Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School



Switchgrass (Panicum virgatum L.), a warm-season grass native to North America, is distributed from Canada to Central America anu from the Atlantic Coast to Nevada over a wide range of habitats. It exhibits tremendous promise for forage and soil conservation utilization in the Great Plains and True Prairie regions. The economic value of switchgrass as summer forage has long been recognized and its potential for improved variety production is great due to extensive ecotypic genetic variability and relatively good seed quality and production. A full season pasture system comprised of separate pastures of cool and warm-season species offers maximum beef production efficiency, and switchgrass was found to yield the most beef gain per hectare of the major tall, warm-season grasses native to South Dakota. Poor seedling vigor and inconsistent seed production have severely limited the widespread use of switchgrass. Kneebone and Cremer determined that selecting for seed size in switchgrass was an effective method for improving seedling vigor. Improved vigor results in quick germination and rapid seedling development, consequently increasing the chance of stand survival if a stress period is encountered during establishment. Cornelius concluded native warm-season grasses were especially poor seed producers. Seed yield components need to be examined to identify those which have the greatest influence on seed yield. Identification of the important seed yield components wou1d faci1itate selection for specific characteristics resulting in improved seed yield. With improvements in seedling vigor and seed yield, switchgrass could make a substantial contribution to the total carrying capacity of full season pasture systems. The objectives of this study were (1) to determine variation for seed size within and among three switchgrass varieties grown in the same environment, (2) to identify an easy and accurate method for separating different seed weight fractions from bulk seedlots, (3) to determine the effect of weight of parent seed on seedling vigor and mature plant forage and seed characters, and (4) to evaluate, by employing multiple regression and path coefficient analysis, the relative contributions of four seed yield components to total seed yield of individual plants.

Library of Congress Subject Headings

Grasses -- Seeds

Grasses -- South Dakota

South Dakota State University Theses

Panicum virgatum L.



Number of Pages



South Dakota State University