Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: July 1, 2008
Publication Date: April 1, 2009
Citation: Cichy, K.A., Raboy, V. 2009. Evaluation and Development of Low Phytate Crops. In: Krishnan, H., editor. Modification of Seed Composition to Promote Health and Nutrition. Madison, WI: American Society of Agronomy and Crop Science Society of America. p. 177-201. Technical Abstract: Phytic acid (myo-inositol 1,2,3,4,5,6 hexakisphosphate) is the most abundant form of phosphorus (P) in plant seeds, representing ~70%±10% of seed total P. Non-ruminant, mono-gastric animals (poultry, swine, fish), typically do not efficiently digest and utilize seed-derived phytic acid P. This creates livestock production and management problems, both in terms of providing optimal P for animal productivity, and in managing waste P. In the context of human nutrition and health, dietary phytic acid can contribute to mineral deficiency, most notably iron and zinc deficiency, but may also have health beneficial roles as an anti-carcinogen and antioxidant. One approach to evaluating and possibly dealing with seed-derived dietary phytic acid's positive or negative roles is the development of low phytic acid (lpa) crop genotypes. In all lpa genotypes studied so far, the reduction in seed phytic acid P is mostly matched by increases in inorganic P, a form of P animals utilize well, so that seed total P is largely unaltered, and seed "available P" (in terms of animal nutrition) is increased. Poultry, swine and fish consuming lpa-based feeds utilize and absorb a greater fraction of feed total P, and excrete concomitantly less P. Both animal and human nutrition studies have shown that the use of lpa types in feeds or foods can enhance iron, zinc and calcium absorption and utilization. Thus the production and consumption of lpa crops could in theory mitigate mineral deficiency problems in the developing world. Here we review the current status of lpa crop genetics and breeding, and the agronomic and nutritional studies that have been conducted with lpa genotypes.