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Show Apple Trees of the Future May Grow on Their Own Roots, Nursery Expert Says When the cuttings are made In the fall it is only necessary to remove the shoot, strip off the tape or paper tube, make the basal cut in the etiolated eti-olated area, and set it out. Why etiolation should favor the production produc-tion of roots on stem tissue is as much "in the dark" as the process itself, says Doctor Gardner. Several practical advantages are seen for the process, mainly in that it is easier and cheaper to make a cutting than a graft. One man can wrap several thousand shoots in one day. Too, there is a possibility of avoiding variability common in root stocks of grafted apple trees. In many cases, however, it is more desirable to grow apple trees on roots other than their own. Some varieties have root systems that lack cold hardiness and are susceptible sus-ceptible to disease and insect attacks. at-tacks. The propagation of such va-rieties va-rieties on their own roots would not be desirable. Apple trees of the future may grow on their own roots. In the past the apple tree was an assembled assem-bled article with the fruit-producing part grafted to a common root stock such as the French crab variety. This was necessary because seedlings seed-lings do not produce true to variety, and because cuttings of stem tissues would not take root. Now scientists of the United States Department of Agriculture have developed a method by which stem cuttings of apple varieties are induced to form root initials or points of origin on the stem that promptly develop into roots when the cuttings are taken from the tree and set in the soil, thus doing away with grafting. The process is described by Dr. F. E. Gardner, in charge of nursery stock investigations for the bureau of plant industry, as "etiolation." The growing shoot is wrapped in black tape when it starts to put out leaves in the spring. A piece 24 to 3 inches long is sufficient to wrap four or five times spirally around the young shoot as near the growing tip as possible. Another method is to place a small black paper tube over the shoot. All growth is made in complete, or nearly complete, absence of light. |