This section is from the book "The Potato: A Compilation of Information from Every Available Source", by Eugene H. Grubb, W. S. Guilford. Also available from Amazon: The Potato: A Compilation Of Information From Every Available Source.
It will be noted that Mr. Paterson in his report to the Highland and Agricultural Society says that, before he got on to the line of experiment which led up to the production of the Victoria, ' potatoes in this country had almost ceased to flower,' let alone bearing 'apples' or 'plums.' Whether that was due to the loss of constitutional vigor, or to the fact that through the process of selection, the varieties which expend all their energies on the production of tubers and not on the production of 'apples' had come to be the only kind generally grown, cannot now be determined. And here we may note a somewhat remarkable fact in this connection. Many years ago Mr. John Wilson, Chapelhill, grew a variety of potatoes which regularly produced a full crop of 'apples.' Mr. Wilson came to the conclusion that the plants could not possibly produce such a heavy crop as ' they could otherwise do if a great part of their energy was expended in the production of ' apples,' and by way of experiment he set his 'hands' to snip the blooms off the plants in a few acres situated in the centre of the field. The result was that the part of the field so treated yielded a crop which was quite two tons per acre heavier than that yielded by the same variety in the other parts of the field which were not so treated. But in the evolution of heavy-cropping varieties ' apple '-bearing varieties are now very few and far between. "In the scientific process of hybridizing, the anthers have first of all to be removed at an early stage of the flowering process in order to prevent the pollen produced on them from lighting on the pistil. Care must also be taken to prevent the pollen of any neighboring plants from lighting on the pistil of the plant to be impregnated. Then the pollen collected from the anthers of the plant to be used as the 'male' in the crossing process has to be dusted on the pistil which is to be impregnated. Care must also be taken that no other pollen is allowed to get near that pistil. Some hybridizers put a glass vase over the cross-fertilized plant, and others follow the plan of tying a muslin bag over the pistil for the same purpose.
One difficulty that often confronts the hybridizer is that the plant he wants to use as a 'male' may not be in bloom at the time that the plant he wants to use as a 'female' is ready for the impregnating process. Another difficulty is that, owing to the 'apple'-bearing capacity having been almost entirely bred out of the heaviest cropping varieties, the plant may not produce any 'apples' though the pistil has been duly impregnated. The taking off of all the blooms but the one to be impregnated has a marked effect in the way of making the plant produce 'apples.' Some hybridizers pick away the growing tubers from the roots for the purpose of causing the plant to expend its energy in the production of 'apples' in place of tubers. With all these devices, however, the hybridizer may pollinate twenty different blooms, and consider himself very lucky if he gets 'apples' on one or two of them. When the 'apples' are full-grown they are gathered and the seed washed out from the surrounding juice, each 'apple' containing from 100 to 300 seed.
The seed are sown in fine rich mould in a greenhouse in the early spring, and after they have sprouted the young plants are planted out in the garden or elsewhere. Each of these transplanted plants will produce a few tubers, mostly all of small size. The first year's seedlings are not invariably of small size, however. Thus at the first show of the National Potato Society at London in 1904 the Sir John Llewellyn Challenge Cup for the best collection of potatoes was awarded to Messrs. Sutton & Sons for a collection of fifty different varieties, which included a selection of seedlings grown direct from the 'apple' seed in the same year, these seedlings being for the most part of quite the size ordinarily obtained from the planting of full-sized 'sets.' Last year also Doctor Wilson, the lecturer on agriculture at St. Andrews University, who has devoted much attention to the scientific hybridizing of farm plants, had an 'apple' seed planted in March which in October showed a yield of six pounds one ounce of fairly full-sized tubers.
The tubers of the seedlings in the first year from 'apple' seed generally show a great variety of type, and even of color, 'blues' and 'reds' being quite common in first year's seedlings, even from seed produced by the cross-fertilizing of two white-skinned and white-fleshed varieties. Then the process of selection begins, and has to be continued for several years until the types selected are properly fixed. A vast amount of patience is required for this work, as very frequently a seedling which gives great promise in its second, third, or even fourth year has eventually to be discarded on account of its failing to come up to the promise of its earlier years.
The Victoria and other new varieties brought out by Mr. William Paterson 'held the field' for a good many years, but in process of time they began to lose their pristine vigor. There were others, however, who took up the work that Mr. Paterson had expended so much zeal upon, and one of the most notable of these workers was Mr. John Nicol, then of the Ochterlony Gardens, Forfarshire, who in the early '70's brought out the Champion, which was a heavy cropper of fair quality and had great disease-resisting power. In the course of a few years this variety was very largely grown in Scotland as well as in Ireland.
Early in the '70's also a number of new varieties were imported from America, and from one of these - the Early Rose - crossed with Paterson's Victoria, there was produced the Magnum Bonum, which was brought out by the Messrs. Sutton in 1876. The Magnum Bonum was a capital cropper, of excellent quality and great capacity for resisting disease. In a short time it took the leading place among all the varieties grown in England.