Received for publication January 12, 1974. This paper is based on a dissertation submitted by the senior author in partial fulfillment of the requirements for the Doctor of Philosophy degree in Horticulture, The Pennsylvania State University. Authorized for publication on October 29, 1973 as paper no. 4559 in the Journal Series of the Pennsylvania Agricultural Experiment Station.
Present address. Plant Physiologist. Virginia Truck and Ornamentals Research Station, Virginia Beach, VA.
Associate Professor of Plant Breeding, Department of Horticulture.
This research was conducted under a National Science Foundation Traineeship.
The authors express appreciation to Orlando Pride, Butler, PA for providing plant materials for this research.