Plant Genetic Approaches to Phosphorus Management in Agricultural Production

Abstract

AbstractMuch of the P in corn (Zea mays L.) grain is present in the form of phytic acid. Phytic acid P is unavailable to monogastric animals with most being excreted in the waste. As a result, the substantial P stores in grain are essentially wasted and may contribute to water pollution rather than animal productivity. The initial goal of this research was to isolate chemically induced mutants with reduced levels of phytic acid P in corn. Such mutants, referred to as low phytic acid or Ipa, were isolated and were found to have little or no other effect on kernel composition including no effect on total grain P content. The first mutant characterized, Ipal‐1, a 65% reduction in phytic acid and is accompanied by a molar‐equivalent increase in inorganic P. This mutant was backcrossed into elite corn inbred lines and resulting hybrids were evaluated for yield and other important agronomic traits. Preliminary field trials indicated germination, stalk strength, grain moisture at harvest, and flowering date were not affected by Ipal‐1. Some, but not all, Ipal‐1 hybrids had yield reductions. In a preliminary chick feeding trial, the low phytic acid grain resulted in greater P availability and reduced P content in the waste. Altering the phytic acid content genetically in corn is possible and may have the potential to improve feeding efficiencies and reduce P released to the environment.