Evaluation of low phytic acid maize germplasm adapted to the Delmarva peninsula

The goal of this project is to develop high yielding low phytic acid maize specifically adapted to the Delmarva Peninsula. The majority of the phosphorus in grain is in the chemical form of phytic acid. Phytic acid cannot be digested by monogastric animals such as poultry and swine. Consequently, most of the phytic acid is excreted into the environment posing a serious environmental threat to waterways. Breeding and commercialization of low phytic acid maize hybrids using the low phytic acid 1 (lpa1-1) trait could potentially alleviate the serious environmental and nutritional effects of phytic acid. However, in-depth evaluations on potential negative effects of lpa1-1 on yield and other agronomic traits are critical to determining the commercial feasibility of the trait. The objectives of this project aimed to (1) Determine the effects of lpa1 on the 100 kernel seed dry weight and starch, protein, and oil content (2) Evaluate the effect of lpa1 on yield, agronomic traits, and plant growth and development of near-isogenic inbred lines and hybrids over multiple years and locations and (3) Screen exotic germplasm collections for new sources of low phytic acid loci or alleles. The results suggest that the 100 kernel seed dry weight and kernel composition were unaffected by lpa1 and are unlikely to influence the yield. However, negative pleiotropic effects on the yield and plant growth and development were observed for lpa1/lpa1. Overall, the yield decrease between lpa1/lpa1 and +/+ ranged from 0.4 to 7.9% by hybrid. The yield decrease was more exaggerated under stressful weather conditions and the extent of the decrease varied by background. One particular hybrid was identified in which the yield decrease was minimized and is recommended for future breeding. It is theorized that the negative effects on yield result from the cumulative negative pleiotropic effects on vigor and development. Plants homozygous for lpa1 may exist in a weakened state and suffer more cellular damage as a result of the disruption of phytic acid's antioxidant function. Screening of exotic germplasm has identified one potential new low phytic acid source with the potential for future research.