Relative responses of new malting barley cultivars to increasing nitrogen rates in western Canada

Abstract

O'Donovan, J. T., Anbessa, Y., Grant, C. A., Macleod, A. L., Edney, M. J., Izydorczyk, M. S., Turkington, T. K., Juskiw, P. E., Lafond, G. P., May, W. E., Harker, K. N., Johnson, E. N., Beres, B. L., McAllister, T. A., Smith, E. G. and Chapman, W. 2015. Relative responses of new malting barley cultivars to increasing nitrogen rates in western Canada. Can. J. Plant Sci. 95: 831–839. Only about 25% of barley (Hordeum vulgare L.) is selected for malting annually in western Canada due to quality issues. While nitrogen (N) fertilization can increase yield, it can also impair quality by increasing protein to unacceptable levels. The objective of this study was to determine the responses of relatively new malting barley cultivars (Bentley, Major, CDC Meredith, and Merit 57) to increasing N rates compared to the response of AC Metcalfe, the most commonly grown malting cultivar. Experiments were conducted at seven locations in western Canada in 2010, 2011 and 2012. Nitrogen was banded at seeding at 0, 30, 60, 90, or 120 kg ha−1. All the new varieties produced higher yield (5 to 11%) than AC Metcalfe. Barley kernel yield and protein concentration increased with N rate. However, Merit 57, CDC Meredith and Bentley produced significantly lower protein concentration in response to N than AC Metcalfe and Major. The newer cultivars displayed higher N utilization efficiency than AC Metcalfe, possibly due to partitioning proportionally more N into leaf chlorophyll development. The higher leaf chlorophyll content may have enabled increased photosynthesis and a more efficient utilization of N for grain formation. Bentley produced the least tillers and had the highest kernel plumpness, while Merit 57 had the lowest kernel plumpness. CDC Meredith lodged most followed by Merit 57, while Major and Bentley lodged least, especially at the higher N rates. Merit 57 and CDC Meredith took longer to mature than the other cultivars but yielded well at relatively short growing season locations.