Organic producers have repeatedly said that varieties selected under conventional management may not be suited to organic production.
In a presentation at Organic Connections 2006, graduate student Todd Reid’s research poster explored this question, asking if organic spring wheat breeding is necessary.
In his research, Reid crossed different varieties of wheat and grew their descendants under both organic and conventional management. He has 79 wheat lines, grown in eight site years.
In an initial analysis of his results, he compared the lines that were in the top 10 percent for yield under organic management with the top 10 percent under conventional management. These two groups had only one member in common.
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While Reid’s analysis is still preliminary, the results indicate that selecting the best lines under conventional management, as is commonly done, may not produce the best lines for organic production. This suggests that organic producers could benefit from breeding programs oriented to their style of farming.
Reid’s project was one of the three top graduate student posters recognized at the conference. Alison Nelson and Heather Mason were also credited for quality research.
The students’ posters were selected from contributions originating from Alberta to Ontario.
The panel of judges included research, business development and extension experts in organics on the Prairies. The contest was organized by the Organic Agriculture Centre of Canada, with prize money provided by the Saskatchewan Organic Directorate.
Nelson and Mason explored ways of improving wheat productivity. Nelson’s poster asked if annual intercrops help control weeds and improve productivity.
She grew wheat, barley, canola and field peas by themselves, and in combinations that included wheat, such as wheat with barley, wheat with canola and wheat with barley and canola.
When two crops were grown together, they were each seeded at half the rate than if they were grown alone. If three crops were grown together, each was seeded at one-third the solo rate. The test was grown at two conventional sites and two organic sites.
Nelson found that barley and wheat mixtures had lower weed biomass than mixtures with field peas or canola.
Then she compared the land equivalence ratio of various mixtures.
This measure indicates if yields are higher when the crops are grown together or when grown separately.
Several intercrops, including wheat with barley and canola and wheat with barley and peas, yielded higher when grown as intercrops.
Although the results are preliminary, this suggests that intercropping less competitive crops like canola and pea with more competitive ones such as barley may suppress weeds and improve productivity.
Mason looked at increased seeding rate as a way to improve competitive ability of different varieties of spring cereals. She hoped to identify the traits that make cereals more competitive.
The varieties she chose were of different heights, different rates of maturity and produced different numbers of tillers.
Mason found that height, early maturity and early vigour were important to weed suppression and to maintaining yield in weedy conditions. Tillering ability was less important.
CDC Go, a new, short spring wheat variety, was high yielding, but did not compete well with weeds. Katepwa and Park, which are older, taller spring wheat varieties, showed the best combination of grain yield with weed suppression. For all varieties, doubling the seeding rate increased grain yield, improved weed suppression and improved economic returns.
Frick is the prairie co-ordinator for the Organic Agriculture Centre of Canada located at the University of Saskatchewan. She can be reached at 306-966-4975, at brenda.frick@usask.ca, or www.organicagcentre.ca.
