W. V. SWINCI.K. — VAIil\TIU.\ IN Fll;sr (,KM';i;ATI()\ IMIllilDS. r.S7 



liii()iit;li liMs liccn s;ii(l \n show lli;il I licrc .-ii'c si rikiiijj- vju'iations nnioiiii' 

 lirsl-genci'iilioii livl_)ri(ls ol'cili-ous l'niils. 



Messrs. C.ollins aiul Kcniploii', iii .•m .■iiliclc |)i'csi'mI('(I lo lliis uoiii^rcss, 

 liavr- oivoii coiicliisixc cvidcnrc ol' llir vai'\iiit; lii'r<'(lilni'v naliire of dilTcrcnl 

 iiidivicliial plaiils ol' liisl ^ciicialidii plaiils uï iiiai/e, alLhoiit>li Iheso dill'eroncps 

 were indicalcd l)y Ihc naliii'cor llic l'ii(1os|I(_'imi ilsclf r('pi'('S('nlin<;^ F,, or llie 

 porjiigale gciirralioii. A Cliincse niaizewilli 

 a waxy enduspcriii was cio'-sed \\ illi Mexican 

 maize willi a horny eiidosporiii ol' llic iisiial 

 lypc. Tlio lioiMiv oiidospei'in \va>- doiuiiianl. 

 so ail Ihc ki'i'iicls on Ihc crosscd <'ars showcd 

 lh(? horiiy characlcr. 'l'hcsc I<onicls sowcd 

 soparatcly gave risc lo plaids ol' Ihc lii-^l 

 gcncralion (F,! wliirii wcrc scll'-p<dlinalcd. 

 The resulliiig cars showcil \aiying percenla- 

 ges ûf kernels wilh a waxy cn<h>sperm from 

 ir».7lo ,10.0, approacliing nearlybiit notcpiile 



10 Ihe expeeled Mendclian ratio I-." (being -',". I 

 iiisicad ofl'.'p pcr IIIDl. 



In as iinirh as Ihc cars (■()nlaine<l a large 

 iiiiiidier ol kci'iiids Ihcrc can lie no doubl bul, 

 Ihal llicir varying p<'i(enlagcs represenled 

 real dill'erences in Ihc Jiereditarycomposilion 

 of Ihe firsl génération plants. Il would be 

 liaL'd lo lind a niorc concliisi\(> casi> since 

 Ihcrc could bc no donbl as lo Ihc pnrily of 

 Ihe parcids and w liai is more rare no possible 

 donbl as lo whether a giv(Mi kernel had a 

 waxy or a horny endosperm. 



Such variations among individuals ol' 

 lirsl generalion hybrids aie noi iiiiknown lo 

 sludenls of genetics and llicsc phenomena 

 hâve been relcrrcd lo varialjle domiiiancc liy 

 Uiose who lise Ihc AbMidelian lerniinology. 



11 has nol, howi'xcr. been r('ali/iMl liow Calai 

 Uiis phenoiiiciioii is lo some ol' Ihc (diicf Ic- 

 nels ofmodern théories ol'heredily. Already 

 in 1897 al Ihe Ilhaea meeting ol' Ihe American 

 Assoeialion for Ihc Advancemenl of Science, 

 I called allciilioii lo Ibis phenomenonand, lo 

 aecoiinl l'or il. pioposed a provisional bypo- 



lliesis of whicli a siiinmary was given in llie l'oUowing words : 



'"Il was poinUnl oui lliat Weismann's Iheory of rediiclion of chromosomes, 

 Ihough giving a |ilausible explanalion of Ihe dill'erences observed belween Ihe 

 firsl (uniform) and se<'ond (polymorphie) générations of mosl hybrids, is nol 



only in disaccord willi 11 bscivcd phenomena of spore and pollen formation 



in higher plants, biil l'ails lo acconnt l'or Ihe extrême polymorphism often 



l. Ccillili 

 Cdi-n. iii llici 



.1, Il . l'.ll-J. Ilillriila 



Il llvlindf "l'Clii 



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