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United States Department of Agriculture

Agricultural Research Service

Related Topics

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

2013 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 (2,500 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 three 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% 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 ten 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:
Montgomery Consulting efforts so far have created breeding lines as follows: high yielding as inbreds per se; elevated protein, methionine, lysine, and carotenoids; potential for efficient nitrogen use, drought tolerant; resistance to multiple insect pests; designated for use as females and have above average leaf disease and stalk rot resistance. Such lines were developed from proprietary breeding populations. Eight segregating breeding populations [synthetics] were sent to Ames, Iowa, Lake Geneva, Wisconsin, Ithaca, New York, and Las Cruces, New Mexico for cooperative population trials. These populations are superior for developing inbreds and improved germplasm sources and 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 ARS for cooperative testing. Those populations are being compared with populations from Montgomery Consulting on each site, including a randomized, complete block experiment in Maroa, Illinois managed by Montgomery Consulting. Because of periods of extended rain, tests were planted late. Stands are inconsistent, but unlike last year, water is not currently limiting. 22 germplasm sources were screened for cold shock characteristics. Cornell sent five; Mandaamin Institute sent ten; USDA sent one and Montgomery Consulting contributed six. At least 250 responsive seedlings were returned from Plainview, Texas to Maroa, Illinois for 21 of the 22 entries. Mandaamin Institute’s ten entries were returned for transplanting in Wisconsin. All cold shock entries were hand planted in organically managed plots. Conditions in Illinois since planting have included extreme cool and extreme heat with abundant moisture. Pollination preparation (shoot bagging) is currently underway. The cooperator went to Puerto Rico three times to supervise and coordinate winter nursery activities: November-December 2012 to plant; January – February 2013 to pollinate; and April 2013 to harvest, shell and ship seed. Seed was selected for general utility and the best lines and germplasm sources were sent to plant 784 rows in the Puerto Rico nursery in November 2012. This was essentially the same number of rows compared to Montgomery Consulting in the previous winter nursery. Stand establishment was poor due to low soil moisture at planting, but approximately 250 pollinations were made by the cooperator and pollinating crew. One of the major efforts in the Puerto Rico winter nursery was to generate seed of hybrids 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 seed target could be met. A breeding nursery was planted on the Montgomery Farm near Maroa, Illinois in the spring of 2013. Stands are mostly adequate. Most of these rows were a repeat of the Design II from Puerto Rico. Also included are: a selected sample (54 rows) of elevated oleic acid inbreds and hybrids; 14 germplasm accessions from Mandaamin Institute for evaluation in a more southern environment; 50 additional germplasm sources, including native herbicide tolerance. Of primary concern is information on the combining ability of those 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. Toward that goal, an isolation was planted to generate approximately 300 hybrids in the summer of 2013. The isolation male is a food grade, yellow grain, white cob inbred with very good general combining ability, in the non-SS heterotic pattern. Females include proprietary lines with native resistance to multiple insect pests; drought tolerance; improved nutritional profiles, and improved yield of the inbred in seed production systems. To assist in the calibration of the Near Infrared (NIR) for elevated protein and other essential amino acids, 425 seed samples of various pedigrees and suspected chemical composition profiles were submitted to the Grain Quality Lab at Iowa State University. NIR data were returned for 406 entries.

4. Accomplishments

Last Modified: 10/17/2017
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