Varietal changes in two Finnish alsike clover varieties grown for seed in the USA

Authors

• Otto Valle Department of Plant Husbandry, University of Helsinki
• Kirsti Äyräväinen Department of Plant Husbandry, University of Helsinki
• C. S. Garrison Plant Science Research Division, Agricultural Research Service, U. S. Department of Agriculture

DOI: https://doi.org/10.23986/afsci.71832

Abstract

Two Finnish alsike clover varieties, diploid Tammisto and tetraploid Iso, were grown for seed at different locations in the USA for several successive generations. The seed lots were tested in single-plant and forage production trials in Finland to reveal possible varietal changes caused by producing seed in foreign environments. Many of the Tammisto alsike lots produced in the USA had more early-type plants than the Finnish basic seed. In contrast the USA grown Iso lots which differed from the basic seed had lower average growth type indices and fewer flowering plants. Increase in earliness was supposed to result from efficient pollination during early, sparse flowering, decrease in earliness from the fact that alsike clover is a species especially prone to shedding its seeds as soon as they mature. In spaced-plant tests many of the USA lots produced progenies with less winterhardiness than those from the basic seed lot. The poorest overwintering was recorded for the lots from the southern locations. There were no appreciable differences between the four production localities in the United States in terms of other characteristics of the two varieties. – With successive generations of increase no progressive varietal changes were found to occur. Seed lots harvested from the same plot for two or more years did not differ from each other. Forage yield trials comparing the most advanced generation seed lots from the USA with basic seed did not reveal any consistently significant differences.