Effects of Stratification, Warm Treatment, and Mechanical and Acid Scarification on the Emergence of Yellow-Flowered Alfalfa (Medicago sativa subsp. falcata) Seeds

Yellow-flowered alfalfa (YFA) has great potential to improve rangelands in the Northern Plains. Greater than 99% of YFA seeds from soil were viable but less than 4% germinated under standard laboratory conditions. The objective was to determine if low germination was due to physical or physiological seed dormancy. The experiment utilized a random complete block design with two trials, eight replications per trial. Each replication consisted of ten treatments plus a control, four stratification treatments consisting of a combination of two temperatures (-5°C, -20°C) and two durations (48 hr, 72 hr), one warm treatment (4 min, 60°C), four sandpaper scarification treatments with one grade (220) and four durations (2 sec, 4 sec, 6 sec, 8 sec), and one 17-18 M sulfuric acid treatment with duration (30 sec trial 1 and 25 min trial 2). Seeds were planted at the same time in plastic trays filled with potting soil and maintained in a growth room at constant temperature. Tray water content was maintained daily by misting. Number of seedlings, light intensity and temperature were recorded daily for seven days and then every third day for 28 days. Twosample t-test was used to determine the sandpaper scarification treatments significantly increased the final emergence (88%) compared to control (28%) in both trials. Sulfuric acid had a greater final emergence than control. As the duration of the acid treatment increased from 30 sec to 25 min, the emergence increased from 37% to 76%. Results from stratification treatments varied between two trials. There was no significant difference between warm treatment and control for both trials