The quality of alfalfa seed as affected by color and plumpness

Laboratory studies have established that there is a considerably higher germination of alfalfa seeds on blotters than occurs in soil in the laboratory as measured by emergence through 3/8 inch of sandy loam soil. When germinated in soil there was progressively poorer germination for greater and greater degrees of discoloration in the seed. Bright olive green seeds were highest with an average of 65.1%, whereas shriveled brown seeds were poorest with a germination of 18.7%. Scarification increased the total germination about 10 to 15%, but affected the brighter colored seeds the most. However, there was a total of 10.7% weak and moldy sprouts from scarified seeds as compared with 5.3% from unscarified. Tests conducted in the field repeated the laboratory tests except that instead of seven color separates used in the laboratory only three were used in the field. The color separates for field seeding were so made as to compare with the laboratory separates. Germinations in the field as measured by emergence were considerably lower in the field than under laboratory conditions when seeded at about the same depth. Bright plump seeds gave 67.2% in the laboratory and 48.8% under field conditions. From 75 to 80% of the plants which emerged in the field established themselves and grew for some weeks. Bright-colored seeds were found to be 38% more effective in the field than were bulk (check) seeds from the same lot, while in the laboratory the difference was 22%. Field plat experiments devoted to seed production also yielded valuable data regarding the percentages of discolored seeds produced. Significant increases in discolored seeds were found in the seeds produced from plats on which the seed crop was allowed to start late. This was accomplished by growing a hay crop before the growth from which seed was to be taken was allowed to start. The manner of harvest, the nature of field tillage, the sort of irrigation treatment, or the time of clipping the preceding growth (save for over-late clipping), all produced seed of the same color within the limits of error variations.