Results of the Cooperative Uniform Soybean Tests, 1946 Part I. North Central States

United States Department of Agriculture, Agricultural Research Administration; Bureau of Plant Industry, Soils, and Agricultural Engineering, Division of Forage Crops and Diseases Cooperating with State Agricultural Experiment Station

Results of the Cooperative Uniform Soybean Tests, 1945. Part I. North Central States

United States Department of Agriculture Agricultural Research Administration Bureau of Plant Industry, Soils, and Agricultural Engineering, Division of Forage Crops and Diseases Cooperating with State Agricultural Experiment Station

Growth Abnormalities Resulting in Premature Death of Nursery Grown Sweetclover Plants

The effects of temperature, soil moisture, humidity, and fertilizers along with other environmental factors can alter the host plant and thereby influence its resistance to disease. This thesis reports on some relatively easily observed gross changes in nursery-grown sweetclover which have a marked effect on the ability of the plants to withstand invasion of root-rotting organisms.The most striking of these changes is the growth of the roots to enormous size (giantism) as a result of very early seeding and the absence of plant competition in the widely-spaced plant breeding nursery. The practical significance of this study is that to help control root-rot disease, the plants were grown in a manner so that they will not develop excessively during their first year of growth. In the 1941-42 breeding nursery this was accomplished by starting the spaced plants late in the season. Due to the ease with which resistance to disease can be increased or decreased, it is suggested that sweetclover might serve as useful plant material in studies on the influence of biochemical and anatomical characters on degeneration and susceptibility to disease. Advisor:T.A. Kiesselbac