Former Research Assistant. Presently Assistant Professor, Department of Agronomy and Horticulture, Brigham Young University, Provo, UT 84602.
Research Plant Physiologist and to whom reprint requests should be addressed.
Received for publication June 11, 1982. Published as Technical Paper No. 6398, Oregon Agricultural Experiment Station. Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the USDA and does not imply approval to the exclusion of other products or vendors that may also be suitable. The authors thank D.M. Burdic and J.M. Rasmussen for their excellent technical assistance. 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.