Can anoxic atmospheres protect the quality of maize seeds during storage?

Abstract

Low oxygen atmospheres have proven to be effective to protect seed quality in many species during storage. In maize, however, the evidence is ambiguous since positive, negative, and neutral effects were reported. These apparent contradictions might relate to the different experimental conditions explored in previous studies (i.e., combinations of oxygen concentration, relative humidity, and temperature). The aim of this work was to study the effect of anoxic atmospheres (<1% oxygen) on germination and vigor of maize seeds stored under five combinations of relative humidity and temperature (65%, 75%, and 85% relative humidity at 25 °C, and 65% relative humidity at 30 °C and 35 °C) under strict control of experimental conditions. Data of germination and radicle emergence (vigor) were analyzed using Generalized Linear Models. Our results show that the effect of anoxia on seed quality depends on relative humidity and temperature. At 25 °C, anoxia benefited both germination and vigor at 75% and 85% relative humidity compared to the normal atmosphere, while at 65% relative humidity the benefit was only detectable on vigor. Additionally, the benefit of anoxia on germination was higher at a relative humidity of 85% than at 75%. At 30 °C and 35 °C and 65% relative humidity, anoxia was neutral to seed germination and vigor. Anoxia, in conclusion, benefits seed quality under particular combinations of relative humidity and temperature usually found in real storage conditions. This turns anoxic storage in a potential technology to extend the shelf life of maize seeds for both small-farmers and seed companies.