SECTION XVIII. PLANT SEEDING
In propagating by seed, as in reproducing by buds, we select a portion of the parent plant—for a seed is surely a part of the parent plant—and place it in the ground. There is, however, one great difference between a seed and a bud. The bud is really a piece of the parent plant, but a piece of one plant only, while a seed comes from the parts of two plants.
You will understand this fully if you read carefully Sections XIV-XVI. Since the seed is made of two plants, the plant that springs from a seed is much more likely to differ from its mother plant, that is, from the plant that produces the seed, than is a plant produced merely by buds. In some cases plants "come true to seed" very accurately. In others they vary greatly. For example, when we plant the seed of wheat, turnips, rye, onions, tomatoes, tobacco, or cotton, we get plants that are in most respects like the parent plant. On the other hand the seed of a Crawford peach or a Baldwin apple or a Bartlett pear will not produce plants like its parent, but will rather resemble its wild forefathers. These seedlings, thus taking after their ancestors, are always far inferior to our present cultivated forms. In such cases seeding is not practicable, and we must resort to bud propagation of one sort or another.
While in a few plants like those just mentioned the seed does not "come true," most plants, for example, cotton, tobacco, and others, do "come true." When we plant King cotton we may expect to raise King cotton. There will be, however, as every one knows, some or even considerable variation in the field. Some plants, even in exactly the same soil, will be better than the average, and some will be poorer. Now we see this variation in the plants of our field, and we believe that the plant will be in the main like its parent. What should we learn from this? Surely that if we wish to produce sturdy, healthy, productive plants we must go into our fields and pick out just such plants to secure seed from as we wish to produce another year. If we wait until the seed is separated from the plant that produced it before we select our cotton seed, we shall be planting seed from poor as well as from good plants, and must be content with a crop of just such stock as we have planted. By selecting seed from the most productive plants in the field and by repeating the selection each year, you can continually improve the breed of the plant you are raising. In selecting seed for cotton you may follow the plan suggested below for wheat.
Figs. 49 and 50. Chrysanthemums and Asparagus
The difference that you see between the wild and the cultivated chrysanthemums and between the samples of asparagus shown in Figs. 49 and 50 was brought about by just such continuous seed-selection from the kind of plant wanted.
Fig. 51. Two Varieties of Flax From One Parent Stock
By the careful selection of seed from the longest flax plants the increase in length shown in the accompanying figure was gained. The selection of seed from those plants bearing the most seed, regardless of the height of the plant, has produced flax like that to the right in the illustration. These two kinds of flax are from the same parent stock, but slight differences have been emphasized by continued seed-selection, until we now have really two varieties of flax, one a heavy seed-bearer, the other producing a long fiber.
You can in a similar way improve your cotton or any other seed crop. Sugar beets have been made by seed-selection to produce about double the percentage of sugar that they did a few years ago. Preparing and tilling land costs too much in money and work to allow the land to be planted with poor seed. When you are trying by seed-selection to increase the yield of cotton, there are two principles that should be borne in mind: first, seed should be chosen only from plants that bear many well-filled bolls of long-staple cotton; second, seed should be taken from no plant that does not by its healthy condition show hardihood in resisting disease and drouth.
The plan of choosing seeds from selected plants may be applied to wheat; but it would of course be too time-consuming to select enough single wheat plants to furnish all of the seed wheat for the next year. In this case adopt the following plan: In Fig. 52 let A represent the total size of your wheat field and let B represent a plat large enough to furnish seed for the whole field. At harvest-time go into section A and select the best plants you can find. Pick the heads of these and thresh them by hand. The seed so obtained must be carefully saved for your next sowing.
Fig. 52.
In the fall sow these selected seeds in area B. This area should produce the best wheat. At the next harvest cull not from the whole field but from the finest plants of plat B, and again save these as seed for plat B. Use the unculled seed from plat B to sow your crop. By following this plan continuously you will every year have seed from several generations of choice plants, and each year you will improve your seed.
It is of course advisable to move your seed plat B every year or two. For the new plat select land that has recently been planted in legumes. Always give this plat unwearying care.
In the selection of plants from which to get seed, you must know what kind of plants are really the best seed plants. First, you must not regard single heads or grains, but must select seed from the most perfect plant, looking at the plant as a whole and not at any single part of it. A first consideration is yield. Select the plants that yield best and are at the same time resistant to drouth, resistant to rust and to winter, early to ripen, plump of grain, and nonshattering. What a fine thing it would be to find even one plant free from rust in the midst of a rusted field! It would mean a rust-resistant plant. Its offspring also would probably be rust-resistant. If you should ever find such a plant, be sure to save its seed and plant it in a plat by itself. The next year again save seed from those plants least rusted. Possibly you can develop a rust-proof race of wheat! Keep your eyes open.
In England the average yield of wheat is thirty bushels an acre, in the United States it is less than fifteen bushels! In some states the yield is even less than nine bushels an acre. Let us select our seed with care, as the English people do, and then we can increase our yield. By careful seed-selection a plant-breeder in Minnesota increased the yield of his wheat by one fourth. Think what it would mean if twenty-five per cent were added to the world's supply of wheat at comparatively no cost; that is, at the mere cost of careful seed-selection. This would mean an addition to the world's income of about $500,000,000 each year. The United States would get about one fifth of this profit.
It often happens that a single plant in a crop of corn, cotton, or wheat will be far superior to all others in the field. Such a plant deserves special care. Do not use it merely as a seed plant, but carefully plant its seeds apart and tend carefully. The following season select the best of its offspring as favorites again. Repeat this selection and culture for several years until you fix the variety. This is the way new varieties are originated from plants propagated by seed.
In 1862 Mr. Abraham Fultz of Pennsylvania, while passing through a field of bearded wheat, found three heads of beardless, or bald, wheat. These he sowed by themselves that year, and as they turned out specially productive he continued to sow this new variety. Soon he had enough seed to distribute over the country. It became known as the Fultz wheat and is to-day one of the best varieties in the United States and in a number of foreign countries. Think how many bushels of wheat have been added to the world's annual supply by a few moments of intelligent observation and action on the part of this one man! He saw his opportunity and used it. How many similar opportunities do you think are lost? How much does your state or country lose thereby?
EXERCISE
Select one hundred seeds from a good, and one hundred from a poor, plant of the same variety. Sow them in two plats far enough apart to avoid cross-pollination, yet try to have soil conditions about the same. Give each the same care and compare the yield. Try this with corn, cotton, and wheat. Select seeds from the best plant in your good plat and from the poorest in your poor plat and repeat the experiment. This will require but a few feet of ground, and the good plat will pay for itself in yield, while the poor plat will more than pay in the lesson that it will teach you.
Write to the Department of Agriculture, Washington, D.C., and to your state experiment station for bulletins concerning seed-selection and methods of plant-improvement.