6 



BULLETIN 306- U. S. DEPARTMENT OF AGRICULTURE. 



the stage before flowering and the stages when the berries are 

 ripe. In another season, however, the same plants were found to 

 be richer in alkaloids at the second and fourth stages. In the 

 present investigation we find the greatest percentage of alkaloids 

 at a stage of growth which corresponds to the fourth stage in the 

 previous investigation. It seems, then, fur- 

 ther established that the greatest concentra- 

 tion of alkaloids is at the period when the 

 berries are mostly ripe and the leaves small 

 and sparse. 



0.30 

 9 .SO 



% -60 

 v .50 

 * .40 



I 30 



% .20 



fe to 



\ o 



: 





n. 



^^■^^ 



UY- 





V 1 



11 1 1 



II 



II i'l 



-"'""•1 -; ■ 



34 



/3 /2 7W 6W 



COMPARISON OF FIRST- GENERATION PLANTS 

 FROM CROSS-POLLINATED AND CLOSE-POL= 

 LINATED PARENTS. 



Fig. 4. — Diagram showing the 

 average alkaloidal content of 

 all the individual belladonna 

 plants from each parent for 

 the season, second year, 1913. 



From the parent plants, 6w and 7w, which 

 yielded the progeny described in the foregoing 

 pages, seeds were obtained in 1912 through 

 both cross and close pollination and planted for purposes of compari- 

 son. Plants 12, 13, 3, and 34 were dead; therefore no seeds could be 

 secured from them. In their stead, seeds were taken from plants 46 

 and 23, as these were examples of low alkaloid-yielding plants. The 

 seeds were sown in the greenhouse and the seedlings transplanted to 

 the field early in May, 1913. Owing to the hot weather and severe 

 drought the plants made only a fair growth, and only two pickings 

 were secured, the first on August 19, when the plants were in the 

 flowering stage, and the second on September 23, when the berries 

 were in various stages of ripeness. Table IV shows the percentage 

 of alkaloids in the leaves of the individuals from each selected parent. 



Table IV. — Alkaloids in the leaves of first-generation belladonna plants from close polli- 

 nation and cross-pollination of selected parents at two stages of growth at Arlington, 

 Va., during the first season, 1913. 





Alkaloidal content (per cent). 



Lot and number. 



Alkaloidal content (per cent). 



Lot and number. 



First 



stage, 



Aug. 19. 



Second 



stage, 



Sept. 23. 



Average. 



First 



stage, 



Aug. 19. 



Second 



stage, 



Sept. 23. 



Average. 



Lot 6w, close polli- 

 nated: 



1 



0.514 

 .687 

 .421 

 .834 

 .773 

 .731 

 .689 

 .735 

 .696 



0.430 

 .594 

 .504 

 .886 

 .736 

 .724 

 .745 

 .633 

 .669 



0.472 

 .640 

 .463 

 .860 

 .755 

 .728 

 .717 

 .684 

 .683 



Lot 6w, close polli- 

 nated — Contd. 



10 



11 



0.745 



0.658 



0.702 



2 





3 



12 



13 



14... 



15 



16 



17 



18 



.741 

 .687 

 .767 

 .658 

 .703 

 .786 

 .865 



.705 

 .613 

 .750 

 .760 

 .722 

 .741 

 .515 



.723 



4 



.650 



5 



6 



.759 

 .719 



7 



8 



.713 

 .764 



9 



.690 



