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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Research Project #432539

Research Project: Managing Selfing Rate in Alfalfa Seed-Production Fields

Location: Vegetable Crops Research

Project Number: 5090-21000-068-05-A
Project Type: Cooperative Agreement

Start Date: Oct 1, 2016
End Date: Jul 31, 2019

The overall goal of this research is to identify management practices that most affect selfing rate in alfalfa seed-production fields. Objective 1 is to gather management practices in each of 10 fields within each of three regions of the Western United States, the Pacific Northwest, and the Central and Imperial Valleys in California, for a total of 30 fields. Objective 2 is to quantify the variation in selfing rate among alfalfa seed production fields. Objective 3 is to estimate plant and flower densities within each field and obtain an estimate of seed yield. Objective 4 is to perform statistical analyses to identify the management practices that most affect selfing rate in alfalfa seed production fields. Objective 5 is to disseminate the results and provide information to the growers and the alfalfa community on selfing rate variation in alfalfa seed production fields and on management practices that minimize selfing rate.

For each field sampled, various characteristics of the seed production field will be noted. These include establishment characteristics; pollination management practices; and other management practices. Approximately 1 week before seed field desiccation 50 plants will be sampled per field. The 50 plants will be chosen randomly from throughout the field, representing 50 different locations. At each location a single seed-bearing stem will be harvested. Leaf tissue will be collected from the stem and preserved in silica gel. Leaf tissue and stems will be shipped to Wisconsin for processing and genotyping. Leaf tissue will be used to genotype the maternal plant of the seeds collected and genotyped on that stem. Eight seeds on each of 40 stems will be randomly selected from each bulk and genotyped using a set of 20 microsatellites developed for alfalfa by ARS. This process will yield 320 seeds and 40 maternal plants genotyped per field. Across all 30 fields a total of 9600 seed and 1200 maternal plants will be genotyped. We will use this information to estimate selfing rate in each of the 30 fields. We will estimate plant and flower density and obtain an estimate of yield from each field. We will also quantify the levels of pest, disease and weed in each field. We will then use statistical methods to determine the management practices most likely to affect selfing rate in alfalfa seed-production fields. We will use this information to design management practices likely to reduce selfing and distribute the information to growers and the alfalfa industry and community.