368 Colchicine 



tetraploid depends upon the physiology of the ixuticuhu' strains. •'• ^•■'• 

 -f"' Advantages such as protein content,^' vitamins,^^ yield of su- 

 crose,3'^ and other valuable characters-'*- -*• ^*' are products of the func- 

 tioning plant. 



A superior baking flour was produced by the tetraploid rye varie- 

 ties. Bread with better texture and color, as well as a larger volume 

 of bread per sample of flour was made from the tetraploid flour. The 

 value for tetraploid was 279 in contrast to the value 260 for a diploid, 

 or an increase of 10 per cent in favor of the tetraploid. Higher pro- 

 tein content was correlated with the improved baking properties and 

 these were in turn correlated with the tetraploid varieties. 



Increased sugar content in triploid watermelon and tetraploid 

 muskmelon improved the eating quality. Increases from 8 to 9 per 

 cent for dijiloids were shown to be raised to 12 per cent in the trip- 

 loid. The (juality and final test of any variety depends upon the 

 genetic nature of the diploid or the hybrid, so that variation exists 

 between tetraploids quite as much as between diploids. The induc- 

 tion of polyploidy does not automatically guarantee improved fruit 

 quality. 



In a j^revious chapter, reference was made to the significant in- 

 crease in amount of sugar produced in the larger sizes of triploid 

 roots compared with the diploid. Tetraploid sugar beets are gen- 

 erally lower in yield of sucrose per unit weight of root. Other plant 

 products, such as latex prodrijced by Taraxacum holisaghyz and trans- 

 lated into rubber production, gave the tetraploids an increase of three 

 times the diploid. Drug production in Datura stramonium showed 

 increased atropin in the tetraploid. Another species, Cannabis sativa. 

 showed increased potency of the marihuana content when additional 

 sets of chromosomes are built into a variety. Environment influences 

 potency of drug production as noted in Chapter 5, but the addition 

 of chromosomes also causes changes in production of special plant 

 products. 



The superiority of tetraploid red clover and alsike clover may be 

 correlated ^vith an increase in forage production. The amount im- 

 proves in the second year over the first. Enough tests have been made 

 with these forage crops, and on a sufficiently large scale, that the 

 conclusion of increased leafage is reliable.^ 



15.5: Microscopic Characteristics 



Pollen size may be used for preliminary sorting of polyploids be- 

 fore the final chromosomal counts arc made for a particular plant. 

 This microscopic classification permits one to handle large numbers 

 of individuals. After the macroscopic identifications are completed, 

 a logical step is to measure the pollen grains. 



