Assistant Research Scientist, Yuma Mesa Agricultural Center, Univ. of Arizona, Route 1, Box 40-M, Somerton, AZ 85350.
Professor, Dept. of Agronomy and Horticulture.
Received for publication 23 June 1986. New Mexico Agricultural Experiment Station Journal Series no. 1199. Part of a thesis submitted by J.J.M. in partial fulfillment of the MS degree requirement of New Mexico State Univ.