Acknowledgements
 Our thanks to E. Brown, Agric. Tech. IV, and B.T. Kidd, Biol.
 Sci. II: North Fla. Res. and Educ. Ctr., Univ. of Fla.,
 Quincy,FL; for data collection, computer processing, and data
 illustration.
 References
 Abington, J.B. 1975. Development of a maize breeding program in
 Zambia. I. Evaluation of introduced material and formation of
 Zambia Composite Z. Trop. Agric. (Trinidad) 51:31-38.

 Barnett, R.D., P.L. Pfahler, H.H. Luke, and A.R. Zimet. 1988.
 Florida 303 a new early maturing wheat for North Florida.
 Univ. of Fla., North Fla. Res. and Educ. Ctr., Quincy FL. Res.
 Rep. NF-88-5.

 Herzog, D.C., D.L. Wright, F.M. Shokes, and I.D. Teare. 1988.
 Planting date influence on yield, height, and harvest date of
 selected soybean cultivars. Univ. of Fla., North Fla. Res. and
 Educ. Ctr., Quincy FL. Res. Rep. NF-88-9.

 Jones, D.W., R.A. Dunh, D.H. Teem, F.A. Johnson, and T.C.
 Skinner. 1982. Field corn Production Guide. Fla. Coop. Ext.
 Ser., Inst. of Food and Agric. Sci. Univ. of Fla., Gainesville.
 Cirular 144-F.

 Teare. I.D., D.L. Wright, and D.J. Zimet. 1989. Four years
 experience with tropical corn in a doublecrop system. Univ. of
 Fla.. North Fla Res. and Educ. Ctr., Quincy FL Res. Rep.
 NF-89-4.

.Whitty, B. 1988. History of crop production and rotations used
in North Florida. Univ. of Fla., Dept of Agron., In-service
Training Program "Utilizing crop rotations for profitable
agronomic enterprises", 18-19 Nov. at Quincy FL.

Whitty, E.B. 1974. Soybean recommendations. Fla. Coop. Ext.
Ser. Agronomy Facts 50: 1-2.

Wright, D.L., 1984. Considerations for Multicropping and No-till
Soybeans. Univ of Fla., North Fla. Res. and Educ. Ctr., Quincy
FL. Agron Mimeo.

Wright, D.L., and D.W. Gorbet. 1985. Grain sorghum production
guide. Fla. Coop. Ext. Ser., Inst. of food and Agric. Sci. Univ
of Fla. Gainesville, FL. Circular 346-B.

Wright, D.L., and F.M. Rhoads. 1981. High corn yields with
intensive management. Fla. Coop. Ext. Ser., Univ. of Fla.
Agronomy Facts 116:1-7.

Wright, D.L., F.M. Shokes, M.C. Lutrick, and W.B. Tappin. 1982.
Principle of wheat and no-till soybean production. Fla. Coop.
Ext. Ser., Inst. of Food and Agric. Sci., Univ. of Fla. Circular
506.

Wright, D.L., I.D. Teare, and B.T.Kidd. 1987. Ontogeny of maize
in relation to sequential cropping. Trop.
Agric.(Trinidad)65:169-172.