Amanda Schoch, Department of Plant Science, North Dakota State University, Fargo, ND, Joel Ransom, Dept. of Plant Sciences, North Dakota State University, Fargo, ND and Jochum Wiersma, University of Minnesota, Crookston, MN
A minimum grain protein content of 14% is required to meet the market requirements of hard red spring wheat (Triticum aestivum L.) and avoid discounts. Previous studies have found that post-anthesis foliar applied nitrogen (N) applications can increase protein content by up to 1%. The current study was undertaken to determine if a simple diagnostic tool used prior to anthesis could reliably predict grain protein at harvest. Such a diagnostic tool will aid in the decision whether supplemental foliar applied N immediately following anthesis is warranted. Experiments were established at Crookston, MN, and Prosper, ND in 2011 and 2012 and consisted of a factorial combination on N rates (0, 68, 135, and 205 kg N ha-1 applied at planting) and cultivars of hard red spring wheat (Faller, Glenn, Samson, and Vantage). Instruments used to estimate the N status of the spring wheat crop were the Greenseeker Model 505 handheld optical sensor, CCM-200 chlorophyll meter, and a leaf color chart. A leaf and stalk tissue test were also taken to estimate the N concentration in these plant parts. Measurements were collected at Zadoks’ growth stages (GS) 16 and 37. Initial results in 2011at Crookston suggested a positive correlation between grain protein content and Greenseeker readings taken at the GS 16 and 37. Leaf tissue and basal stalk N concentrations were also positively correlated with final grain protein, with the leaf tissue samples collected at GS 37 having the highest correlation with grain protein of all variables (r =0.62). Results from 2012 will also be presented.