2009 Annual Report
1a.Objectives (from AD-416)
Develop maize germplasm for low-input and organic farming systems.
1b.Approach (from AD-416)
Organic farmers need germplasm that is not receptive to transgenic pollen from their neighbors as out-crossing risk is causing them to plant late, leading to reduced yields and profitability. Simple Sequence Repeat (SSR) markers will be applied in the context of an existing traditional breeding project using backcrossing to develop breeding materials homozygous for the genes Ga1-s (a gene that makes the lines non-recipient to foreign pollen), and Tcb1 and its positive modifier genes (another gene that makes the lines non-recipient to foreign pollen). We will determine the effect of combining different genetic mechanisms for producing corn with high levels of the essential amino acid methionine. Methionine is very important for organic poultry production in light of impending bans on the use of synthetic methionine for organic poultry farmers. A breeding project is conducted to provide farmers practicing organic and other low-input agricultural farming systems with high yielding corn, incorporating the traits described above among others, to meet their specialty markets.
We were able to plant most of our selection and breeding work on certified organic land in 2009 except for the projects involving breeding of specialty starch and oil traits and white corn. Priorities for selection and breeding under organic systems are high productivity and better grain quality, in particular high methionine content for food and organic feed. Most space in the winter nursery was devoted to breeding for altered fatty acid composition and making crosses and advancing lines that were lost due to the 2008 flooding. Wet conditions in the 2008 growing season caused late plantings and losses due to flooding prevented us from collecting reliable yield information on many of our organic farm sites, but by using winter testcrossing in Puerto Rico we obtained seed for 2009 yield testing. Enough grain was produced in 2008 from lines with increased levels of slowly digestible starch to use in an on-going study with humans to measure the effect on blood glucose levels, and lines were replanted in 2009 for additional human studies and feeding trials with laboratory rats to study colon effects. Two replications of a diallel crossing block to determine how different sources of high methionine complement each other in hybrids were flooded in 2008, and replanted in 2009 with three replications. Isolated fields were planted in mid-June for seed to distribute to farmers in 2010, 2010 yield testing, and for the pilot plant for research on our altered fatty acid lines. We will continue bringing in high methionine level genotypes into the organic breeding program to increase the methionine level of our high-yielding genotypes for use as organic poultry feed, in cooperation with the Michael Fields Agricultural Institute; testcrossing to measure yield potential, inoculation with diseases and infestation with European corn borer larvae to select progeny with disease and insect resistance; crossing and selection; and farmer outreach in cooperation with Practical Farmers of Iowa.
Corn lines selected for high seed quality in a conventional farming system should also have high seed quality when grown in a low input, organic farming system. Seed quality is critical for stand establishment of crops, especially in low-input farming systems where conditions may be more stressful at germination. ARS scientists in Ames, Iowa in collaboration with scientists at Iowa State University calculated parameters for seed quality for a set of high protein corn genotypes grown in conventional and organic fields and compared them to those of typical corn inbreds. The protein content was not affected by the farming system but oil content of the seeds produced organically was significantly higher than those produced in the conventional system. Corn seed destined for organic production may need better seed quality than that destined for conventional production, thus seed quality should be a selection criterion in organic breeding programs.
5.Significant Activities that Support Special Target Populations
For exposure to a wider group of small farmers, we started holding meetings of our farm-based seed association group for farmers who practice organic or low-input production and representatives of small seed companies. All meetings were well-attended by these farmers. Farmers are encouraged to take an active role in helping our project decide objectives, priorities, and germplasm to advance. We need small seed companies to help us with strategies for delivering seed from our project to farmers who want to produce grain using our germplasm. In winter 2009, we held a meeting at the Annual Organic Farming Conference in La Crosse, WI. This meeting, attended by farmers and representatives of many small companies catering to the organic and non-GMO producers, led to an initiative by the small companies along with public and independent breeders to jointly yield test precommercial (within one year) and elite breeding materials. Yield evaluations of these materials were planted spring 2009 in eight organic locations and 19 conventional locations in 10 states. We have several increases of synthetic varieties and variety hybrids distributed to farmers to try on-farm in quantities to plant about one acre or less in 2009.
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Simon, P.W., Pollak, L.M., Clevidence, B.A., Holden, J.M., Haytowitz, D.B. 2009. Plant Breeding for Human Nutritional Quality. Plant Breeding Reviews. 31:325-415.
De Geus, Y.N., Goggi, S., Pollak, L.M. 2008. Seed Quality of High Protein Corn Lines in Organic and Conventional Farming Systems. Agronomy for Sustainable Development. 28(4):541-550.
Taboada-Gaytan, O., Pollak, L.M., Johnson, L., Fox, S. 2009. Wet-milling Characteristics of Ten Lines from the Germplasm Enhancement of Maize Project Compared to Five Corn Belt Lines. Cereal Chemistry. 86:204-209