Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)




Green needlegrass (Stipa viridula Trin.) in the past few years has received wide acceptance for use in range renovation throughout the Northern Great Plains. Maximum germination of newly harvested green needlegrass seed cannot be obtained due to a high incidence of seed dormancy. This study was undertaken to determine the nature of dormancy present in green needlegrass seeds, to study the mode of expression of factors that causes dormancy in the seeds, and to seek a method which will reduce the dormancy in order to obtain maximum germination readings in the laboratory and in field plantings. Seed dormancy was found to be the main cause of low germination of green needlegrass, both in the laboratory and in the field. Dormancy was present in the seeds of green needlegrass each year this study was conducted. Maturity studies conducted indicate dormancy is present in green needlegrass seeds in the immature stage of maturity as well as in the fully mature stage. Two types of dormancy were found to be present in green needlegrass: an external restriction and a chemical block within the seed. The special treatment for germination of green needlegrass seed prescribed by the Subcommittee on range Grasses of the Association of Official Seed Analysts did not entirely break this dormancy. Limited germination increases were obtained by removing the glumes, puncturing seed coats, and clipping the tip of the caryopsis, and also by mechanical and acid scarification.

Library of Congress Subject Headings



Includes bibliographical references



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