The American Breeders Magazine 3(3): 231-232 (1912)
THE VALUE OF SEEDLING CHARACTERS IN PLANT BREEDING
JOHN BELLING
Gainesville, Florida.

A distinction is made, for the purposes of plant-breeding, between desirable dominant and recessive characters. Once we have a plant with a desirable recessive character or characters, it gives us pure seed for the next season's planting. While if we have a plant with a desirable dominant character, we do not know whether it is pure or not (except in those cases where the homozygote can be distinguished from the heterozygote), and have to sow the seed and wait a year to find out. But if we have studied the seedling characters, and any of them are found to be connate (that is, born together) with the mature character in question, then we can pick the pure dominants from the second or any subsequent generation from a cross with as little loss of growing time as the recessives.

A selected strain of Stizolobiums was found, in the third generation from the cross, to contain a recessive factor which caused the young shoots and pods to be covered with a close black tomentum instead of the usual whitish pubescence. These black plants were all late-flowering. The pure dominant plants were selected without any loss of growing time, and at a minimal expense, by sowing separately in a cold frame, early in the season, fifty seeds from each of the plants with the dominant character. In two weeks it was obvious, from the colors of the plumules, which of the lots of fifty were free from the recessive black. In the same strain there were reasons for thinking that the albino condition (in which purple color is absent from the whole of the plant) was less vigorous than the dominant purple-flowered. (Erwin Baur also found the albino Antirrhinums to die in greater numbers than the colored plants. Compare his admirable genetic monograph in Zeitschrift fur inductive Abstammungs und Vererbungslehre, iii: 70. 1910.) The purple-flowered plants have purple-stemmed seedlings. Thus by sowing fifty seeds each from a number of plants of this strain, we can readily find the plant or plants all of whose seedlings have both purple epicotyls and whitish pubescence on the plumules. These will breed true to both dominant characters, and will have been obtained without loss of time. Such a test can readily be carried out in the winter season, by sowing the seeds in flats.

The larger the mature plants are, the more important is the study of the seedlings, because of the expense of growing to maturity many lines which will have to be rejected. This is especially the case in breeding shrubs and trees. (For instance, one may notice seedling characters in the mango and guava which are possibly connate with definite qualities of the fruit.) I am convinced that in the future it will pay the scientific plant-breeder in some cases to make a microscopical and chemical study of the seedlings, to learn what seedling characters are connate, in the strains with which he is working, with desirable dominant characters of the mature herb, shrub, or tree.