Location: Corn Insects and Crop Genetics Research2013 Annual Report
1a. Objectives (from AD-416):
The objectives of this research are to 1) breed high yielding corn with enhanced nutritional value for the Northern Corn Belt, 2) adapt the corn to the conditions found on farms using sustainable farming practices, and 3) achieve acceptance of these cultivars by end users such as livestock farmers and poultry producers.
1b. Approach (from AD-416):
1)Interact with a team including USDA and ISU scientists and PFI to select varieties for breeding, plan experiments, test corn, develop methods for screening lines for desired traits, and for outreach and publication efforts. 2)Utilize a crossing, inbreeding and test-cross facilitated breeding program to identify and fix corn lines with desired traits, and crossing and recurrent selection to improve desired traits such as the content of methionine and lysine in grain. 3)In conjunction with others, fully utilize and improve the accuracy of a near infra red spectroscopy-based test for screening whole grain samples for essential amino acids. 4)Evaluate the adaptation of lines and their hybrids to organic farming systems in the Northern Corn Belt, including their agronomic traits and their ability to suppress weeds. 5)Help coordinate on-farm trials with hybrids and publicize the results. 6)Interact with end-users such as seed and organic poultry companies with advice and to help facilitate poultry company sponsored feeding trials with grain from our cultivars.
3. Progress Report:
Michael Fields Agricultural Institute’s (MFAI) project involved breeding corn for superior nutritional value including increased content of essential amino acids. These varieties are adapted to low input, sustainable farming conditions where nitrogen is derived from the decomposition of soil organic matter and manures, and where the corn will need to out compete inherent weed populations because herbicides are not used. All selections are made under organic cropping conditions. Their objectives focused on developing inbreds/populations that when made into hybrids have: 1) high methionine content in grain to satisfy the needs of poultry; 2) high standing ability, grain yield, and quick dry-down of grain; 3) disease and insect resistance; 4) superior ability to compete with weeds. Over the 5 years, breeding and yield trials have focused on developing new types of cultivars including: • Single cross hybrids made by crossing inbreds that have quality and yield. • Topcrosses made by crossing inbreds and populations to combine yield and quality. • Varietal hybrids made by crossing open pollinated populations with each other. • Open pollinated populations or synthetics with quality and yield. MFAI carried out multiple years of replicated field trials in Wisconsin and in Iowa and the results suggest the following: • Topcrosses appear to be the most immediately applicable to commercialization of their breeding lines. • Some topcrosses may produce yields competitive with conventional hybrids. • The seed of topcrosses may be cheaper to produce than the seed of single cross hybrids because populations compete better with weeds than inbreds. • Topcrosses have slightly more lodging and grain moisture. • Topcrosses may convey more quality to the hybrid. Varietal hybrids: crosses between populations or varieties • They have generally lower yields but several may be competitive with conventional hybrids. • The seed of varietal hybrids may be cheaper than the seed of single cross hybrids and the variety component competes better with weeds than do inbreds during the seed production phase. • Several may be especially competitive in the North. • They have the potential of providing greater quality corn to farmers quickly. • They can be adapted to organic conditions. MFAI’s strategy involved crossing complementary lines and selecting their offspring through three cycles of inbreeding coupled with evaluating test crosses with these lines. The best lines are to be used per se or recombined to produce narrow populations with good vigor to use as seed stocks. Breeding for grain quality: protein and methionine levels were evaluated using near infra-red spectroscopy. Increased protein and methionine levels improve feeding quality for humans and livestock. Methionine is a limiting essential amino acid in poultry rations and is typically supplemented in synthetic form. Increased methionine levels in feed corn would reduce the amount of synthetic methionine used; this is especially important in the organic sector. MFAI assembled corn with these genetic systems and have been breeding with them. They include: • Enhanced contents of high methionine delta zein storage proteins (hard endosperm, dzr1 gene). • Decreased contents of alpha zein and increased proteins with more methionine and tryptophan (floury-2 gene). • High oil corn (hard endosperm, large embryo size). In 2008, high methionine breeding lines representing germplasm from diverse backgrounds: plant introductions, and non-Genetically Modified Organism (GMO) conventional germplasm, were planted for feeding trial testing and evaluation. The University of Minnesota completed a feeding trial with layers using floury-2 corn from MFAI. Seventy five day-old pullets were fed either a control diet containing conventional organic corn and synthetic methionine or a diet containing high methionine corn without supplemental methionine. Birds fed the high methionine corn appeared to consume in luxury quantities if they could. After 45 weeks, results suggest there were no large differences in food consumption, egg production or egg weight between the two diets. The hens fed the control diet produced more very large eggs. By the end of the trial half of the control diet group were eating their own eggs. Both broiler and layer trials suggest either that the soft kernelled high methionine corn is preferred by the poultry or that they are responding to nutritional differences in the grain. Analysis of MFAI corn in 2007 showed that many populations have enhanced contents of carotenoids which are antioxidants that have a role in human and animal health. MFAI continue to practice selection for seed that has intensely orange and yellow coloration associated with the presence of elevated carotenoids. Yield trials in 2009, tested different kinds of high methionine corn and included a white and yellow corn trial. The yield drag associated with growing high methionine corn is 90% to 70% of conventional hybrids. Throughout the five year period, high quality lines been multiplied and new hybrids have been made for testing. All lines have been evaluated for agronomic characteristics. All inbreds have been evaluated for their ability to compete with weeds. Our 2012 breeding research focused on the concurrent development and testing of open pollinated, inbred, and hybrid corn varieties with stability of grain yield and high quality adapted to organic crop production conditions. Open Pollinated (OP) varieties permit growers to save part of their harvest to use as seed for planting in future seasons. The industry standard for corn is hybrid varieties due to the perception of superior quality, uniformity and performance as promoted by the proprietary seed corn industry. Both OP and hybrid seed corn varieties have a place in organic crop production programs. In 2012, soil sampling and analysis was conducted on all areas planted prior to plant breeding research. Low nitrogen fields were identified for nitrogen use evaluation study. A comparison of nitrogen use efficiency and atmospheric nitrogen fixation will be conducted in a replicated evaluation trial. Tissue samples were collected and will be analyzed using the 15N natural abundance technique. Evaluation of yield via replicated variety trials included a bacterial inoculation trial and a replicated trial of our diverse breeding lines: hybrid and OP. In 2013, high quality inbred lines with superior agronomic traits representing germplasm from diverse backgrounds were planted in replicated randomized inbred evaluation trial. Already weed competitive, the inbreds are being evaluated for their agronomic traits, lodging and disease resistance, and protein and methionine content of grain. Test crosses were made to determine combinability. Breeding for other characteristics: In 2008, the need for breeding corn that will not accept pollen from transgenic corn became apparent. This corn is called ‘gametophytic incompatible’. Gametophytic incompatibility is a genetically inherited system in which the silk will not allow proper growth of pollen tubes if the mother plant possesses the Ga1s gene or the Tcb-1 gene. These genes occur in nature and effectively isolates popcorn from pollination by field corn. Gametophytic incompatibility gene can limit contamination from external pollen sources, i.e. GMO pollen. A 2011 yield trial for evaluation of nitrogen utilization and efficacy of bacterial inoculation was planted to evaluate atmospheric nitrogen utilization. Nitrogen use efficiency and atmospheric nitrogen utilization was determined in a replicated yield trial utilizing low and normal nitrogen fertility levels, with and without bacterial inoculation. The nitrogen source utilized was independent of other nutrient sources permitting reservation of a low nitrogen fertility area for direct comparison of performance to plots with recommended levels of nitrogen. Tissue samples were collected and nitrogen use determined using the 15N natural abundance technique. Commercialization: The commercial development of high methionine corn depends on more than breeding breakthroughs. At presentations to the Methionine Task Force and the National Organic Program, MFAI emphasized the need for planning and coordination, and clear relationships between farmers-grain handlers, and poultry producers. If high methionine corn is to develop to fill the need for organic methionine, several things have to take place: • Continued progress with high methionine corn hybrids. • A sufficient level of consensus by companies that corn is an option to support and a coordinated plan of action. • Testing, breeding, and multiplying of seed-stocks, and production of hybrid seed. • Adequate price incentives and contracts that stipulate that incentive. • Information sharing with farmers and companies. • Cultivation of resources and relationships between interested participants in an expanding team. Summary: MFAI’s emphasis on coupling yield, high quality grain and agronomic traits needed for organic crop production is unprecedented. Their program continues to emphasize the development of vigorous heterozygous breeding stocks that out compete weeds during seed production, and to provide stocks that can continue to evolve with farm conditions. They are making progress in developing new, unique corn varieties, not duplicated in the private sector but needed by the organic sector. Their future direction is to release cultivars fitting an organic ideotype which includes grain quality, agronomic reliability and excellent grain yield.