258 



GENETICS AND PLANT BREEDING 



The hard and soft wheats provide 

 my last point. Agriculturists, plant 

 breeders, and cxtologists alike will, I 

 feel, ponder long over the rapid con- 

 version of Triticwn durum into T. 

 vulgcire. Lysenko writes; "Michurinists 

 have mastered a good method of con- 

 verting spring into winter wheat." 

 "When experiments were started to 

 convert hard wheat into winter wheat 

 it was found that after two, three, or 

 four ^■ears of autumn planting (re- 

 quired to turn a spring into a winter 

 crop), durum becomes vulgare, that is 

 to say, one species is converted into 

 another. Durum, i.e., a hard 28-chro- 

 mosome wheat, is converted into sev- 

 eral varieties of soft 42-chromosome 

 wheat; nor do we, in this case find any 

 transitional forms between the durum. 

 and vulgare species. The conversion of 

 one species into another takes place by 

 a leap." Biologists are familiar with new 

 species arising more or less by a leap. 

 Primula kewensis being a notable exam- 

 ple, but the conversion of a tetraploid 

 wheat into a hexaploid species is in- 



deed remarkable, and I have no ex- 

 planatory comments. Perhaps, however, 

 I mav be pardoned if this brings to 

 mind some mishaps I have experienced 

 in a long association with seeds and 

 plants. In our pre-soil-stcrili/.ation days, 

 I have seen cldcrbcrn' plants germinate 

 and grow where only goosebcrn,' seeds 

 were sown, also a proportion of red 

 currants Ribes rubrwn among a sow- 

 ing of black currants Ribes nigrum. 



Throughout this small book much 

 space is devoted to various philo- 

 sophical and political themes and ma- 

 terialistic arguments. I have not at- 

 tempted to discuss them; as they have 

 not, or should not have, an\thing to do 

 with biologv. I have, however, taken 

 space in this review to give my experi- 

 ences in the growing, grafting, and 

 breeding of plants and trees to show 

 how they have so often differed from 

 those of the Lysenko-Michurin school. 



I have also given some account of 

 the Soviet "Mentors" and other things, 

 having done this I will leave it to the 

 reader himself to decide what "Men- 

 tors," vegetative hybridization and the 

 like are, and how they work. 



QUESTIONS 



1. Why is it necessary to know some- 

 thing about the hereditary compo- 

 sition of plants used for breeding 

 purposes? 



2. What is meant by vegetative hybridi- 

 zation and what is the author's feeling 

 about it? 



3. What is meant by a "control" and 

 how would it work in a "Mentor" ex- 

 periment? 



4. What opinion does Lysenko have 

 about Lamarckianism and what is the 

 general feeling among biologists re- 

 garding this theory? 



