Ann. Rpt. State Bd of Agric. 15: 206-207 (1876)
Prof. W. J. Beal
Popular opinion in many parts of the country favors a change of seed from one farm or from one county or State to another.
To improve or infuse new vigor into varieties (or races I should more properly call them) I propose in case of corn and some other seeds to get seeds from remote parts where it has been grown for some years, and plant near each other and mix them. Since making the above notes (the idea was original with myself) I have been delighted in reading a review of Darwin's new work on Fertilization of Plants. The reviewer in the Gardener's Chronicle says: "The advantages of cross-fertilization depend on the ancestors of the parent plants having been exposed to different conditions, or from their having been intercrossed with individuals thus exposed. Thus is justified that common practice with horticulturists of obtaining seeds from different localities, and which have grown under different conditions, so that the error and evil consequences of raising plants for a long succession of generations under the same conditions may be avoided. With all species which freely intercross by the aid of insects or of the wind it would bo an incomparably better plan to obtain seeds of the required variety which had been raised for some generations under as different conditions as possible, and sow them in alternate rows with seeds matured in the old garden. The two stocks would then intercross with a thorough blending of their whole organizations, and with no loss of purity to the variety, and this would yield far more favorable results than a mere exchange of seeds." The good results of such crossing will last for several years, though most apparent the first year.
The changing of seed from one kind of soil to another sometimes seems to be of great advantage, but just the rules or laws which govern this change have not been discovered. To some extent it is practicable for every farmer to receive benefit from this at once. Buy seeds of peas, beans, corn, etc., in each case of the same variety, but buy them from different sources, and mix them for sowing for seed.
The yield of seeds by crossing in different ways is shown in the following tables, which will well repay careful study.
|Plants from a cross with fresh stock||Intercrossed plants of the same stock||Self-fertilized plants|
|Mimulus luteus.—The intercrossed plants are derived from a cross between two plants of the 8th self-fertilized generation. The self-fertilized plants belong to the 9th generation.||100||4||3|
|Eschscholtzia Californica.—The intercrossed and self-fertilized plants belong to the 2d generation.||100||45||40|
|Dianthus caryophyllus.—The intercrossed plants are derived from self-fertilized 3d generation, crossed by intercrossed plants of the 3d generation. The self-fertilized plants belong to the 4th generation.||100||45||33|
|Petunia violacea.—The intercrossed and self-fertilized plants belong to the 5th generation.||100||54||46|
In William's Choice Stove and Greenhouse Plants, Vol. I., p. 32, we find the record of some similar experiments made some years ago on several ornamental flowering plants.
|Experiment 1.—Produce of a flower not receiving artificial aid in any way||Experiment 2.—Produce of a flower fertilized with its own pollen||Experiment 3.—Produce of a flower fertilized with pollen from a separate flower grown upon the same plant||Experiment 4.—Produce of a flower fertilized with pollen from a different plant of the same species|
|25 seeds||60 seeds||100 seeds||300 seeds|
Very likely, judging from the first table, the further crossing of different stock of the same variety would have made a still greater improvement in the yield of seed.