Extension Horticulturist, Texas A&M Research and Extension Center, Stephenville.
Received for publication 2 Apr. 1984. Taken from the MS Thesis of L.A.S. Technical Article no. 19358, Texas Agricultural Experiment Station. Research supported in part by grant by Allied Chemical Corp., Morristown, N.J. Mention of a trademark, proprietary product, or vendor does not imply endorsement by Texas A&M Univ. Trade names were used where common names were not available. 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.