Area Under the Dry Down Curve (AUDDC): A Method to Evaluate Rate of Dry Down in Maize

Abstract

Maize ( Zea mays L.) hybrids with fast field dry down are economically desirable across production regions. However, accurately measuring this genetically complex trait in a simple way has been a challenge to maize breeders. The objective of this research was to propose and test an efficient, simple, and reliable procedure to select genotypes with fast dry down in maize. Area under the dry down curve (AUDDC), an index representing the dynamic progress of field dry down, was proposed. The main experiment included 144 hybrids arranged in a partially balanced lattice design across four short‐season environments in North Dakota. Data collected were silking date, ear moisture at four 7‐d intervals starting 45 d after pollination, harvest moisture, test weight, and grain yield. Results showed significant genotype × environment interaction for most traits including AUDDC. However, AUDDC had the largest broad‐sense heritability (H) among traits (0.84), suggesting it can be effectively utilized to identify faster drier inbred lines and hybrids. Strong correlations were found between AUDDC and silking date, AUD and moisture content at physiological maturity, and AUDDC and harvest moisture. Area under the dry down curve is proposed as an indirect measurement for dry down rate and we encourage its use to develop lines and hybrids with faster dry down.