CHAPTER III.
ON TRUENESS OF SORT IN ROOT CROPS.
The importance of trueness and purity of seed arises from the evenness of growth of a good genuine strain; while if this quality be wanting we have some parts of our crop growing well, whilst others get on but poorly. Thus a free-growing plant beside one over which it has got the advantage, maintains it for the most part through the whole period of growth. Again, some sorts are of value for being early, others for lateness of growth, and some kinds are better fitted for early than late sowing; if, therefore, we have a mixture in these respects, we may at least expect a partial failure; for whichever is best for our purpose, if mixed will be accompanied by those which are not so good. A want of trueness to sort may arise principally from the following causes:—
1st. Want of selection in seeding bulbs.
2nd. Hybridization.
3rd. A mixture of seeds.
1st. The propriety of selecting the specimens from which seed is to be grown is admitted by all: by the seedsman, who always advertises his turnip and swede seed, for example, as being “from selected bulbs;” and by the farmer, as this announcement is only made to induce him to buy. It is not only important that the roots should be selected, but that they should be stored and then planted in a fresh soil; for as these latter are among the cultivative processes by which sorts have been obtained, so should they be repeated in order to ensure a continuance of the induced condition. Seeding upon the same soil and in the same bed in which the seed is sown is hardly the way to keep up a form induced by cultivation, as this is exactly what would be done by the plants in a state of wildness.
In selecting roots for seeding, care should be taken to choose good-shaped examples, in which a clean unbranched bulb, not too large, with a small tap-root and a small top, confined to a single central bud; a branched root and a many-headed top being true signs of degeneracy. And no less so is neckiness in swedes and mangels, as well as a coarse corrugated skin in roots of all kinds.
Taking such points as these into consideration, how absurd must appear most of the huge mis-shapen roots to which prizes are usually awarded at shows, where the specimens are chosen for size, and trimmed up with the knife, to make them look more presentable. As an evidence of the mistaken principles upon which prizes are awarded to bundles of roots, let any one seed such examples, and we will venture to assert that such seed would produce a large proportion of degenerate examples, without affording so good a crop as would seed, from middle-sized but well-shapen specimens.
2nd. Some of the forms of roots, and more especially those belonging to the Brassicaceæ, such as turnips and swedes, seem to have a wonderful facility for hybridizing; and this not only to the extent of one sort of turnip with another, but sports may be caused by the fertilization of the turnip with rape and its congeners. Indeed, the hybrid with turnip and rape is doubtless the origin of the Swedish turnip; but there is reason to believe that mixtures may accidentally be made with such wild plants as charlocks and mustards, the growth of which in the vicinity of a seeding crop tends to the production of degeneracy. Seeding-patches, then, and the ground about them, cannot be kept too clean.