2. Attempts to shorten corn plants for convenience in pollination were not entirely successful. Two single crosses (Hy × L317 and Hy × 540) planted at two different times, May 27 and June 8, were bent to the ground and tied with binder twine to the adjoining plant on July 14. At this time the first planting was 3-4 feet and the second planting about 2 feet high. The plants were about one foot apart in the row. All of the plants had such a strong pull toward tho erect position that all were injured to a certain extent by the string cutting into the stalks. Some plants were completely severed below the growing point and thus committed suicide rather than be tied down! Short plants were tied above the growing point. These bowed upwards between the base and place of attachment and tried to grow out of the leaf sheaths and were badly stunted. The treated plants in both plantings were shortened about 15 inches in ear height. The first planting was shortened 22 inches in average height of stalk to tip of tassel and the second planting 11 inches. The treated plants were also delayed a day or two in time of tasseling and silking. Both pollen and seed production were seriously reduced by this treatment. Possibly the plants can be tied more loosely using a larger and softer cord. Care must be taken to tie the plants well below the growing point.
Plants that were bent over and covered with soil straightened out and were not reduced in height or delayed in flowering. Plants with half of each leaf cut off before flowering were not shortened in height but were so delayed in flowering that many of them never produced either tassels or ears!
Plants grown from seeds in which the embryo was cut out and attached to endosperms of the same or different genetic constitution were kept in the greenhouse for several weeks and later set in the field. Compared with untreated plants of the same type these plants were noticeably shortened. Since other plants grown for an equal length of time in the greenhouse were not shortened it may be that the embryo excision had something to do with this change.
D. F. Jones