Alberta Barley

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Effect of seeding rate and nitrogen rate on beta-glucan levels of hulless barley varieties across various soil and climatic zones in Western Canada

Project lead:
Dr. John O’Donovan
Research Scientist
Agriculture and Agri-Food Canada

Timeline: April 2013 – March 2018

Partners:
AB-AAFC-WGRF

Alberta Barley funding: $56,187
Total funding from other partners: $293,237

Benefits for barley farmers
As the food barley market in Canada expands, this information will be crucial to growers of barley for food.

Summary
The project will provide important information on the best seeding-rate and nitrogen-rate combinations to optimize beta-glucan levels in hulless barley varieties, and thus enhance the health value and market feasibility of the barley.

Recent developments – June 2016
The experiment was conducted as planned at all locations in 2015. A severe hail storm at Lacombe resulted in unusable data. Otherwise, all agronomic data were collected and analyzed. Results were generally similar to those obtained in 2013 and 2014. Plant emergence was slightly higher with the variety Rattan compared to Hilrose, and as a result, tillering was higher. Yield did not differ between the varieties but Rattan had higher protein. Preliminary interpretation of data for the quality variables (Canadian Grain Commission) from 2014 have been completed. Generally, trends were similar to 2013. Increasing nitrogen rates  increased the content of β-glucan but had no significant effect on soluble dietary fibre. Generally, increasing the seeding rate resulted in a decrease in the levels of β-glucans and soluble fibre, but an increase in the levels of arabinoxylans and insoluble dietary fibre. The results also indicated significant effects of genotypes, environments, and seeding rates on the composition, molecular structure and molecular weight of barley dietary fibre constituents.

Objectives for the upcoming year – June 2016
The experiment will be repeated for a fourth and final year in 2016.

Results
Barley grown for the food market desires higher β-glucan content. Most agronomic research so far have provided agronomic recommendations for malt and feed barley. It is therefore necessary to determine how agronomic practices such as seeding and nitrogen rates will affect barley grain beta-glycan contents. Beta-glucans are being recognized for their health benefit. If barley is grown to maximize beta-glucan content, producers will need to know what agronomic decisions to take to raise the beta-glucan content.

Two hull-less barley varieties (Rattan and hilose) were seeded at (200, 300 or 400 seeds m-2)and two nitrogen fertilization rates of 60 or 120 kg ha-1. Rattan tended to have the higher beta-glucan content out of the two tested varieties (not compared statistically).  Regardless of variety, beta-glucan content can be increased through increased nitrogen rate or decreased seeding rate. Lower seeding rates resulted in lower yields, so the recommended seeding rate will depend on the primary goal of production (beta-glucans vs. yield). High nitrogen rates increases lodging and days to maturity while lower seeding rates decreases yield and 1000 kernel weight. However lodging across site-years was relatively low.  Combining high nitrogen with a low seeding rate may best offset the negative impacts of each of the two agronomic decisions.

Updated July 16, 2018