Hemp has great potential as cash crop for growers in the US because of its multiple uses in food, pharmaceutical, and industrial products. Seed quality and dormancy research had been put off for decades. The indeterminate flowering pattern of hemp results in harvesting seeds with varying maturity levels, affecting their quality. The objectives of this study were to: 1) investigate the differences in quality of seeds harvested from different locations on the same plant, 2) determine suitable viability and vigor tests for evaluating hemp seeds, and 3) examine the extent of dormancy in newly harvested seeds and develop a dormancy-breaking method. Two hemp varieties, Merlot (ML) and Berry Blossom (BB), which had smaller seeds than ML were evaluated. Seeds from the upper 2/3 part of the plants (more mature) were harvested separately from the lower 1/3 (less mature). The lower part was harvested 7 d after the upper part. Seeds were tested 21 d after harvest. Seed quality was measured by standard germination (SGT), tetrazolium (TZ), accelerated aging (AAT), and speed of germination (SGI) tests. Dormancy was measured in weekly intervals. Difference in seed size did not affect seed quality. Seeds harvested from the upper part of plants had better quality than those from the lower part, however, it became similar to the upper part after 8 d. TZ, SGT, AAT, and SGI were suitable for measuring seed quality. Both varieties had a short-lived dormancy of 35-42 d. Prechilling treatment at 10°C for 5 d was effective in breaking dormancy.
Elias, Sabry G.; Wu, Yea-ching; and Stimpson, David C.
"Seed Quality and Dormancy of Hemp (Cannabis sativa L.),"
Journal of Agricultural Hemp Research: Vol. 2
, Article 2.
Available at: https://digitalcommons.murraystate.edu/jahr/vol2/iss1/2