GROWTH CONTROLLED BY SIZE 

 OF POT 



Figure 16. Two plants of the variety 

 Kymington grown under identical conditions 

 except that one was in a four-gallon, the other 

 in an eight-gallon pot. Although the rate of 

 growth is directly dependent on the size of the 

 pot, the time required for the plants to flower is 

 practically the same in all cases. 



BRANCH OF A FEMALE PLANT 



Figure 17. The genus. Cannabis, to which 

 hemp belongs consists of a single species. It 

 belongs to the Mulberry family and hops is 

 the nearest related genus. This is a disadvan- 

 tage, genetically, as it is desirable to have two 

 rather closely related species, having the same 

 chromosome number. 



the distribution of characters in the 

 chromosome groups. The chromosome 

 number in Cannabis is somewhat larger 

 than in Drosophila melanogaster and 

 Crepis virens but it has the same num- 

 ber as Zea maize (corn). A low chro- 

 mosome number facilitates the isola- 

 tion of linkage groups but a high 

 chromosome number does not prevent 

 the discovery of linkage relationships. 

 Wood worth ^ has isolated four linkage 

 groups in Soja max which has about 

 20 haploid chromosomes, and at least 

 6 linkage groups have been found 

 in corn. It would appear, then, that 

 it is possible to analyze and locate 



groups of factors corresponding to 

 the different chromosomes where the 

 haploid number is as high as ten. 



Hemp is a dioecious plant reaching a 

 height of eight to twelve feet under 

 favorable environmental conditions. 

 Their development under green- 

 house conditions at Urbana, Illinois, 

 was found to be definitely controlled 

 by the size of the pots in which they 

 were grown. Those in 8-gallon pots 

 were from eight to ten feet in height, 

 and averaged two to three feet taller 

 than the plants grown in pots half that 

 size. The taller plants were more 

 robust than the smaller ones but all 



■ WoouwoKTH, C. M. Inheritance Studies in Soybeans. I. Cotyledon, Seed-coat; Hilum, 

 and Pubescence colors. Genetics, VI. 



