INVENTORS OF FLOWERS AND THEIR METHODS

Manawatu Times, Volume 61, Issue 65, 18 March 1936, Page 16

INVENTORS OF FLOWERS AND THEIR METHODS

Human Intelligence Used To Create New Horticultural Species

To Brins Colour And Beauty of Form To Gardens

J7JVEEY AUTUMN flower-show-s in all great cities offer the thousands of visitors the

A normal flower has both male and female elements and propagates by self-pollinations, or is pollinated by insects which carry the pollen from flower to flower. Many a crosspollination is tho result of the whim of a bee or humming-bird. Only human intelligence can create new species, however. The hybridizer chooses a vigorous "mother” plant and a "father” outstanding for tho beauty of shape and colour. He is guided by tho same principles which govern the crossing of a thoroughbred mare and stallion. He will ber-iu by preventing self-pollination in tho female flower, that is by cutting the stameus. This is a long and very delicate operation, especially in the case of composite flowers like the big dahlia, every petal of which is a ligulate flower and the head of a tuft of tubular florets. The second step consists in collecting tho pollen from the male flower aud carefully conveying it to the stigmas of the female, at the moment when they aro ready to receive it. At the present state of knowledge wo cannot say before-hand-what the results of this operation will be, and whether there ivill bo any results at all, because not all varieties of a species lend themselves to such cross-pollinatiou. Every cross-breed-ing is governed by laws which we are just beginning to discover.

The history of the dahlia is a most remarkable example of artificial creation. Y'ears ago it was held that tho dahlia —a native of Mexico —was a hothouse plant. Only the tubular variety was known which, although magnificently coloured, is rather stiff and geometrical. . Then somebody imported a dahlia the petals of which curled in tho opposite direction and were pointed: the cactus dahlia. It at once become tremendously popular and the pompon dahlia seemed forgotten. And again somebody conceived the idea of arranging a marriage between pompon and cactus and thus was born the gorgeous "decorative” dahlia, the pride of growers and the glory of flower shows.

fantastic spectacles of tho autumnal flora, especially dahlias and chrysanthemums, writes Christian de Caters in "Miroir du Monde,” Paris. It is as though in this belated expansion the corolla is more splendid, the petals and shades more subtle and varied, perhaps by reflection of the autumnal golds and rusts.

How many of the thousands who delight in this beauty, give a thought to tho long, patient and ungrateful research work and to the many disappointments and failures which go into the making of a new variety! We must bear in mind that all the beautiful flowers of our gardens are selections and improvements upon nature’s own creations. The origin of some of them goes back thousands of years. Who was the father of the first rose, the Persian horticulturist who made a queen out of a modest dog-rose? Is it chance, is it miracle or is it accident? Most certainly there is a littlo of everything in tho history of flowers. But we are beginning to solve the mystery of tho reproduction of floral species. We are on the road toward the discovery of certain mathematical rules and wo should not wonder if they prove disconcerting to the amateur botanist.

But even the hybridizer is always prepared for surprises because ho operates in the dark,- so to speak. It takes hundreds, perhaps thousands of abortive attempts before a worthwhile new variety can be put on the market. But we may assume that every horticulturist and hybridizer has his own little secrets and fetishes.

But, us stated above, we are on tlie eve of a radical revolution in botany, and wo may envisage a time when the creation of a flower will be an science. Experiments now under way in Russia, America and in other countries prove that the evolution of plants by cross-pollination is- determined by the chromosomes and is governed by a certain mathematical relationship of the male and female germ cells. A too great numerical difference between them might explain the failure of so many attempts. As yet the searchers are groping in the dark but there is no doubt that we are assisting at the birth of a new science. Let us hope for the sake of our gardens that the conclusions drawn from this research may be speedily co-ordinated and made available for practical application. We must always remember that all the beautiful flowers we take delight in are extremely complicated hybrids and for this very reason they carry the germ of degeneration in- them. They tend to lose in beauty, strength and colour. Against this tendency the horticulturist has to wage ceaseless war. In reality every unusually beautiful flower is a monster and nature does not perpetuate itself in monstrosities. As a proof of it wo might quote the double petunia. This is a splendid flower but it has neither pistil nor ovary, because they degenerated into petals. For the propagation of the species it is necessary to despoil a double flower of its petals, preserve it in a pot of moist sand until the dehiscence of the anther and then transfer its pollen or: to a simple flower amputated of its stamens. Throughout the year expert gardeners, botanists, horticulturists, study, and make combinations in order to produce sizes, shapes and. colours that will appeal to the imagination and satisfy fastidious tastes. One-flower plants, clusters of- flowers, scented blooms, every imaginable variety is the result of years of experimenting and of a cautious and delicate’movements of the hand which wields the fino camel’s hair brush with a bit of pollen on its tip. Transferred to a mutilated flower it will become the ancestor of new generations.

The production of new varieties requires a technique of its own. Normally, plants propagate in two ways: either through the germination of seeds or by slips, the latter method being equivalent to the breaking up of the individual. The slip retains the properties >.f its mother plant, yet shows a tendency to degenerate, the intensity of which varies according to the species, nature of the soil and climatic condition. In principle, however, the slip from a plant with red flowers will produce a new plant bearing the same red flowers. But we are beginning to solve the mystery happen feat the shoot differentiates, in which, case we speak of accidental -mutation or : dimorphism. I saw striking examples of in in the tulip fields of Holland, where amongst thousands of tulips of the same colour two or three flowers of an en- • - tirely different colour will grow from ppa bulbs of the same stock. | , The horticulturist who does the i|w|| cutting and layering and severing of gjj§§ tubercle and small bulbs from the Mi® old ones does not play any mechanical j ||| part in this process of propagation. jg|||| Chance and the play of hereditary ||||| reversions will occasionally give him jaßa tlie satisfaction of discovering some new variety. But ho does not act, ifjCjj he merely looks on. I|g|ll This does not apply to the hybrid- |||j| izer, who is out to create novelties and goes about this task armed with botanical and horticultural knowledge, a long experience, the skill of I||||| the surgeons and a mysterious intui- |||pp~ tion. It. is up to him to select the flowers which will be male and female in the artificial fecundation. JHmg| The male element of a flower is hjsfe the stamens, carriers, of the yellow powder known as pollen. In normal pollination the pollen grains fall upon the stigmas when the latter p;l||| are ready to receive them, that . t when they secrete a viscous liquid. gß|| The pollen then travels through the ggH filament to the ovary. At the end of h'fsjjj this evolution is the productions of

A FINE N.Z.-GEOWN DAHLIA "Pink Daily Mail,” a lOfinch diameter bloom, champion at the autumn show of the Karori Horticultural Society.