for using a pedigree method for early generation population development in LP germplasm, as it preserves diversity and allows selection for improved field emergence. Integration of markers into a pedigree method will be useful to breeder. An example is BARCSOYSSR_11_1495 with 90-93% selection efficiency in various V99-5089-derived populations. Another resource for improved LP selection is a time-efficient, high-throughput modified iron (Fe) colorimetric phytate assay that does not suffer from inorganic phosphorus (P) concentration interference. Together these tools will provide breeders more accurate selection of