GERMINATION OF ALFALFA VARIETIES IN SOLUTIONS OF VARYING OSMOTIC PRESSURE AND RELATIONSHIP TO WINTER HARDINESS

Abstract

Two laboratory experiments were conducted to evaluate the reliability of amount of germination in solutions of varying osmotic pressure, as a means of separating alfalfa varieties into winter-hardiness classes. In one test 23 varieties or strains were studied, and in the other 36. It was found that significant differences exist between certain alfalfa varieties in their ability to germinate in sucrose or sodium chloride solutions of 3, 6, and 9 atmospheres. There is a general tendency for non-hardy varieties to germinate more rapidly and more completely than hardy ones but there are many exceptions to this trend. Germination in solutions of 6 atmospheres osmotic pressure at 5 days gave the best separation of varieties on the basis of their ability to germinate. Germination was generally better in solutions of sucrose at 6 atmospheres osmotic pressure than in solutions of sodium chloride of the same osmotic pressure but several varieties germinated equally well in either solution. The results indicate that germinating alfalfa in sugar or salt solutions is not a reliable method for differentiating alfalfa varieties into winter hardiness classes.