Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School



Plant breeders interested in hybrid sorghum in the past few years have initiated intensive improvement programs whereby two or three generations of breeding stock may be grown each year. To accomplish this, seed must be harvested as early as is possible, dried immediately, and planted within a few weeks after harvest. During routine testing of these freshly harvested and dried seeds, many samples were found which did not give satisfactory germination results. The low germinating samples were checked with a triphenyl tetrazolium chloride solution to determine their potential viability. The tetrazolium test indicated the seed was 100 percent viable. This evidence pointed to the fact that these samples were in a temporary state of dormancy. The same samples tested a few months after harvest gave satisfactory germination. Similar difficulty has been encountered at the South Dakota Seed Laboratory. The Agronomy Seed Laboratory tests all samples for the Seed Certification Service. These tests determine whether or not the samples submitted for certification meet the certification standards for purity and germination. The minimum certification standard for germination of Sorghum vulgare Pers. seed is 80 percent (2). The Agronomy Seed Laboratory obtained many germination percentages below this standard during routine testing of sorghum samples for the Certification Service. This was especially evident for the forage sorghums. Further testing with a tetrazolium salt solution showed the samples had a much higher potential germination. Dry storage of these same samples in the laboratory for three to four months gave germinations comparable to the tetrazolium results. A special treatment for fresh and dormant seed, recommended by the Association of Official Seed Analysts in the publication Rules for Testing Seeds (1), had no beneficial effect on the germination of these dormant lots of seed. This study was undertaken to determine if dormancy is present in the grain and forage sorghums. It was also desired that a reliable method for breaking dormancy could be devised for use in testing dormant samples of sorghum at the Agronomy Seed Laboratory.

Library of Congress Subject Headings



Includes bibliographical references



Number of Pages



South Dakota State University