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United States Department of Agriculture

Agricultural Research Service

Title: Comparative Germination of Different Aged Lots of Eastern Gamagrass Seed in the Greenhouse

Authors
item Krizek, Donald
item Camp, Mary
item Maxon, Susan - AMS
item Davis, Kathleen - NRCS
item Ritchie, Jerry
item McCloud, Miguel
item Cline, James

Submitted to: Proceedings of the 3rd. Eastern Native Grass Symposium
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2003
Publication Date: October 21, 2004
Citation: Krizek, D.T., Camp, M.J., Maxon, S.R., Davis, K.M., Ritchie, J.C., Mccloud, M.L., Cline, J.L. 2004. Comparative germination of different aged lots of eastern gamagrass seed in the greenhouse. In: Randall and J.C. Burns, (eds)Proceedings of the Third Eastern Native Grass Symposium. North Carolina Botanical Garden, Chapel Hill, NC, Oct. 1-3, 2002, Omnipress, Madison, WI. p. 56-62.

Interpretive Summary: Eastern gamagrass is a native, perennial, warm-season bunch grass that has attracted keen interest because of its many attributes. A major obstacle to successful establishment of eastern gamagrass is its erratic germination because of severe dormancy. Earlier studies indicated that 1998 and 1999 lots of seed given a proprietary seed priming treatment showed a decline in germination in the greenhouse and the laboratory within 1 to 6 months. The study was repeated in the greenhouse in 2000 using the same 1998 and 1999 seed lots and a 2000 seed lot to determine the number of days for maximum germination and to establish time-course responses for the three seed lots after various periods of cold storage. Germination tests were conducted in the greenhouse using a peat-vermiculite mix. The average time for maximum germination of 1998 and 1999 seed lots was about 21 days which was 12 days shorter than that for the 2000 seed lot. The time to reach 25 percent germination for the 1998, 1999, and 2000 seed lots was 8 to 9 days for the 1998 and 1999 seed lots and 15 days for the 2000 seed lot. The average percentage germination at 28 days for the 1998 seed lot was 37% which was about 11% higher than for the other two seed lots. These results indicate that: (1) the germination rate of the three seed lots was highly variable; (2) the 2000 seed lot may have developed physiological and/or morphological barriers to germination during seed maturation or that seed priming treatment was not as effective; (3) storage of eastern gamagrass seed in the cold for 2 years had no adverse effect on seed germination; and (4) the length of germination tests for this species can be shortened from 28 to 21 days, thereby saving time and costs. The authors point out that to aid farmers, it would be desirable if the dormant fraction was explicitly included on the seed label (instead of stating a single value for the total percentage of germinated and dormant seed); this would allow one to adjust the planting density to assure a good stand. These findings should be of interest to researchers, farmers, and personnel in seed testing labs.

Technical Abstract: Previous studies indicated that 1998 and 1999 seed lots of Germtec II treated seed of eastern gamagrass [Tripsacum dactyloides (L.) L.] showed a decline in germination in the greenhouse and the laboratory within 1 to 6 months. The study was repeated in the greenhouse in 2000 using the same 1998 and 1999 seed lots and a 2000 seed lot to determine the number of days for maximum germination and to establish time-course responses for the three seed lots after various periods of cold storage at 4oC. Germination tests were conducted in the greenhouse using a peat-vermiculite mix. All three seed lots showed a mid-season suppression of germinability. The average times for maximum germination of 1998 and 1999 seed lots were comparable, viz., 20.5 and 21.6 days, which was shorter than that for 2000, viz. 33.3 days. The time to reach 25 percent germination for the 1998, 1999, and 2000 seed lots was 8.1, 9.2 and 15.0 days, respectively, and the average percentage germination at day 28 for the three seed lots was 36.8, 25.6 and 26.4, respectively. These results indicate that: (1) the germination rate of the three seed lots was highly variable; (2) the 2000 seed lot may have developed physiological and/or morphological barriers to germination during maturation or that seed priming treatment was not as effective; (3) a long period of storage time for the 1998 seed lot did not have an adverse effect on germination results; and (4) 21 d is sufficient for a germination test in this species.

Last Modified: 12/22/2014
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