From the Editors. 1

Russell, W.A. Contribution of breeding to maize improvement in the United States, 1920s-1980s. 5

Stockman, Y.M. and R. Shibles. Soybean pod and flower abscission as influenced by carbohydrate supply during flowering. 35

El Mourid, M, G.Q. HE, F.H. Andrade, and I.C. Anderson. Relationship of corn and soybean yields to weekly moving averages for precipitation and temperature at four climatic locations in Iowa. 49

Dekker, J. and W.F. Meggitt. Field emergence of velvetleaf (Abutilon theophrasti) in relation to time and burial depth. 65

Self, H.L. and M. Honeyman. An outlying agricultural research system. 81

Berry, E.C., A.A. Faragalla, L.C. Lewis, and W.D. Guthrie. Effect on diflubenzuron on European corn borer larvae. 91

Clark, L.G. Eight new species of Chusquea (Poaceae: Bambusoideae). 99

Stofferahn, C.W. and P.F. Korsching. Ecological determinants of argarian protest. 123

Barefield, R.L. and C.D. Ziebell. Comparative feeding ability of small white and black crappie in turbid water. 143

Notes. 147

Book Review. 149