The Amphiploids 301 



gation of the Fj plant was devised so that several hundred plants 

 coidd be obtained in one season. These were treated by soaking the 

 roots in colchicine. ^^^ Fertile spikes indicated .56-chromosome plants. 

 The work was progressing satisfactorily until in 1944 the research 

 jjlot became the scene for \V'orld War II. Because of considerable loss 

 of material and change in personnel, the original plan had to be 

 modified radically. 



It is encouraging from the viewpoint of polyploidy that Triticales 

 are now regarded as potential breeding material instead of a genetical 

 curiosity, as it was for a good many years. 



12.2-^: Artificial and natural polyploids in Graniineae. Large- 

 scale synthesis of polyploids by colchicine can be of use theoretically 

 and practically.^**^ Newly created polyploids in grasses were placed for 

 testing on range, pasture, and luitended habitats. Following such an 

 introduction, continuing records will show up the potentialities for 

 adajjtation of the new species, for the competitive success or failiu'e 

 would become evident after several generations. To a degree, princi- 

 ples governing success apply to polyploidy among intensively culti- 

 vated situations, as well as in pastures or wild habitats. ^^'-^ 



Among Triticales we mentioned the maintenance of constant 56- 

 chromosomal plants after fifty generations of cidture. Backcrosses to 

 wheat always favored the more vigorous 56-chromosomal plants. Ap- 

 paiently a stabilizing mechanism operates in the Triticales complex. 

 Undoubtedly this is true for many polyploids among grasses where 

 70 per cent of the species are natural polyploids. Therefore, new 

 polyploids with high numbers and complex genomic additions shoidd 

 bring important facts to our attention. -^ 



Such projects involving artificial and natiual polyploids carried 

 out by Stebbins and his associates have already added important in- 

 formation, i*''^- ■'- Further research based on long-range objectives will 

 surely advance our knowledge of polyploidy. 



In the valleys and foothill regions of California, agricultural prac- 

 tices have created three ecological situations into which natural and 

 artificial polyploids shoidd show differences in adaptation. First, the 

 once native grasslands that have been there are heavily grazed and 

 are now covered with annual species from Europe. Second, luigrazed 

 fields nearby are filled with introduced species. Third, there are 

 pastmes suitable for reseeding forage crops or grasses and for con- 

 trolled grazing. Obviously this is a tuiique situation representing 

 three unstable plant associations. Into these habitats artificial as well 

 as natural polyploids can be introduced by seed and/or vegetative 

 starts.i"^ 



Large ])opidations of artificial polyploids, both autoploid and 

 amjjhiploid, were made by colchicine methods. ^'^'•'' One successfid 

 autoploid, Ehrharta erecta, will be discussed in the next chapter. Here 



