Received for publication 20 Aug. 1982. Paper of the Journal Series, New Jersey Agricultural Experiment Station. Research performed as a part of NJAES Project No. 12143, supported by New Jersey Agricultural Experiment Station, Hatch Act Funds. Dept. of Horticulture and Forestry, Cook College, Rutgers Univ., New Brunswick. NJ 08903. 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.