The Soil Microbial Community and Grain Micronutrient Concentration of Historical and Modern Hard Red Spring Wheat Cultivars Grown Organically and Conventionally in the Black Soil Zone of the Canadian Prairies

Abstract

Micronutrient deficiencies in the diet of many people are common and wheat is a staple food crop, providing a carbohydrate and micronutrient source to a large percentage of the world's population. We conducted a field study to compare five Canadian red spring wheat cultivars (released over the last century) grown under organic and conventional management systems for yield, grain micronutrient concentration, and soil phospholipid fatty acid (PLFA) profile. The organic system had higher grain Zn, Fe, Mg and K levels, but lower Se and Cu levels. There was no trend in the results to suggest that modern western Canadian hard red spring cultivars have lower grain micronutrient content than historical cultivars. Wheat cultivar choice is important for maximizing grain nutrient levels, OPEN ACCESSSustainability 2011, 3 501 which was influenced by management system. It is evident that the emphasis on elevated grain quality in the western Canadian hard red spring class has resulted in the retention of micronutrient quality characters. Three fungal PLFAs were indicators for the organic system, and all three of these indicators were positively correlated with grain Cu concentration. In the organic system, percent arbuscular mycorrhizal fungi were negatively correlated with grain Zn and Fe concentrations, and positively correlated with grain Mn, Cu, K concentrations and grain yield. The organic system had higher levels of fungi in the soil, including arbuscular mycorrhizal fungi. Organic management practices appear to result in elevated levels of grain micronutrient concentration. The hard red spring breeding effort in and for the black soil zone of the northern Great Plains also appears to have led to no diminishment of grain micronutrient concentration. It is evident that both the agronomic system and breeding strategies in this region can be exploited for future increases in grain micronutrient concentration.

Microbiota in Wheat Roots, Rhizosphere and Soil in Crops Grown in Organic and Other Production Systems

“…It was bred in 1999 (not specifically for organic production), and usually has greater yield, more resistance to stem-base and leaf diseases, better grain quality and more weed suppression than other wheat cultivars (Anonymous 1999;Ku s et al 2010). Other cultivars may have had different effects on soil microbial communities (Nelson et al 2011). There was often inconsistency between microbial community structure and disease severity and grain yield. Pathogen:antagonist ratios were not always correlated with disease severity.…”

Plant breeding for organic agriculture: something new?

“…Genetic variation and genomic regions associated with the uptake of micronutrients have also been reported in wheat [40,41]. Nelson et al [42] found, however, that the percent of arbuscular mycorrhizal fungi was negatively correlated with iron and zinc concentrations in winter wheat, but positively correlated with manganese, copper, and potassium. Mycorrhizal fungi play an important role in soil fertility and nutrient uptake in OF systems, whereas in CF their presence is severely reduced [43].…”

Selenium accumulation by plants

“…Genetic variation in grain Se concentration has been reported for a number of cereals (Table 1). Although several studies have suggested little genetic variation in grain Se concentration among bread wheat (Triticum aestivum L.) genotypes (Table 2; Lyons et al, 2005a;Zhao et al, 2009;Lee et al, 2011;Nelson et al, 2011), other studies have reported significant genetic variation in this trait (Garvin et al, 2006;Murphy et al, 2008;Rodrı ´guez et al, 2011;Pu et al, 2014). It is evident that the expression of this trait in bread wheat is strongly dependent upon weather conditions, crop husbandry and Se fertilization (Lyons et al, 2005a;Garvin et al, 2006;Zhao et al, 2009;Lee et al, 2011;Nelson et al, 2011).…”