Control of Sex Reversal in the Tassel of Indian Corn

Narrow-grain Evergreen sweet corn is decidedly influenced in its sexual expression by the length of the daily illumination period, and the amount and degree of reversal to femaleness in the tassel is subject to experimental control. Limited experiments with Country Gentleman sweet corn indicate that the same condition is present in that variety. 2. Corn planted on November 1 in the greenhouse will, with proper substratum and heat, show 100 per cent of the individuals with some degree of female expression in the tassel, while that planted in the spring or summer will normally show only pure staminate tassels. 3. Corn planted either before or after this date, under similar conditions, will show a ratio of sex reversal inversely proportional to the length of the daylight. With the approach of equal day and night periods of 12 hours each, little or no reversal will occur in the tassel. 4. The time and point of female sex determination can be thrown back to the second or third leaf nodes from the base of the plant. 5. Whenever the female state is established in the main stem, either above or below the point of lateral ear development, the internodes become decidedly flexuous, and in extreme cases they are even thrown into loops. 6. Any plot of corn, grown in the greenhouse, can be so planted and developed that the individuals of the population will show every gradation, from the normal monoecious type, with pure carpellateness expressed in the side branches and pure staminateness in the terminal inflorescence, to an absolutely pure female condition, all the flowers of the terminal inflorescence as well as those of the lateral ears being purely carpellate.