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Spring wheat genotypes differentially alter soil microbial communities and wheat breadmaking quality in organic and conventional systems

A. G. Nelson1, S. Quideau2, B. Frick3, D. Niziol4, J. Clapperton5 and D. Spaner1

Abstract
Wheat (Triticum aestivum L.) cultivars may have differential effects on soil microbial communities and the breadmaking quality of harvested grain.

We conducted a field study comparing five Canadian spring wheat cultivars grown under organic and conventional management systems for yield, breadmaking quality and soil phospholipid fatty acid (PLFA) profile.

Organic yields (2.74 t ha−1) were roughly half of conventional yields (5.02 t ha−1), but protein levels were higher in the organic system than the conventional system (16.6 vs. 15.3%, respectively).

Soil microbial diversity measures were significantly higher in the organic system compared with the conventional system, including PLFA richness (31 vs. 27 unique PLFAs per sample, respectively) and PLFA diversity (Shannon diversity indexes of 2.90 and 2.73, respectively). Diversity measures were positively correlated with weed seed yield in the organic system (0.44<r<0.55), indicating that the presence of weeds played some role in increased microbial diversity. The use of composted dairy manure in the organic system may also have contributed to differences between the microbial communities in the organic and conventional systems.

In the conventional system, the most recent wheat cultivar, AC Superb, had higher levels of mycorrhizal fungi in the soil (1.97%) than the other cultivars (1.32−1.43).

Our results suggest that breeding efforts in conventionally managed environments may have resulted in cultivating mycorrhizal dependence in that environment. Cropping systems that include a diversity of plants, such as polycultures, may increase soil microbial diversity.


Source
Canadian Journal of Plant Science (2011) 91: 485-495
DOI: 10.4141/cjps10056


Author Locations and Affiliations
(1) Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5
(2) Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada T6G 2H1
(3) Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5A8
(4) Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada R3T 2M9
(5) Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada T1J 4B1


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Posted June 2011

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