Similar groups of valuable intermediate types of fruits have been produced by Dr. Saunders, the Director of the Canadian Experimental Farms, by crossing varieties of the ordinary apple, such as the Pewaukee and Wealthy, with a very hardy cold-resistant crab (Pyres baccata). Dr. Saunders has produced already numerous hardy intermedi ate types which bid fair to be of very great economic value.
(3) The combination of different parental characters not blended.
The greatest value of hybridization in the pro duction of new varieties lies probably in the possi bility of combining in the new race certain valu able characters of different races or species. This principle breeders have long recognized, but it cannot be too clearly borne in mind. The work which the writer has carried out in the Department of Agriculture, in the production of long-staple varieties of upland cotton, forms an interesting illustration in point. Ordinary upland cotton, which is grown all over the interior cotton regions of the South. produces a short fiber averaging about one inch in length. In the eastern part of South Carolina, southern Georgia and northern Florida, sea island cotton is grown. This cotton has a fiber 1 to Dr inches in length. Ordinary up land cotton has an average value of eight or nice cents per pound, while this longer staple sea island cotton is ordinarily worth twenty to thirty cents per pound. Other things being equal, a longer fibered cotton is always more valuable than a short staple, and were it possible to secure the same yield it would be far better to grow long-staple cotton altogether. The sea island or long-staple cotton, however, has a small three-locked boll which opens very poorly, and is difficult to pick, and yields much less than does upland cotton. Up land cotton, on the contrary, produces large rounded bolls, which open wide and are easy to pick, and yields much more heavily than the other. Sea island cotton has a smooth black seed, so that rol ler gins can be used in separating the seed and fiber, and this is an important consideration with long-staple cotton, as the saw-gin tears and breaks the fiber. With the short-staple or upland cottons the seed is covered with a short close fuzz, and they are uniformly ginned on saw-gins. The tear ing of the fiber which necessarily results to a con siderable extent, does not matter greatly with a fiber of this short length. If longer stapled varie ties are desired they should have smooth, black seed, so that a roller gin can be used. The writer under took experiments in the hybridization of these two kinds of cotton, in the hope of producing a new race, which would inherit, on the one hand, the large bolls, tendency to yield heavily, and adapta bility to upland regions, of the short-staple or upland cotton, and, on the other hand, the long, fine and strong lint and black seed of the sea island cot ton. The first-generation hybrids were found to be nearly uniform and showed little breaking up of characters of the two parents. In the second gene ration, however, all manners of types were formed, exhibiting the characters of the two parents in very different degrees. Out of several thousand
second-generation hybrids several individuals were selected which showed almost exactly the combi nation of characters which it was desired to pro duce. These hybrids were self-fertilized the next year, and each one was planted in an isolated patch in order that it would be fertilized only with pollen of related progeny. In each generation since, only those plants have been selected for seed which come the nearest to the original type, and now, after five generations of selection, two or three of the types have been bred to a practical state of fixity, showing the pos sibility of combining in a hybrid valuable characters from distinct parents.
(4) Fixation of hybrids.
When different types have been crossed and hybrids secured which possess the char acters desired, it is necessary that careful methods of selection and breeding be fol lowed in order to secure finally a type that will transmit its qualities. The great ma jority of such hybrids when first produced will not reproduce true to type. The policy followed by the writer in the cotton ex periment above referred to, will usually serve as a good guide in the fixation of any hybrid. If self fertile, the hybrids should be fertilized with their own pollen in order not to introduce any new hered itary tendencies unless it is found that such fer tilization too greatly reduces the vigor. In cotton, self-fertilization has been found not to decrease the vigor of the plants, and the same is true of wheat, tobacco, oats, and plants that are normally self fertilized to some extent. In the case of corn, as it has been found that the inbreeding of a plant with its own pollen results in a great deterioration in vigor, it is the best policy to cross the desired hybrid NO another hybrid having the same char acters. The seed of such select hybrid plants should then be planted in isolated places, so that the plants will not be crossed with the pollen of either parent or other varieties. When the progeny of these select hybrids reach a point where their characters be come visible it may be desirable to weed out the undesirable plants that are off type, in order that the plants which most nearly resemble the type desired will be fertilized with pollen from similar plants. In the writer's cotton experiments, the seed of each individual selected plant of the second generation was planted in a small isolated plot of about one acre. As soon as the plants began to show their characters and it could be recognized that certain ones had inherited the desired qualities, the fields were carefully searched and all plants not true to type were pulled up, leaving only a few good plants of the right type. (Fig. SS.) This in sured that all of the later bolls formed would be fertilized with pollen from similar plants of good type. Each subsequent generation, the select plants should be grown in isolated plots and seed selected only from those plants which have reproduced the ideal type for which the breeder is working.