Seed Inorganic Phosphorus Stability and Agronomic Performance of Two Low Phytate Soybean Lines Evaluated Across Six Southern U.S. Environments
Boehm, J.D., F. R. Walker, H. Bhandari, D. A. Kopsell, and V. R. Pantalone.  2017.  Crop Science, 57:1-9.

Non-digestible phytate salts that chelate nutritional minerals in the digestive tract of livestock are an unwanted component of soymeal and a documented source of non-point phosphorus (P) pollution in the waste stream detrimental to the environment. Lowering soybean phytate levels would ease environmental concerns and improve soymeal mineral bioavailability. In 2013, a field trial consisting of two University of Tennessee low phytate (LP) lines (56CX-1273 and 56CX-1283) and two high yielding check cultivars (5002T and Osage) were planted in four row plots in two replications at six Southeastern locations in a randomized complete block design to evaluate the LP lines for agronomic performance, seed quality traits and inorganic phosphorus (Pi) stability. Results revealed that there were no significant differences (P > 0.05) for mean seed yield between the two LP lines (3854 kg ha-1) and the two cultivars (4286 kg ha-1). Although the genotype by environmental (G E) index linear regression of seed Pi for the two LP lines revealed a slope that was significantly different (P < 0.001) from zero, and therefore not stable across the six environments, the mean Pi concentrations for LP lines 56CX-1273 (2084.7 g g-1) and 56CX-1283 (1744.4 g g-1) were still about an order of magnitude greater than the means of Osage (185.7 g g-1) and 5002T (228.0 g g-1). This study documents that a LP line can produce seed yields statistically equivalent to high yielding check cultivars.