Influence of low temperature treatments on the germination of seeds of sweet clover and smooth vetch

• Published in: Journal - American Society of Agronomy Vol. 31; no. 8; pp. 687 - 694
• Main Author: Dunn, L.E
• Format: Journal Article
• Language: English
• Published: 1939
• Subjects: melilotus alba; seed germination; seed treatment; temperature; Vicia villosa
• ISSN: 0095-9650; 2690-9162

A number of experiments were conducted with locally-grown seed samples of sweet clover and smooth vetch to find the influence of various low temperature treatments and alternating temperatures on the softening of hard seeds and on the germination of seed samples. The various treatments consisted of moist and dry storage of seed samples under the following conditions: Room temperature; 5 degrees C; -10 degrees C; -10 degrees C for 1 week followed by continuous storage at 5 degrees C; alternations in weekly intervals between temperatures above and below freezing. Storage periods ranged from 1 to 10 months. At the close of a storage period for a sample, dead seeds and seed which had produced radicles more than 1 cm in length were discarded. The remainder of the sample was tested for germination. No low temperature storage treatment was found which would cause seed samples of sweet clover and smooth vetch to give higher germination percentages than seed samples which had been stored dry at room temperature. Moist storage of the seed samples under the various low temperature and alternating temperature conditions was found to be harmful to germination. Permeable seeds produce radicles slowly in low temperature storage slightly above freezing. Permeable seeds which had absorbed enough water to be slightly swollen were injured or killed by freezing. Dry storage of seed samples under the same conditions was observed to have no significant influence on germination. The various moist and dry storage treatments were observed to have no significant influence on the softening of hard seeds of sweet clover after storage periods ranging from 1 to 10 months. The various moist storage treatments were observed to be effective in the softening of hard seeds of smooth vetch. Samples of 200 hard seeds each were given the treatments. After 6 months storage only approximately 20% of the original hard seeds were still impermeable. In all cases hard seeds which had softened germinated normally when they were not frozen after taking up water. These results would indicate that probably the majority of hard seeds of smooth vetch would germinate and produce plants within the first 2 or 3 months after planting.