Cob color, an indicator of grain dehydration and agronomic traits in maize hybrids

Abstract

Screening for agronomic traits associated with grain moisture is important for mechanical grain-harvesting of maize. Cob color as a visual indicator has received limited attention, though it has been subjected to artificial selection, and may have some association with threshability. To investigate the relationships between cob color and grain moisture and other agronomic traits, field experiments were conducted during 2016–2017 using 23 commercial hybrids with red or white cobs. Kernels of red-cob hybrids dehydrated faster, showing lower moisture content at harvest than white-cob hybrids. A cob color index (CCI) was established as a quantitative measure of cob color in the hybrid panel. Ranging from 0 (whitest) to 17.98 (reddest), CCI correlated well with grain dehydration and other agronomic traits associated with growth ontogeny, plant morphology, and plant N content. Strong selection of red cob for recently released hybrids suitable for mechanical grain-harvesting indirectly validated the observed link between cob color and grain dehydration. We propose that cob color and CCI could be used in future selection of maize cultivars bred for mechanical grain-harvesting.

Keywords

• Maize hybrids
• Cob color
• Grain dehydration
• Agronomic traits
• Artificial selection