Variation of animals and plants under domestication, v.2

Page 109

200 SELECTION CHAP. XX. young, to the detection of differences in peas in~ended for seed. Mr. Barnet 23 remarks that the old scarlet American straw~erry was cultivated for more than a century without. produc~ng a single variety ; and another writer observes ho~ smg~l~r It was that when g~rdeners first began to attend. to this frmt It be?an to yary; the truth no doubt being that It had always vaned, but that until slio-ht varieties were selected and propagated by seed, no 'conspicu~us result was obtained. The finest shades. of difference in wheat have been discriminated and selected with almost as much care, as we see in Colonel Le Oouteur's works, as in the case of the higher animals ; but with our c~reals the process of selection has seldom or never been long contmued .. It may be worth while to give a few exa~ples of methodical selection with plants; but in fact the great Improvement of all our anciently cultivated plants may be attributed to selection long carried on, in part methodically, and in p.art unconsciously. I have shown in a former chapter how the weight of the goose­berry has been increased by systematic selection and culture. The flowers of the Heartsease have been similarly increased in size and regularity of outline. With the Cineraria, Mr. Glenny 24 "was bold enough, when the :flowers were ragged and starry " and ill defined in cblour, to fix a standard which was then "considered outrageously high and impossible, and which, even " if reached, it was said, we should be no gainers by, as it would " spoil the beauty of the :flowers. He maintained that he was " right; and the event has proved it to be so." The doubling of flowers has several times been effected by careful selection : the Rev. W. Williamson,25 after sowing during several years seed of Anemone coronaria, found a plant with one ~dditional petal ; he sowed the seed of this, and by perseverance in the same course obtained several varieties with six or seven rows of petals. The single Scotch rose was doubled, and yielded eight good varieties in · nine or ten years.26 The Canterbury bell ( Campanula rnediurn) was clou bled by careful selection in four generations.27 In four years Mr. Buckman,28 by culture and 23 'Transact. Hort. Soc.,' vol. vi. p. 152. 24 ' J ourn:tl of Horticul l-ure,· 18G2, p. 3u9. ~5 'Tra.nsact.liort. Soc.; vol.iv. p. 381. 26 ' Transact. Hort. Soc.,' vol. iv. p. 285. 27 Rev. W. Bromuhoad, in 'Gard. Chronicle,' 1857, p. 550. 2s ' Gard. Chrouicle,' 1862, p. 721. CIIAJ>, XX. BY THE ANCIENTS. 201 careful selection, converted parsnips, raised from wild seed, into a new and good variety. By selection during a long course of years, the early maturity of peas has been hastened from ten to twenty-one days.29 A more curious case is offered by the beet­plant, which, since its cultivation in France, has almost exactly doubled its yield of sugar. This has been effected by the most careful selection; the specific gravity of the roots being regu­larly tested, and the best roots saved for the production of seed.80 Selection by Ancient and Semi-civilised People. In attributing so much importance to the selection of animals and plants, it may be objected that methodical selection would not have been carried on during ancient times. ~ distinguished naturalist considers it as absurd to suppose that semi-civilised people should have practised selection of any kind. U ndoubt­edly the principle has been systematically acknowledged and followed to a far greater extent within the last hundred years than at any former period, and a correspondiug result has been gained; but it would be a great error to suppose, as we shall immediately see, that its importance was not recognised and acted on during the most ancient times, and by semi­civilised people. I should premise that many facts now to be given only show that care .was taken in breeding; but when this is the case, selection is almost sure to be practised to a certain extent. We shall hereafter be enabled better to judge how far selection, when only occasionally carried on, by a few of the inhabitants of a country, will slowly produce a great effect. In a well-known passage in the thirtieth chapter of Genesis, rules are given for influencing, as was then thought possible, the colour of sheep ; and speckled and clark breeds are spoken of as being kept separate. By the time of David the :fleece was likened to snow. Youatt/1 who has discussed all the passages in relation to breeding in the Old Testament, concludes that ~9 Dr. Anderson, in 'The Bee,' vol. vi. p. 96 ; 1\lr. Barnes, in 'Gard. Chronicle,' 1844, p. 476. ao Godron, 'De l'Espece,' 1859, tom. ii. p. 69; 'Gard. Chronicle,' 1854, p. 258. 31 On Sheep, p. 18.