Agronomy Mimeo. No. 4
March, 1940
Comparisons of Seed Corn of Different Degrees of Maturity 1/
S.R. Miles

In 1938 a study was begun to learn the value of seed corn of different degrees of maturity.
Seed of Indiana hybrid 610, (AxL)(Wf9xHy), was obtained, from an area 120 feet long and 6 seed rows wide in the seed field. This area was divided into 24 blocks each 10 feet long by 3 seed rows wide. Seven harvests were made at intervals of one week beginning September 2, 35 days after the ear shoots on half of the seed plants showed silks. An 8th harvest was made 2 weeks after the 7th. At each harvest one ear was taken from each of the 24 small blocks in the seed field.
At harvest there was an average of 53.4 per cent water in the kernels of the 24 ears in the first harvest. For the 4th harvest the percentage was 32.7 and for the 8th harvest 14.2. Earlier research by the writer indicates that corn reaches maturity when the kernels contain about 33 per cent water (or the ears contain about 38 per cent water). . On this basis the seed from the 4th harvest just matured.
Within 2 hours after harvest the ears were put into an electric oven and were dried to 12 per cent water at 110 degrees Fahrenheit. They later dried to 5.0 to 8.0 per cent water from storage in a warm room with dry air.
Table 1 presents data from laboratory work.
In .193.9 seed of the first 6 harvests was planted in the field. Data were secured relative to rapidity of emergency of seedlings from the soil, rapidity of growth, stands obtained, and yield. These data are in Table 2.
To study (1) rapidity of emergence and (2), stands, a planting was made May 1, while the soil was still cold, and another May 25, after the soil was relatively warm. Both treated and untreated seed were used. The treatment was an organic mercury compound dust. June 24, when t he soil was very warm, a planting was made to study rapidity of emergency and of growth.
Experiments were planted May 24 to study the yields from treated and untreated seed. In order to obtain about the same stands from seed of each harvest, the seed of the first 3 harvests was planted at the rate of 3 kernels per hill in some plots and 4 kernels per hill in other plots. Later harvests were planted at 3 per hill only. The plots were 2 by 10 hills, and hills were 42 by 42 inches. The average yield from seed of each harvest was determined from 32 or 22 plots.
1/ The data in columns 4 to 13 of Table 1 are from a thesis by Ray A. Burger for the degree of Master of Science in Agriculture.
The Agronomy Department, in cooperation with the Department of Botany, Purdue University Agricultural Experiment Station, and with the Division of Cereal Crops and Diseases, Bureau of Plant Industry, U. S. Department of Agriculture,
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