Improving the bioavailability of seed phosphorous in low phytic acid soybean mutants

Abstract

Phytic acid, the heat stable anti-nutritional factor forms 75% of the total Phosphorous (P) in soybean seeds. It acts as strong chelating agent binding to metal ions reducing the bioavailability of Fe, Zn, Mg and Ca in human and non-ruminant livestock. In the present study, 106 soybean germplasm lines were screened to estimate the seed phytate. It ranged from 0.16 to 4.741mg per g soy flour. High yielding, low phytate cultivar were selected and subjected to 250 Gy gamma ray irradiation. In M3 generation, mutants having phytic acid content ranged from 0.075 to 2.58 mg/g of soy flour were identified. These mutants have shown as much as 50% or more reduction in seed phytate compared to control. Although low phytic acid line had much higher inorganic ‘P’ concentrations than seed of the normal lines, the balance between protein and oil content was not altered. Since, corn-soy and soymeal are commonly fed to livestock; reducing phytate content would contribute to increased bioavailability of ‘P’ in these livestock feeds.