NUTRIENT DENSITIES, CARBON: NITROGEN RATIOS, AND MIDDAY DIFFERENTIAL CANOPY TEMPERATURE IMPACT GRAIN YIELD OF STRESSED OAT

Abstract

Nutrient densities, carbon:nitrogen (C:N) ratio, and midday differential canopy temperature (dT), were assessed in oat plants subjected to biotic stresses during two years. Large portions of variation in nutrient densities and C:N ratio of leaves at the boot stage and of kernels and groats at harvest were negatively impacted by the 2- and 3-way interactions of leaves, kernels, and groats with the biotic stress treatments and years. The C:N ratios, but not nutrient densities, were always smaller in groats than in kernels, and during the stress than the no-stress year. Temporal variation accounted for a small variance associated with nutrients in leaves; whereas, stress treatments accounted for the largest variances associated with nutrients in kernels and groats. These indirect relationships among plant architecture components, dT, nutrient densities and C:N ratios, illustrate the complex interactions of biotic and abiotic stresses and their impact on grain yield and its components in oat.

Keywords:

• C:N ratio
• nutrient dynamics
• biotic stress
• yield models
• oat

ACKNOWLEDGMENTS

We thank Dave Schnider, Jana Rinke and Jay Hanson for technical assistance and Beth Burmeister for editing the manuscript. The use of trade, firm, or corporation names in this publication is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the United States Department of Agriculture or the Agricultural Research Service of any product or service to the exclusion of others that may be suitable. USDA is an equal provider and employer.

This article not subject to US copyright law.

Notes

^†

∗, Significant differences (P < 0.05) between means of the 10 combinations of year-stress treatments.

^†, [L], [K], and [G]: total nutrients density in leaf, kernel and groat, respectively.

^†

∗, validation Q² value is significant at P < 0.05 (Tukey's, HSD).

^†

∗, significant at P < 0.05 (Tukey's, HSD).