Genetic Improvement of Seedling Emergence of Low-Phytate Soybean Lines

Phytate (myo-inositol 1,2,3,4,5,6-hexakisphosphate) is the pri-mary source of P in soybean [Glycine max (L.) Merr.] (Erd-man, 1979). Phytate P (PAP) is poorly utilized in swine, poultry, and other nonruminant animals because they lack suffi cient phy-tase enzyme to break down the phytate molecule (Cromwell et al., 2000). Phytate also binds to micronutrients and renders them unavailable to the animal (Adeola et al., 1995). The P in the excre-ment of these animals, when applied to the soil in excess amounts, can be detrimental to the environment because of its associated increase in eutrophication (Daverede et al., 2004). Four genes have been reported in soybean that cause a reduc-tion in PAP and an increase in inorganic P (Pi) in soybean seed. The recessive mips allele is responsible for reducing phytate P and raffi nose saccharide content (Sebastian et al., 2000). Gm-lpa-TW-1 and Gm-lpa-ZC-2 are recessive mutant alleles that can independently produce the low-phytate (LP) phenotype (Yuan et al., 2007). The combination of the recessive pha1 and pha2 alleles also produce the LP phenotype (Oltmans et al., 2004). All of th