Changes in kernel characteristics during grain filling in silage-specific and dual-purpose corn hybrids

Abstract

<jats:p>Ma, B. L. and Dwyer, L. M. 2012. Changes in kernel characteristics during grain filling in silage-specific and dual-purpose corn hybrids. Can. J. Plant Sci. 92: 427–439. Silage-specific corn (Zea mays L.) hybrids have been gaining in popularity in recent years, but there is a lack of information about the difference in kernel characterization between Leafy silage-specific and dual-purpose hybrids. A field study was conducted for 4 yr to determine the changes in kernel moisture content, kernel dry weight, kernel nitrogen (N) and phosphorus (P) concentrations over the period of grain filling for Leafy silage-specific and dual-purpose hybrids at two plant population densities. In both types of hybrids, kernel dry weight content increased rapidly from approximately 2 wk after silking and reached a maximum at about 50 to 68 d after silking. While some differences among hybrids in kernel maximum dry weight were noted (P&lt;0.05), there was no distinction between hybrid types. The coefficients of kernel moisture change differed greatly between the two types with lower rates of decline of kernel moisture in some of the Leafy silage-specific hybrids (down-hill slope b&lt;0.0136±0.00044 g kg<jats:sup>−1</jats:sup>d<jats:sup>−1</jats:sup>) than the dual-purpose or silage hybrids without the Leafy characteristic (b≥0.0164±0.00039 g kg<jats:sup>−1</jats:sup>d<jats:sup>−1</jats:sup>). Higher plant population density had a negligible effect on kernel moisture decline and N and P concentrations, but reduced kernel dry weight by up to 7% in one year. Kernel P was linearly positively correlated with N content (r&gt;0.79, P&lt;0.01), and there was a linear relationship between kernel moisture and the whole-plant silage moisture content (R<jats:sup>2</jats:sup>≥0.70). Our data also showed that one of the Leafy silage-specific hybrids had higher rates of kernel dry weight accumulation and softer kernel hardness (P&lt;0.05) than the dual-purpose or non-Leafy silage hybrids. Our findings on the distinct characteristics of hybrid types are important considerations for corn producers to choose suitable hybrids and make decisions on silage harvest dates.</jats:p>

Evaluating maize and soybean grain dry-down in the field with predictive algorithms and genotype-by-environment analysis

“…During this phase, water is lost through physical evaporation from the grain surface 19 , a process primarily controlled by endosperm osmotic pressure and pericarp permeability 20,21 . Post-maturity grain dry-down typically follows a negative curvilinear response to days after physiological maturity 10,22 , and continues until grain moisture reaches equilibrium with the surrounding air 23 . This equilibrium moisture content depends on the properties of the drying material (e.g., grain type) and conditions of the air (i.e., temperature and relative humidity).…”

A regional analysis model of maize kernel moisture

“…For the grain-filling phase and the post-maturity drying phase, Piggott (2010) used the proportionality constants k developmental and k post-maturity , respectively, instead of the single constant k. The cutoff point for the two phases was physiological maturity based on the thermal time (base temperature of 8 ˚C) for effective grain filling. Another phasebased model, MIMYCS.Moisture (Maiorano et al, 2014), begins at the lag phase and then uses the equation M = M 0 e −at derived by Ma and Dwyer (2012) to predict the moisture in the grain-filling phase. Finally, when the simulated moisture concentration M decreases to M p (kernel moisture concentration at physiological maturity), the model enters the post-maturity drying phase and uses the equilibrium moisture concentration given by Thompson et al (1968).…”

“…These equations established relationships between moisture concentration and days from silking based on average reduction rates over several ranges. Later et al (2012) established an exponential decay equation for moisture concentration, M = M 0 e − at (where M is the moisture concentration, M 0 is the initial moisture concentration, and t is the number of days after silking), to express dynamic moisture concentration as a function of days after silking. These two approaches have since been used by researchers to develop moisture models (Maiorano et al., 2014; Van Ee & Kline, 1990).…”

“…A "black layer" develops at physiological maturity and prevents fluids from diffusing between the plant and the kernel (Daynard & Duncan, 1969;Rench & Shaw, 1971). Kernel moisture concentration (g g −1 or %, wet-weight basis, relative value) declines throughout the grain-filling period, even when the water content rapidly increases (Huang et al, 2012;Ma & Dwyer, 2001;Ma & Dwyer, 2012;Shinners & Binversie, 2007), before decreasing to about 20-45% at physiological maturity (depending on the genotype and weather conditions) (Borrás et al, 2009;Carter & Poneleit, 1973;Daynard & Duncan, 1969;Murray & Andrew, 2002). This decline is interpreted as a "developmental" loss of water associated with grain filling (Brooking, 1990).…”

Foliar Fungicide Application to Maize: Yield and Grain Hardness Enhancement in Different Environmental Conditions

“…This test was performed according to the method described by Blandino et al (2013) and Ma and Dwyer (2012). A 20-g kernel sample was ground by means of a Culatti micro-hammer mill (Labtech Essa) fitted with a 2-mm screen.…”