This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
OBSERVING, in some of the late numbers of your invaluable Horticulturist, that an interest is awakening in the important results from hybridizing' grapes, and also, in an article on the "Delaware" that "the efforts of the hybridizer are yet to be heard from," allow me to send an account of the result of an experiment undertaken six and a half years ago by my brother, Mr. Edward S. Rogers, in our garden of about half an acre or more. He had before experimented on pears, in a small way, according to the directions given for the Cross-breeding of plants in Down-ing's "Fruit-Trees of America," but was stimulated to try this experiment from perusing two articles in the September and October numbers of the Horticulturist for 1847 and 1848 (by the celebrated Dr. Lindley), taken from the London Horticulturist The Isabella (seldom ripening in this northern latitude unless in very favorable situations) and the Diana being only a little earlier, it was desired to obtain grapes combining the hardy and early fruiting qualities of the native with the rich and delicate flavor of the foreign species, which could be grown here in the open air, needing neither aid of glass, sulphuring for mildew, or winter protectionr and unlikely to be cut off by the early frosts of autumn.
For this purpose, a four or five-years' old seedling, growing in the garden, from the New England wild species, Vitis labrusca, was selected as the female parent of the intended hybrids. It is known here as the "Carter," or "Mammoth Globe." Bunches, small, containing from four to eight or nine berries, some of them very large, an inch or more in diameter; in shape, much flattened. Skin, rather thick, Color, brownish red. Ripe about the 1st of September, of agreeable flavor, and superior to most of this species. The Black Hamburgh and White Chasselas, or Sweetwater (Vitis vinifera), had been arranged as the other parent, in a cold grapery near by, to be simultaneously in bloom with the native When the blossoms on the native vine had begun to open, a few clusters were selected, on which to operate, from among those most forward and nearly ready to open. All but five or six flowers were then cut away, and with a pair of scissors, the cap (corolla) of each carefully removed, and stamens all cut off, thus (before their surrounding anthers were quite ready to scatter their own pollen) preparing the pistil for artificial fertilization with the foreign varieties.
This was performed by touching the stigma of each pistil thus exposed, at the moment of taking off the cop or petals with fresh pollen from the anthers on a bunch of the foreign kind, already at band. Each bunch thus operated on, was immediately covered by a smail, fine, cotton bag, to prevent access of the pollen of the vine itself, or any floating in the air, or liable to be carried about by bees, or otherwise. In order to be more sure of the fertilizing action, a foreign bunch, in full bloom, well covered with pollen, was additionally placed therein, and the bag tied up. A day or two afterwards, each bag being taken off, and every stigma again carefully retouched, and a fresh foreign bunch again inclosed with every cluster, all the bags were again tied up, to remain for two or three weeks. When again reopened, grapes about the size of peas, generally, were found, on every cluster, to have set finely, in growing order, and were left to take their natural course upon the vine, each bunch having been previously marked for identity. The bunches, when ripe, were carefully preserved till late in the fall, the seeds of every grape then taken out, and planted in the garden, within a framework under cover of leaves and boards.
They came up regularly, as planted, the next spring, nearly every seed vegetating; but only about one-third (forty-five) of the infant plants could be saved, by daily care, from the ravages of the cut-worm. They were then left to grow, uprightly trained on poles for three or four years; then half the number or more thinned out, and transplanted, being consequently retarded somewhat in their growth and vigor.
In order to ascertain as soon as possible the result upon the fruit, the vines (not knowing whether they would be hardy) were laid down, and covered every winter after bearing. To test their hardihood, precaution being taken to save cuttings, the whole forty-five were then left as growing upon bean poles, totally exposed and unprotected, throughout the winter of 1856-7 - the coldest ever known here, the thermometer, for several successive mornings, ranging from 20° to 25° below zero. The whole untransplanted row (twenty in number) stood untouched and perfectly hardy; about one-half of the twenty-five in the other row stood the same, and the other half lost most of their bearing wood, the surrounding Isabellas and Dianas, of older and stronger growth, suffering likewise; but none two or three feet above the surface of the ground, were at all affected.
As evidence of the hybridization of these vines among them, more or less, is discernible the intermixture or blending of the peculiarity of the foliage and wood of the different species of their parents, some, showing that of the native leaf, round, and slightly serrated, and the woolly under-snrface, and bristly, wiry wood; while others, the greater number, inherit more that of the foreign leaf, with its deep lobes and serratures, and green, smooth under-surface, and large, smooth, short-jointed wood, with prominent, full buds.
In the fruit, also, traces of the intermixture of the two species are obvious in shape, color, size, and flavor, some partaking more of the one, and some the other - those of the Sweetwater variety, however, seeming more uniform than the Black Hamburgh.
The blossoms, too, of these hybrids indicate the different peculiarities of their respective parents, some having the long, perfect filaments belonging to the foreign as, also, to the Isabella, Diana, and Concord varieties (setting their fruit better, and in more abundance from this cause, as far as noticed), and others, the very short filament of this native, which, though blossoming in profusion, with large flower clusters, bears fruit comparatively small in quantity and size of bunches.
The mildew, making its appearance on some of these hybrids (in a mitigated form, however), also significantly points to their foreign intermixture. Its effect, last season (an unfavorable one), was immaterial upon the foliage only; the past season (the most unfavorable one ever known here), the foliage of a few suffered considerably, in common with the Isabella and Diana, and, in a few instances, the fruit of some was attacked slightly. It may be observed that, from want of using any of the precautions mentioned in this process of hybridizing, "people may fancy they have obtained hybrids when they have gained only natural seedlings".
The result of the foregoing experiment - the only one, it is believed, on the native species of New England - would not seem fully to confirm Dr. Lindley's inferences from the experience, on other plants, of the best English authority, the Dean of Manchester, " that, as a general rule, the properties of the male parent will be most conspicuous in the hybrid," but leave an inference that the properties of one parent may be as conspicuous as those of the other, the evidence, however, perhaps slightly preponderating in favor of the rule.