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Show AS TO THE SCIENTIFIC BREEDING OF WHEAT Principles Involved Tho Development of Mcndcl'o Laws of Heredity. Much of tho research work now In progress In cereal brcedlnglaconccrned with tho nowly dls-I dls-I ' covered Mondellnn flows of heredity. Tho main principles princi-ples of the methods meth-ods of breeding Introduced ns a sequel se-quel to Mondol's discovery of tho laws of heredity may be demonstrated demon-strated by means of tho whont crosses shown In tho Illustrations. Two very distinct V vnrlotles, ono with I dense ears and a beard, tho othor with lax enrs nnd no jjeaf, woro First Cross. crossed together and gavo the typo shown In tho figure with beardless ears Intermediate In'Bhnpo between' tho lax and dense parents. In this caBo, and In all the others .nvestlgoted, tho direction of tho cross has mado no difference, the hybrids bring Identical whether tho beardless or the bearded variety was the mnl parent For bo sako of simplicity wo will consider first of all tho Inheritance Inher-itance of the shape of tho ear, neglect-.ngfor neglect-.ngfor tho time tho question of whoth-er whoth-er It carries a benrd or not. If tho grain of tho hybrid plant Is sown, It Is found to give rlso to plants with lnx. Intermediate or denso cars, these three types occurring In tho proportion of 1: 2: J. Further, If another generation Is raised, tho lax nnd donso types breed perfectly true to tboso fcaturos, whllo tho Intermediates again produco lax, dense character: There nro only four possible combinations, com-binations, lax and lax, lax and donso, dense nnd lax and denso and donso. Lax meeting dense, or vice versa, we know from tho original cross, gives intermediate, so that this generation will consist of, on on average, ono lax Individual to two with Intermediate ears to ono with denso ears. Further, thn fact that the Individuals inximrccd- feww-tlm-iinlnp of lax-carry-Ing and also from the union ot duiTbu-' carrying reproductive cells, havo not the alternative characters present In their constitutions, they breed true to laxr.css or denseness. The Intorme-dlato Intorme-dlato formed by the union of tho alternative alter-native lax and denso characters cannot can-not bo fixed. Wo recognize, then, that tho intermediate shape Is In this cobo a distinguishing feature of those Individuals Indi-viduals carrying the two alternative characters In their reproductive cells. Tho mero fact that this can bo recognized recog-nized at so early a stago is ono which tho sequel will show to bo Of great value to tho practical breeder. We are now In a position to consider the inheritance of tho bearded and beardless condition, neglecting now the question ot whether Individuals are lax or denBe or Intermediate In car shapg. In tfce first cross tho ears bore no more beard than the beardless parent. The beardless condition Is thus described as "dominant," tho bearded ns "reccsslvo." Tho immediate imme-diate descendants of this hybrid wero cither beardless or bearded Individuals Individ-uals In tho proportion of threo of tho former to one of tho latter. No half-bearded half-bearded Individuals occurred in this or In subsequent generations, Thtf -made., of Intiprltanco of this pair Of features thus "pT!fTTT?HW,l,,"W" ent to that of tho preceding pair, but In reality tho difference Is slight. Ilecnlllng tho fact that the reproductive reproduc-tive cells ot the hybrid carry either tho beardless or bearded character, wo find that the possible combinations of tho pollen grains nnd egg ceils are: (a) beardless and boardless, fb) beardless beard-less and bearded, or (c) vice versa, and (d) bearded and bearded. Tho combination of gametes carrying tho beardless and bearded conditions (b and c) gives (seo first cross) a beardless beard-less plant, so that, on tho average, this generation consists of threo bcardlesv to ono bearded plant. Tho latter (d), tho "recosstves," nil breed true to typo, but two Of tho three boardless types are constitutionally beardless and bearded (b nnd c), and consequently break up In tho following generation, whllo tho third in) formed by tho union of tho beardless reproductive colls only, breeds truo to type. In this wny tho puzzling fact that two Individuals Indi-viduals apparently porfoetly similar to ono another, give when bred from, I - X 1 Parent Varieties, different results, finds a ready explanation. expla-nation. Tho oho is n pure extracted "dominant," tho 'other ft hybrid showing show-ing tho dominant character to tho complete com-plete exclusion of tho nltornntlvo recessive. reces-sive. Thero aru many casos whero oxtcrnnl appearanc"o,ls unfortunately Immediate Descendants of First Cross. Intermediate and denso Individuals In the same proportions. Subsequent generations tell precisely tho samo story, and wo havo to recognlzo tho fact that the lax and denso types produced pro-duced In the first generation raised from tho hybrid plant are. In splto of their parentago, puro with regard to theso features. The explanation of theso phenomena Is based on the fact that tho productive produc-tive cells of tho hybrid, In othor wordB, pollen grams egg culls l!ix dense dws! The Chances of Combination. tho egg cells and pollen grains, carry either tho lax or tho denso character, and not, ns perchanco the outer form of the plant would suggest, a blend of tho. two. (In tho capo of wheat the egg cells ate fertilized with' the plant's own pollen.) Wo enn show tho chances of combination of pollen grain and egg cell dlagramatlcally ns follows, presuming pre-suming that an approximately equal number of each carry either tho lax or no guldo whatever ns to purity of breed, and the Introduction of an apparently ap-parently puro Individual may often bo traced aB tho starting point of a sporting sport-ing or reversion In unlmpeachnblo Hooks and hords. With theso two coses befoio us wo can piece together tho full story of' this particular cross. In the Illustration tho Immediate do- I 1 1 Hybrid Combjning Quality, Yield and Good Straw, scendnnts of tho hybrids nro seen to bo either lax, Intermediate, or dense, with regard to ear shape, nnd each of these types Is represented by beard less or bearded Individuals. Two ol them resemble tho parent vaIetleB, whllo tho remaining four nro distinct Tho question of moment to tho prnctl cal breeder Is whothor theso now Aamjn tm fixed. Those with tho Intermediate In-termediate shape of eiir"miiyT)T5"" Trr once rejected bb hopeless, leaving the beardless donso and tho boarded lax types for further examination. The roccsslve character, I. o., benrdedness, wo havo already seen, breeds truo, lax' ness also breeds true, so that tho com. blnatlon of laxness and benrdedness should bo truo from tho moment of Its appearance. Many experiments have proved this to bo tho caso, |