Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: Strengthening Public Corn Breeding to Ensure That Organic Farmers Have Access to Elite Cultivars: Stress Nurseries

Location: Corn Insects and Crop Genetics Research

2012 Annual Report


1a.Objectives (from AD-416):
1) Cooperate in the breeding effort through stress evaluations,.
2)participate in outreach activities, and.
3)cooperate in planning, execution, and reporting of experiments and breeding plans.


1b.Approach (from AD-416):
Stress evaluations will include the following evaluations. Cold germ selection: each year as many as 50 S0 bulk (2500 seeds per entry) breeding crosses will be screened for their ability to germinate after prolonged exposure to 40 degrees F in saturated rag rolls for approximately 3 weeks. Individual survivors (target 250 per breeding cross) will be identified and then shipped to breeder's nurseries for transplanting, further selection, inbreeding and testing. Plots will be scored visually on a 0-9 scale for damage to late season plant integrity in an organic nursery near Clinton, Illinois. Central Illinois is an excellent environment for selecting against leaf disease and root lodging due to combinations of wind, rain, Western corn rootworm and Anthracnose. This will provide information on the ability of the breeding lines to tolerate multiple stressors. Furthermore, each year self-pollinations will be made within the top 5 percent of the rows in the stress nursery (150 most promising rows of the best early segregating S1, S2, S3 generations or narrow synthetics) in order to identify individual plants most tolerant to multiple stressors. These plants will be returned to the breeders for more work. Treatments include: accelerated aging, notes on stand establishment, vigor, uniformity and any other stand related abnormalities, and root & stalk lodging. Plots will be visually assessed for percentage of plants that are root or stalk lodged and for the severity of the leaf diseases. Artificial inoculation will occur for gray leaf spot, Anthracnose leaf blight, northern leaf blight, northern leaf spot, southern leaf blight, and common rust. Stewarts Wilt occurs naturally each year as there are enough flea beetles to spread it. Starting the last week in August, plots will be visually rated for percentage of leaf area still green (SG) every week. Sums of the percent green tissue for 2, 3 or 4 ratings will be used to characterize entries by computing areas under disease progress curves. Artificial inoculation with stalk rot: within 3 days of plots reaching 50% silk, the last 10 plants in each plot will be inoculated with organisms in the soil by dipping a nail mounted on a stick into the soil and then forcibly injected into the center of the first elongated internode above the ground. Plots will be scored for premature death and late season plant integrity on a 0-9 scale.


3.Progress Report:

The overall emphasis of Montgomery Consulting work is to provide germplasm for evaluation, screen germplasm sources for various pest reactions and stresses including reaction to cold shock, characterize the ability of germplasm sources to withstand prolonged exposure to saturated conditions at 38 degrees Fahrenheit and still germinate and achieve viable plants, produce new hybrids that have competitive ability and nutritional quality (methionine and lysine), high carotenoid content, and are adapted for high productivity under organic or low input farming systems, including under low nitrogen conditions. Additionally, advice is provided to other team members on stress testing, quantitative genetics and conventional corn breeding issues like heterotic patterns and tester choices. Finally, nurseries are worked to meet specific collaborator needs including inter-institutional crosses and observations that fall outside the specific scope of the stated details of the project. The cooperator spent extensive consulting time regarding the transfer of the breeding program from Michael Fields Agricultural Institute (MFAI). These discussions centered around maintaining progress and continuity. The effort so far has created breeding lines. Most are high yielding as inbreds per se, some have elevated protein, methionine, lysine, and carotenoids, some have potential for efficient nitrogen use, while most are designated for use as females and have above average leaf disease and stalk rot resistance. Of primary concern is information on the combining ability of new lines for making competitive commercial hybrids. This information will enable us to determine which lines and populations deserve more breeding work. Therefore, it seems important to focus our efforts on making test hybrids, evaluating them, and then proceeding further with those that have been proven to have both quality and yield. In practice this means more summer isolations for making test hybrids with already existing breeding lines, more focused summer nursery work, and greater reliance on winter nurseries for advancing and increasing the best lines. Eight segregating breeding populations, synthetics, were sent to Ames, IA, Lake Geneva, WI, Ithaca, NY, and Las Cruces, NM for cooperative population trials. These populations represent some of the better breeding populations used at Montgomery Consulting for developing inbreds and improved germplasm sources while some are a replication of entries tested the previous year. In addition, a set of populations was received from Cornell, Mandaamin Institute, New Mexico State University (NMSU) and USDA for cooperative testing. Those populations are being compared with populations from Montgomery Consulting on each site, including a randomized complete block experiment in Maroa, IL managed by Montgomery Consulting. Additionally, five more synthetics were used to replace local checks when it became apparent that those local checks would not be forwarded for the tests in Illinois. Because of the late arrival of seed, the tests were planted extremely late. The area is too large and too remote to provide supplemental water in a meaningful way. It will be a challenge to get data from these disease and insect pest trials. Twenty three germplasm sources were screened for cold shock characteristics. Of these Cornell sent five; Mandaamin Institute sent seven, USDA sent five and Montgomery Consulting contributed six. At least 250 responsive seedlings were returned from Plainview, TX to Maroa for 22 of the 23 entries. The one entry with a poor response was a very old seed source contributed by Montgomery Consulting. All entries were hand planted in organically managed plots. Conditions since planting have included extreme heat and drought. Supplemental water has been applied and pollinations are being made as this time. Seed was selected for general utility and the best lines and germplasm sources were sent to plant 720 rows in the Puerto Rico nursery in November. This was a substantially greater number of rows than for Montgomery Consulting in the previous winter nursery. The plants grew somewhat unevenly due to moisture stress but approximately 4,000 pollinations were made. One of the major efforts in this winter nursery was to generate hybrid seeds representing inter institutional crosses in a Design II mating scheme. Each collaborator contributed at least one elite male and one elite female. Because of the stand problems and lack of uniform emergence, it was difficult to generate the target amount of seed for each hybrid. Supplies across nurseries were low and the decision was made to hold hybrid seed in reserve until the target could be met. A breeding nursery was planted on the Montgomery Farm in Maroa, IL containing 80 rows in the spring of 2012. Most of these rows were a repeat of the Design II from Puerto Rico. Because of late arriving seed, the nursery was planted very late and into soil which was not uniform in moisture. Stand establishment was erratic and the area is too large and too remote to provide supplemental water in a meaningful way. It will be a challenge to get seed from this nursery. In the spring of 2012, twenty hybrids were sent by Mandaamin Institute to Maroa, IL for observation of disease and insects and agronomics.


Last Modified: 10/24/2014
Footer Content Back to Top of Page