| Predicted grain yields enable producers to more accurately apply the needed top-dress nitrogen (N) which leads to improved N use efficiencies and increased profit. This study was implemented to correlate and determine the relationships between winter wheat (Triticum aestivum L.) plant characteristics and grain yield to better predict grain yields mid-season. A two year, randomized complete block design field experiment, with three seeding rates (63, 120, and 176 kg ha-1) and three N rates (0, 56, and 112 kg ha-1), was established at two locations (Hennessey and Lahoma, Oklahoma) in the fall of 2009. Regression, correlations, and analysis of variance were used to determine the degree to which each variable was able to predict final grain yield.;Fall tillering is important, but wheat can overcome poor fall tillering and produce an adequate yield. Early season biomass accumulation partially due to higher seeding rates, resulted in increased grain yields, and N use efficiency. Feekes 5 and 7 NDVI proved to be the best mid-season predictors of grain yield with r2 = 0.62 and 0.68, respectively. Nitrogen uptake, biomass, and forage N were also well correlated with grain yield (r 2 = 0.61, 0.44, and 0.40 respectively) and should be used with F5 and 7 NDVI to aid in determining the ideal mid-season top-dress N rate. |
