10. Stalk lodging in inbred lines of corn caused by 2,4‑D spray during flowering.

Spraying inbred lines of corn with 2,4‑D solution during flowering caused extreme differences in lodging. The material included 160 inbred lines from 15 states and the United States Department of Agriculture. Most of these lines are widely used in the hybrid corn programs in the Corn Belt.

The plants were sprayed with one‑half pound of amine acid in 100 gallons of water per acre. The application was made with a small hand sprayer on July 13, 1948, when most of the lines were tasseling.

Each plot consisted of two hills with three plants per hill. Two plots of each line were sprayed, making a total of four hills or 12 plants per line. On July 24, the plants were graded for lodging. The amount of lodging was graded as follows:

a. No lodging

b. Light lodging

c. Average lodging

d. More than average lodging

e. Very bad lodging.

A difference of 1.5 grade between any two lines was significant at the one per cent level. The following lines graded 2 or less and were most resistant to lodging: A111, A116, A158, A12, A340, A334, Os420, Hy2, K63, Kys, K201C, B10, and CI.21E. The following lines graded 5 and lodging badly: A7, Os426, L289, Ind. H5, Mo2RF, Iowa 159, Ind. 33‑16, Ky 39, Ky 58, CI.187‑2, K148 and CI.5.

The land was free of weeds at the time of spraying. The application, however, fairly well controlled the weeds that came up after the application of 2,4‑D spray. It is believed that this type of application might be valuable in controlling weeds that often appear after pollination in breeding or genetic nurseries.

R. W. Jugenheimer and

F. W. Slife