*2.3. Seed Yield and Yield Components*

In Experiment 1, seed yield of both LP-F10 and cv. Enrei was 1.7 times higher in the P150 treatment as compared with the P20 treatment (Figure 2). In Experiment 2 seed yield was 2.4 times higher in LP-F11 and 2.2 times higher in Akimaro in the P100 treatment as compared to the P50 treatment (Table 2). Importantly, in both experiments, in a given P treatment level the seed yield of the LP line was significantly (*p* ≤ 0.05) higher than the normal-phytate line, by 16% to 34%. Pod number data was not collected in Experiment 1. In Experiment 2, the number of pods per plant was significantly higher (*p* ≤ 0.05) in the P100 treatment as compared with the P20 treatment in both the LP-F11 line (2.1 times higher) and Akimaro (2.3 times higher, Table 2). Of importance here is that the pod number per plant of the LP-F11 line was higher than that of Akimaro in both P treatments; 1.41 and 1.28 times higher in the P20 and P100 treatments, respectively, but only significantly di fferent, *p* ≤ 0.05 in the P100 treatment. P treatment did not greatly a ffect 100 seed weight in either line or cultivar (Table 2). The 100 seed weight was about 1.6 times higher in LP-F11 than in Akimaro in both P treatments, but only significantly greater (*p* =≤ 0.05) in the P20 treatment.

**Table 2.** Effect of phosphorus fertilization on yield and yield attributes in LP-F11 and the normal-phytate cv. Akimaro in Experiment 2. The same letter indicates no significant di fference (*p* ≤ 0.05).


### *2.4. Seed Total P, Phytate P and Inorganic P Concentration*

In Experiment 1, the seed total P concentration in both LP-F10 and cv. Enrei was ~5–6 mg g<sup>−</sup><sup>1</sup> DW in the P50 treatment and ~6–7 mg/g DW in the P 150 treatment but did not di ffer between LP-F10 and Enrei (Figure 3A). The percentage of total P represented by phytate P in LP-F10 (~32–35%) was about half that of Enrei (~72–75%), and the percentage of total P represented by inorganic P in LP-F10 (~46–49%) was ~5–6 times greater than that of Enrei (~6–9%). Seed phytate P concentration within in a given line or cultivar was not consistently impacted by P treatment, whereas inorganic P was 15% higher in LP lines grown with P150 as compared with P50. Overall, similar results were observed in Experiment 2 (Figure 3).

### *2.5. Seed Crude Protein, Lipid and Mineral Concentrations*

Data for seed crude protein, lipid and mineral concentrations was only collected in Experiment 2 (Table 3). Seed crude protein and lipid concentrations in both LP-F11 and cv. Akimaro were about 10% higher in the P100 versus the P20 P treatments (Table 3). The seed crude protein concentration in both P treatments was 3% to 12% higher in LP-F11 than in the Akimaro; however, the lipid concentration was 5% to 12% higher in Akimaro that in LP-F11.

The K and Ca concentrations in the seeds of both LP-F11 and cv. Akimaro were 13% to 37% higher in the P100 treatment as compared with the P20 treatment (Table 3). While the seed Mg concentration in LP-F11 was not di fferent between the P20 and P100 treatments, the seed Mg concentration in Akimaro was 15% higher in the higher P application level. Seed K concentration in the P20 treatment was 17% higher in LP-F11 than in Akimaro, but no di fferences between lines were observed in the P100 treatment. Statistically significant di fferences in seed Ca and Mg concentrations were not observed between LP-F11 and Akimaro at a given level of P application. In contrast, the seed Zn, Mn, and Cu concentrations in both LP-F11 and Akimaro were 20% to 30% lower in the P100 fertilization level as compared with the P20 level, probably due to a dilution e ffect resulting from the higher seed yields at the higher P fertilization rate. With the exception of seed Fe levels in the P100 treatment and Cu at the P100 level, these element's concentrations were 11% to 43% higher in LP-F11 seed than in Akimaro in both P application levels. For both LP-F11 and Akimaro there was little di fference in the molar ratio of phytic acid to Zn, Fe or Mn between the two levels of P fertilization. However for Cu, the phytic acid:Cu molar ratio observed for the P100 treatment was 1.68 and 1.73 times as grea<sup>t</sup> in the P100 versus P20 fertilization levels for LP-F11 and Akimaro, respectively. Of importance for this study, due to Akimaro's 2.5 to 2.7-times higher level of phytic acid as compared with LP-F11, phytic acid molar ratios to Zn, Fe, Mn, and Cu were 2.5 to 3.5-times higher in Akimaro seed as compared with LP-F11 seed across both P fertilization treatments (Table 3).


**Table 3.** Effect of phosphorus fertilization on seed quality in the low-phytate LP-F11 as compared with the normal-phytate cv. Akimaro soybean in Experiment 2. The same letter indicates no significant di fference (*p* ≤ 0.05).
