U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Date of this Version
3-2017
Citation
ANNUAL REPORT OF THE BEAN IMPROVEMENT COOPERATIVE, No. 60, March 2017. Published by USDA.
Abstract
The Seedling Straw Test is a modified version of the Petzoldt and Dickson (1996) straw test. Most steps are similar, including using normal clear or colored straw segments and production of the pathogen culture. The main difference between the two tests is in the stage of inoculation and the scoring system. Timing of mycelia production is more critical in this test compared to the standard straw test as there is a very narrow window for inoculation. The test can be can be completed within 25 days whereas the original straw test requires at least 35 days. Fewer resources (potting media, bench space) and less labor are required for the seedling straw test.
The Seedling Straw Test procedure is as follows:
Plant seeds in eight to 12 cm pots with one seedling per pot (plant 2-3 seeds and thin to one at emergence) or multiple seedlings in larger pots may be grown. Because plants remain small by the time the test is completed, there is no need to use large pots unless plants will be retained for seed.
Immediately after all seeds are germinated and emerged, prepare the inoculum. Growing the pathogen in petri dishes on PDA is exactly same as with conventional method but seedling growth must be judged carefully so that the pathogen culture is ready at the right stage of plant growth.
Comments
U.S. government work.