An Evolutionary-participatory Approach for Breeding Self-pollinating Cereals in Organic Systems

Direct selection within organic systems has been shown to increase grain yield in organic wheat from 5% to 30% when compared to indirect selection within conventional systems.  However, the cost of maintaining a separate, viable breeding program for organic cereals can be logistically and economically challenging.  The multiplicity of inputs and practices of organic cereal farms in a target bioregion tends to lead to greater landscape diversity than is often found among conventional farms in the same region.  Genetic uniformity within most homogeneous cereal-based monocultures has been shown to limit the crops’ capacity to evolve in response to adverse and challenging environmental conditions. Therefore a practical, low-cost approach to organic cereal breeding may be beneficial to fully exploit the range of genotype x organic farming system x environment interactions within the target region.  One such approach is through a fusion of participatory and evolutionary breeding models.  This model relies on robust on-farm, farmer-breeder co-selection of preferred genotypes within segregating, heterogeneous bulk populations. In an evolutionary breeding study, several F₈-F₉winter wheat populations were shown to out-yield parental cultivars within and across selection environments, while maintaining protein contents similar to the mid-parent value. The use of single nucleotide polymorphism (SNP) sequencing and visualization has identified specific markers (and alleles) within known quantitative trait loci (QTL) that are favored through natural selection are potentially associated with increased traits related reproductive fitness, including grain yield, plant height and heading date. One farmer-bred, evolutionary-participatory population of winter wheat, WA8094, was included in the WSU Statewide Variety Testing program in 2009–10 and 2011–12 with 59 of the most promising breeding lines and established varieties from 11 regional breeding programs.  In 2009–10, WA 8094 yielded the same as the most widely grown variety statewide in dry areas, ‘Eltan’, and significantly higher than ‘ORCF-102’, ‘WB0528’, and ‘Madsen’ (ranked 2,4, and 5, respectively, in Washington acreage) when averaged across six low rainfall locations.  In 2010–11, WA8094 was statistically equal in grain yield to Eltan, WB-523 and AP 700 CL (which had replaced Madsen), though lower to Xerpha and ORCF-102.  The fact that a bulk population, bred using recurrent selection, both natural and farmer-imposed, could rank high across elite variety trials demonstrates the potential for this low-cost method to be used in farmer-breeder collaborations across a broad range of organic systems.