"Darwinian" Selection
See also: Domesticating Wild Plants

Genetic Transilience

Carrière: Domesticating the wild carrot (1865)
In its wild state, the Carrot has a fibrous, tough, much branched root of a whitish colour. Nevertheless, we have procured in a few generations large, fleshy, fibreless roots of a red, white, or yellow colour, some short, some of moderate length, others very long. These varieties are fixed, for the most part, and constitute races that do not vary.

Bürger (Geraniums, 1906)
    During the first years of my experiments, I had scarcely any results worth mentioning. The seedlings always became taller, some of them reached one metre in height before they bloomed, and the results of my labours had for the most part to go to the rubbish heap. My colleagues, when they visited me, laughed at my extraordinary efforts in culture; yet I did not allow myself to be discouraged, but was content with the smallest signs of improvement, in the hope that in succeeding generations better results would be visible.
    Though the results of my efforts were apparently so poor, they were, nevertheless, extremely interesting, and they also kept observation and expectancy at the utmost stretch, although the sacrifices involved were most discouraging.
    I have quietly continued following the prescribed method, and found even in the next generation of seeds a marked advance, which yearly became greater and more astonishing, until ultimately I arrived at the upright form and my seedlings in the autumn are more like young primulas than pelargoniums. The stem has quite disappeared, and only a full luxuriant rosette of leaves clothes the pot, in the middle of which in the spring, often as early as February, the flower-buds appear. This has become the typical form of my strain, of which the principal feature consists in the height of their growth being limited and always restricted to one central truss, which then forms side-shoots out of all the axils of the leaves, which in their turn end in trusses of blooms, so that the plant presents a compact low mass of foliage overshadowed by a splendid bouquet of bloom.

Darwin: Origin of Species (1859)
If selection consisted merely in separating some very distinct variety and breeding from it, the principle would be so obvious as hardly to be worth notice; but its importance consists in the great effect produced by the accumulation in one direction, during successive generations, of differences absolutely inappreciable by an uneducated eye—differences which I for one have vainly attempted to appreciate.

Improving the 'Dancing Plant' Desmodium gyrans (2003)
UDON THANI, Thailand — Dr. Pradit Kampermpool marches through his plant nursery, past row upon row of exotic orchids, before stopping, his chest proudly puffed out, in front of an unremarkable, weedy-looking plant. This plant, he says gravely, cost him a fortune. He developed complicated breeding programs and followed them religiously for almost 10 years to produce it, he says. This plant, he says, is a dancing plant.

Weston: Selective Breeding (1836)
    The following remarks concerning M. Van Mons, are gathered from "Theorie Van Mons, ou Notice Historique sur a moyens qu'emploie M. Van Mons pour obtenir d'excellent fruit de semis; par A. Poiteau" —and from conversations with M. Emilien de Wael, a friend of both named distinguished gentlemen. The "Notice Historique" has been published in translation by the former President of the Society.
     M. Van Mons turned his attention to the discovery of the causes of variation in fruits and flowers. He commenced his experiments at the early age of fifteen years in his father's garden at Brussels, with the seeds of roses and shrubs, and proceeded in the planting of successive generations, with a view to observe the changes and variations. Afterwards, he began with the seeds and stones of fruits. From his repeated sowings of annual flowers and perennial shrubs which bore fruit or perfected their seeds in a short time and by his accurate observations upon the results developed, and by his already extended knowledge of the experience of others he arrived at this conclusion concerning varieties or variation.
    "That so long as plants remain in their natural situations, they do not vary sensibly and their seeds always produce the same—but changing their climate and territory, they more or less vary, and that when they have once departed from their natural state (or commenced varying) they never return to it again, but are removed more and more therefrom by successive generations—and that finally if their varieties are even carried back to the territory of their ancestors, they will neither represent the character of their parents or even return to the species from whence they sprung."
    He also established that so long as plants in a state of nature remain in their native soil they produce seeds which do not degenerate—but that it was different with seeds of a tree in state of change—or as we say improvement, whether the variation be produced by change of climate, territory or other unknown causes, and that the bounds of this change or variation are not known, except that the last seeds from a tree in state of variation will produce a generation nearer a state of nature than those from its first seeds. Hence, the necessity of raising from the first seeds of a new variety if we wish to obtain a tree far removed from a state of nature—as to that state the plant always in age by its seeds, tends, though never able quite to reach it.

Bailey: Improved Pears (1886)
Seeds from young plants appear to produce a better and more variable offspring than those from old plants of the same species. Dr. Van Mons of Belgium, inspired by this fact, built for himself a permanent name in the science of horticulture. He selected seeds from the first fruits of young trees, especially from young trees of new varieties, and planted them. From the first desirable fruits of the seedlings obtained, he again selected seeds and planted, and so continued to do for several generations. Each succeeding generation fruited sooner than the preceding ones and produced better fruit, until about the fifth generation, beyond which there was no increase. The fifth generation of pears bore at three years from the seed. Van Mons proved that by selecting seeds from these young plants, which are in "a state of variation," whose characters are not yet fixed by age, we shall rear the best seedlings.

Cooper: Selection of fruit and vegetables (1799)
In discoursing with a friend, who lived at a great distance from me, on the above subject, he mentioned a fact in favour of changing seed. Some radish seed which he had from me, produced radishes preferable to any thing of the kind ever seen in that neighbourhood, which was near 100 miles distant: but in two or three years the radishes degenerated, so as to be no better than what he had before. I asked his method of saving his seed. He said he had no other radishes in his garden, and when they had pulled what was fit for use, let the others go to seed. I then told him my method, viz: As soon as the radishes are fit for use, I dig up ten or twelve of those which please me best, as to colour, shape, &c. and plant them at least 100 yds. from where any others bloom at the time they do; this, I informed him, was the best method I knew of to improve any kind of vegetables, varying the process agreeably to their nature. I asked him if he thought I should be benefitted by exchanging with him? His answer was, he believed I was the best gardener.

Austin: Horned, Spooned and Flounced Irises (1961)

Carriere: Domesticating the wild radish (1869)

Maurus: Gold Bettas (1981)
The development of the gold strains was an outgrowth of the Cambodian-black cross. A few of the first generation were iridescent green, and a sparkle of gold was noted in the pectorals of some. A second generation (brother-sister) revealed both green and Cambodian fry that grew to possess a golden shininess over their bodies and into the fins. The fins were primarily red, however. Pectoral fins in some were solid gold. Subsequent generations have reduced the red and enhanced the gold. An interesting sidelight is that the fry, when about two weeks to one month old, look very much like little brass nails.

Burbank, White Blackberry (1914)

Burbank, Stoneless Plums (1914)

Burbank: Crested Heuchera (1914)
Several years ago, in examining some of these plants growing wild on a rocky ledge over Mt. St. Helena, I observed one that had leaves slightly crinkled at the edges. This slight, almost insignificant, variation suggested the possibility that farther variation in the same direction might take place if the plants were educated in the right way. So I transferred the plant with crinkled leaves to my home grounds, and in due time gathered its exceedingly diminutive black seeds.
    When the plants were still larger, but before any flowers appeared, about half of the remainder were pulled up; and later in the season still others were discarded that had shown the crinkled condition at an earlier period but did not tend to carry it well as they advanced in age.
    Of the many thousands with which I had started in the spring, only a handful remained toward seed time. And at last a single one among these was chosen as presenting leaves that from the point of view of the experiment were best.

Burbank: Crimson Eschscholzia (1914)
The affinity between the yellow and red, for example, in the case of the poppy, is clearly enough demonstrated in the experiment, outlined in an earlier chapter, in which I developed a race of crimson California poppies (Eschscholzia), the parent species being, as is well-known, bright yellow in color. It will be recalled that the new crimson flower was developed by selection through successive generations from a specimen that showed a little line of crimson, like a streak or thread of another color, lengthwise of a single petal. California poppies of various other colors were developed in the same way, but there were no blue ones among them.

Kunderd: Ruffled Gladiolus (1908)
About a dozen years ago I began selections with a view to crossing in the hope of producing a frilled or ruffled gladiolus as beautifully formed as an azalea. I got the clue from observing in some gladioli a tendency to vary some from the regular smooth petals. After many matings and failures I was at last rewarded about five years ago by the desired results

Castle: Piebald Rats (1914)

Dean: Evolution of "Blotch" and "Belted" in Pansies (1893)

Beaton: Pelargoniums (1861)
It is a curious saying to state that colour can be made to grow, but the fact is certain. A black or brown spot not bigger than a pin's head has been made to grow in Pelargoniums to the size of a broad Windsor Bean; and all the pink, rose, scarlet, and white in that aristocratic race have been grown from small and very insignificant beginnings.

Wilks: Shirley Poppies (1903)
In 1880 I noticed, in a waste corner of my garden abutting on the field, a patch of the common wild field Poppy (Papaver Rhoeas), one solitary flower of which had a very narrow edge of white. This one flower I marked and saved the seed of it alone. Next year, out of perhaps 200 plants, I had four or five on which all the flowers were edged. The best of these were marked and the seed saved, and so for several years, the flowers all the while getting a larger infusion of white to tone down the red until they arrived at quite pale pink, and one plant absolutely pure white. I then set myself to change the black central portions of the flowers from black to yellow or white, and have at last fixed a strain with petals varying in colour from the brightest scarlet to pure white, with all shades of pink between and all varieties of flakes and edged flowers also, but all having yellow or white stamens, anthers, and pollen, and a white base.

Liebman: Pink Guppies (1979)
This entire strain originated from a male guppy named Spot Light. Spot Light had a single highly intense dot on both sides of the caudal peduncle. So highly intense and bright was that single dot, that the fish that sported it caught my eye and was singled out instantly from a tankful of many other guppies. The fish stood out as prominently as a bright light does on a dark night.


Selection for response to temperature

ISHS Acta Horticulturae 766: XXVII International Horticultural Congress - IHC2006: International Symposium on Ornamentals, Now!
Selection for early flowering, temperature and salt tolerance of Zantedeschia aethiopica 'Green Goddess'.
K. Ngamau
Abstract: Zantedeschia, an important cut flower that shows high variability in plant height, flowering period and other characteristics when grown from seeds. Availability of variability, however, provides opportunity for the selection for such characteristics as early flowering, temperature or salt tolerance. In-vitro germination may be utilized in the selection for early germination under unfavourable conditions and selected seedlings rapidly multiplied by multiple shoot formation. This study described the selection procedures using early germinating seeds of Zantedeschia 'Green Goddess' on their flowering time, temperature and salt tolerance. The seeds were sown on in-vitro Murashige and Skoog (MS) medium at 20°C and 16h light; early germinating seeds transferred singly to new medium. For temperature tolerance, seeds were sown on media maintained at 10, 15 and 20°C. For salt tolerance, seeds were sown on medium containing 0, 40, 80, 120, 160 and 200 mmol/L NaCl. The selected seedlings were then multiplied in-vitro to develop clones, which were tested for flowering, temperature tolerance and salt tolerance against clones which germinated later. The results showed that clones, which were selected from early-germinated seedlings, grew faster, flowered earlier and produced more flowers than clones that germinated later. Early germinated seedlings at low temperatures achieved greater growth at lower night temperatures than those germinated at high temperatures. Clones selected after germination at higher levels of sodium chloride (NaCl) attained greater growth on media containing salt than those that germinated on salt free medium.

Jinks & Connolly: Selection for temperature response (1973)
Summary: The extent to which it is possible to predict the performance of selections, made on the basis of their performance in one environment, when grown in other environments and the modifications of the designs of selection programmes that are necessary in order to select for either indifference or sensitivity to environmental variation as well as for mean performance, have been investigated using rate of growth of the dikaryotic stage of the heterothallic, basidiomycete Schizophyllum commune as a model system. The material was the eighth generation of 10 selections. Eight of these, two selected for high and two for low rate of growth from each of two wild isolates, consisted of one high and one low selection from each isolate selected on their performance at 20°C. and the other high and low selection from each isolate on their performance at 30°C. The remaining two selections, one high and one low selection from one of the two isolates, were selected on the basis of their performance at both 20°C. and 30°C. These 10 selections and the two original, unselected wild isolates were compared for their rates of growth over nine temperature environments covering the range 15°C. to 35°C. at 2.5°C. intervals. Lines selected from the same isolate in the same direction but on the basis of their performance at different temperatures, showed significant genotype-environmental interactions with the nine temperature environments. These interactions, which were analysed using both dependent and independent assessments of the environments, could be directly related to the temperatures at which they were selected. In general, selections made at the lower temperature deviated more in the direction of selection at lower temperatures than selections made at the higher temperature, while selections made at the higher temperature deviated more in the direction of selection at higher temperatures than selections made at the lower temperature. Selections made on the basis of their performance in two different temperatures maintained their deviations in the direction of selection over extreme temperature environments much better than selections made at a single temperature. Selections for a low rate of growth at a temperature that leads to a relatively high rate of growth gave lines that were less sensitive to temperature changes than for the same selection made at a temperature that leads to a relatively low rate of growth. The reverse was true of selections for high rate of growth. Selections made on the basis of performance at two different temperatures were always intermediate in their sensitivity to temperature changes. Since all these results are predictable from a simple and general model of gene and environmental action and interactions, they presumably have a general validity.

Risley: Male controls sprouting in roses (1958)


Selection for Earliness

Gardeners Chronicle p 188, September 7, 1901
Journal de la Societe Nationale d'horticulture de France.—The number of the transactions of the National Horticultural Society of France for July, 1901, is interesting as containing several noteworthy papers... M. Denaiffe contributes an elaborate memoir on the cultivated Pea, in which stress is laid on a useful "character." This consists in the determination of the number of sterile nodes on the haulm going from below till the first flowering node (maille) is reached. Thus in the "pois d'Auvergne," the majority of plants produce their first flowers at the twelfth node, while in Prince Albert the majority of flowers are first produced at the seventh node from the base.

Cooper: Selection of fruit and vegetables (1799)
A striking instance of plants being naturalized, happened by Col. Matlack sending some water melon seed from Georgia, which, he informed me by letter, were of superior quality: knowing that seed from vegetables, which had grown in more southern climates, required a longer summer than what grew here, I gave them the most favourable situation, and used glasses to bring them forward, yet very few ripened to perfection; but finding them to be as excellent in quality as described, I saved seed from those first ripe; and by continuing that practice four or five years, they became as early water melons as I ever had.

Irish & Nelson: Identification of multiple stages in the conversion of maize meristems from vegetative to floral development (1991)
Maize plants show a gradient of juvenile to adult nodes, in which characters such as leaf shape, waxy versus hairy leaf epidermis, presence of adventitious roots, and the developmental fate of lateral buds vary from the base to the tip of the plant (Poethig, 1988).

El-Keblawy & Lovett-Doust: New Phytol. (1998) 140:655-665
In control plants [Cucurbita pepo], progeny arising from seeds in the large, fully mature 'early' fruits produced significantly more, and larger leaves by day 30 than did those from late fruits (suggesting differential provisioning in seeds during development). Male flower production had a highly significant positive correlation with vegetative mass and a significant negative correlation with fruit production.

Johnson: Old, Unripe, Dwarfed Seed (1868)
According to Siegert, the sowing of unripe peas tends to produce earlier varieties.

Cooper: Selection for Production Characters in Ryegrass (1960)

Troyer & Brown: Selection for Early Flowering in Corn: Seven Late Synthetics (1976)
Earlier flowering increased yields among late flowering corns and decreased yields among early ones. Earlier flowering increased yields in a short, cool season and decreased yields in a long, warm season. These phenomena can be explained by the contrasting relationships of flowering date with plant size and length of grain filling period: earlier flowering increases yield when longer grain filling period is critical and decreases yield when larger plant size is more important.

Troyer: Selection for Early Flowering in Corn: Three Adapted Synthetics (1990)
Later-flowering synthetics respond more to selection for early flowering than do earlier flowering synthetics. Shorter-season growing areas with longer, cooler days at flowering favor selection for early flowering. The results indicate that selection for early flowering can help export new, diverse germplasm to shorter-season growing areas, to broaden genetic diversity in the shorter-season area.