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HORTICULTURE 



May 27, 1911 



MENDEL'S LAW AS RELATED TO 

 HEREDITY AND BREEDING. 



By Dr. Herrmann Decker. Translated from 

 "Cosmos" by Gustave Thommen. 



V. 



When we consider how, in practice, 

 the results obtained by breeding ac- 

 cording to Mendel's law so closely 

 meet its demands, then we may sure- 

 ly predict that this law will be of the 

 utmost importance to the business o£ 

 the breeder and that it will stimulate 

 activity in breeding to a high degree, 

 in the near future. This is the more 

 convincing because breeding, carried 

 on under Mendel's law, becomes a 

 more safe and less costly occupation. 



Biffin, member of Cambridge Uni- 

 versity succeeded in raising new and 

 constant varieties of wheat in a few 

 generations. These new varieties were 

 secured by fallowing up a carefully 

 considered plan, adhering to Mendel's 

 law and combining the best and most 

 useful qualities of several standard 



sorts of commercial wheat. 



Having made sure that such qualities 

 as length of halm, prolificness, size of 

 kernel, immunity against rust, (under 

 same conditions of soil), etc., do obey 

 Mendel's law, convinced Biffin, that 

 new and constant varieties of wheat 

 which would fulfill the expectations of 

 agriculturists could be produced and 

 he obtained them in two or three gen- 

 erations. From this we may gather, 

 what immense treasures the breeder 

 may yet be able to offer to the farmer 

 and husbandman, by closely following 

 Mendel's law. 



A word of warning and advice to 

 those who may undertake breeding in 

 any line according to Mendel's law, 

 will not be in vain. In breeding along 

 the linos of tnis law, the breeder will 

 soon, become aware that many things 

 have to be carefully considered and 

 that plain sailing is not always to be ex- 

 pected. In fact, many times, the breeder 

 may almost lose courage, because 

 something will scim to prove the rules 

 of Mendel's law wrong. These per- 

 plexities have their origin in the selec- 

 tion of the parents. How can the 

 breeder always be sure that these are 

 pure? The longest and most elaborate 

 pedigree is often enough misleading 

 and of no value. 



Our "Blue Andalusian" fowls had so 

 far been regarded as a pure variety 

 (although it. was well known that 

 "breaks" occurred regularly). But the 

 very fact that these "breaks" occur, 

 proves that the blue offspring of the 

 hlack and white parents, consists of 

 bastards only and so can not be con- 

 stant or pure. Then, even if the pa- 

 rents really are pure (in conformity 

 to Mendel's law), there will often be 

 disappointments in regard to the result 

 of some crossings. This will happen 

 when the breeder undertakes to "pair 

 off," characters or qualities which have 

 no relation to each other. 



For instance: If we should choose 

 the red in the petals of one parent and 

 the blue in the other as character 

 marks, we may not kno.v whether the 

 one or the other really is pure; either 

 or both might contain white and be- 

 ing impure in this way, white would 



appear later on in the offspring. And 

 even if both parents really are pure as 

 to each color, tnen the red might be- 

 long to a red sapjuice, while the blue 

 might be a deposit of blue color grains. 

 These would be two characters which 

 could not be combined, because they 

 belong to two dispositions, of which 

 none could suppress the other. Suc- 

 cess in such a case could not be ex- 

 pected. 



It is absolutely necessary that any 

 two chosen qualities shall belong to 

 the same class of characters. Many 

 times close study of the first and sec- 

 ond generation will be needed to get to 

 the bottom of the question and to find 

 the mistake made at the start. After 

 finding and correcting the error, the 

 goal will easily be reached and Men- 

 del's law confirmed. 



What heredity is and how occa- 

 sioned, nobody can say, even today. 

 We only know the laws under which 

 its working can be demonstrated and 

 taken advantage of. Yet, we have a 

 burning desire to unveil this secret of 

 secrets. Mendel has shown us where 

 we must apply the lever if we wish to 

 proceed. He has laid the foundation 

 and many willing hands are now help- 

 ing to further the progress of the 

 building. That so much has been ac- 

 complished already, in this heretofore 

 hopeless territory and that so many 

 gTeat results are sure to be yet ob- 

 tained, only quickens our impulse and 

 hightens our courage. 



Now, what is it that is so new and 

 unprecedented in this theory? That 

 all living things, are successive series 

 of character marks, chains of quali- 

 ties; which at sexual union, are com- 

 pared and are paired off. while one is 

 preferred at the same time. The dis- 

 positions to all these characters and 

 qualities are independent and indivis- 

 ible and are at union easily joined in 

 pairs and in the following generation 

 just as easily seperated. To have 

 given to the world the knowledge of 

 this fact, is Gregory Mendel's great 

 merit. 



But, what are these dispositions? 

 Here we hesitate. Better let us ask 

 first, what are they iiof! Let us re- 

 member, that all theories which reck- 

 on with original dispositions, assume 

 that the small parts of the fertilized 

 egg, by increasing in size and num- 

 bers, become organs and parts of the 

 body. This small part becomes the 

 left eye, that one the right leg, etc. 

 Mendel's dispositions are not of this 

 kind. They are separate, constant 

 powers, which do not enlarge or grow; 

 they remain what they are al.ways and 

 pass from one generation to the other 

 individually and indelibly for all 

 time. The disposition to become this 

 or that, exerts itself as soon as a 

 new being begins its existence. For 

 instance, the disposition to be toothed, 

 in a leaf, begins its work as soon as 

 the leaf begins its growth; it is pres- 

 ent in the plant before the first leaf 

 is even formed; yes, even in the seed. 

 The dispositions controlling height of 

 plant, color of seeds, bearing capacity 

 of parents, sugar contents of fruits, 

 etc. — all these go through the genera- 

 tions and work. The dispositions are 

 capacities or arrangements which set 

 certain transactions in motion. 



In the seed and in the germ they 

 lie dormant and only present them- 

 selves, one after the other, side bv 



side, as their services may be re- 

 quired in the course of the develop- 

 ment of a body. Being transmitted 

 by heredity from generation to gener- 

 ation, all these dispositions meet and 

 working hand in hand, acting one up- 

 on the other, they force the beginning 

 body to form into a harmonious whole, 

 according to a mutual plan. 



This is a subject for thoughtful re- 

 flection and only deep and careful 

 study, combined with well considered 

 experiments (excluding philosophy 

 and preconceived opinions), will bring 

 us further. 



One hundred years ago, Dalton put 

 his "Theory of the Atoms" in place of 

 the vague conceptions entertained as 

 to substance. He claimed, "that sub- 

 stances are built up of separate atoms 

 and that the multiplicity and vari- 

 ability of the chemical substances is 

 the result of the manifold and various 

 ways in which the atoms combine and 

 group themselves." 



Today we meet with the same thing 

 in biology. And just as chemistry has, 

 in the last few decades, advanced to 

 the very foremost position, so do we 

 hope that the new theory, "which re- 

 gards the living being as a mosaic of 

 qualities" will bear fruit and will open 

 for biology (the greatest and most im- 

 portant branch of science), the way 

 to still greater success. 



( THE END.) 



BRITISH BUMPTIOUSNESS. 



Touching the British visitor report: 

 We must commend Mr. Brunton on 

 his able and condensed report. Out 

 of the maelstrom of entertainments 

 he has kept his head very well and 

 given us a very common sense ac- 

 count of their experiences. Of course, 

 it is to be deplored that they should 

 have touched our Boston friends on 

 the raw in connection with their great 

 exhibition. But that was a frank and 

 free expression of opinion and that is 

 what is wanted all the time. Let us 

 not be too sensitive about a little 

 criticism. If it is honest and to the 

 point, it is wholesome; and in that 

 direction lies progress. We will do 

 better next time! And, maybe the 

 Temple Show will do better, next 

 time! You don't suppose these bright 

 boys came to see us without learning 

 something — in spite of their native in- 

 sularity, do you? Of course not. Both 

 countries are benefited. "Sock it" to 

 us! That's what we want! 



G. C. WATSON. 



TACOMA ROSE SHOW. 



E. R. Roberts, former superintend- 

 ent of Tacoma parks, and A. A. Hinz 

 and H. W. Manike. florists, will be the 

 judges of Tacoma's first annual rose 

 show, to be held June 16 and 17 un- 

 der the auspices of the newly or- 

 ganized Tacoma Rose Society. 



The Rose Society has not yet de- 

 cided where the coming show will be 

 held, but expects to lease the first 

 and probably the second floor of the 

 Milbank building on C street for the 

 spectacle. F. C. Smith, another pro- 

 fessional florist, has been named as 

 floor manager and the society dis- 

 cussed preliminary plans for the ex- 

 hibit hall settings. An elaborate floor 

 plan will be designed to the end that 

 the show will be one not only of floral 

 but decorative beauty. 



