In Chart II we have shown the comparative yields of 30 ears as tested the past season. If we let plot one pick out the four winners we would lose ear 55, the highest yielding ear in plot two. If we let plot two decide the matter we must lose ear 48, the highest yielding ear of plot one. By taking the average yields of both rows we probably get the four best ears, namely 48, 34, 55 and 44. Earlier in my paper I assumed that the proposition that ears of corn vary widely in their productive ability was accepted. The data which I have just given you for another purpose will serve to verify this assumption and also the utility of the ear-row test in finding them. Having found ears of corn which we have reason to believe have hereditary merit, I come to my second question, viz: WHAT METHODS ARE BEST ADAPTED TO THE PERPETUATION OF THEIR SUPERIOR QUALITIES? Two methods of perpetuation are suggested: (1) The selection of seed ears directly from the highest yielding rows in the ear-row test. In this way we shall know with certainty that one parent, the dam, is a superior individual, and if one-half of each row be detasseled and seed saved from the detasseled end, we shall know that it is cross bred, which has been proven to be quite essential; but with what ear it is crossd as sire we shall not know. If nearby rows are from equally high yielding ears, the cross will very likely be satisfactory; but if, as frequently happens, these nearby rows are much inferior to the dam, it would seem that the cross might be impaired. In any event, we know only one parent, either by number or performance record. The progeny of such breeding, I think, might properly be described as half blood. (2) The reserving of a portion of each ear which is planted in the ear-row test and when the harvest has shown which the high yielding ears are, using the remnants of these high yielding ears as the basis for future improvement. These ear remnants may be used in several ways. Some have suggested isolating a single ear, thus building a strain or variety upon the best ear of a given test. We have some evidence along this line which I will give you from the chart in a moment (see inbred ears, Chart IV), which does not look very favorable for the first generation at any rate. Inbreeding of this sort, while likely not as disastrous as self-fertilization, seems to be decidedly ill advised. A much better way is to cross these tested ears in an isolated breeding plot, using one ear as sire and one or more as dams. The four or five best ears of an ear-row test plot may be handled very satisfactorily in a small breeding plot (see Chart III), using one ear-perhaps the best-as sire, planting it upon every other row. Two to four different ears may be used as dams, an ear to a row, detasseling, of course, every row except the sire rows. In this way three or four distinct crosses may be secured, crosses in which both parents are known and their performance records as well. As this system continues, the performance records, not only of sire and dam, but of grandsire and granddam, and on indefinitely, are a matter of record. |