1Received for publication February 17, 1981.
The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.
This paper reports the results of research only. Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the U. S. Department of Agriculture and does not imply its approval to the exclusion of other products or vendors that may also be suitable.
Research supported in part by State, Hatch and USDA funds allocated to the Georgia Agricultural Experiment Stations.
2U. S. Department of Agriculture, Science and Education Administration, Agricultural Research, Tifton, Ga. 31793.
3University of Georgia College of Agriculture Experiment Stations, Tifton. Ga. and Athens, Ga., respectively.