Germination Troubles 105 



cultivation, and in fertilization. Old seed produced 

 in a favorable season may be preferred to fresh seed 

 of an inferior quality produced in a bad season. 



Weight and Color of Seed. As a rule, light weight 

 seed is inferior to heavy seed of the same variety. 

 The weight of the seed is influenced by culture, and 

 by imperfect fertilization which results in minute 

 and weak embryos. The comparative weight of seed 

 may be readily determined by the water method. 

 Place the seed in a tumbler filled with water. After 

 shaking and letting it stand for a few minutes, the 

 heavier seed sink and the lighter float. Using 

 this method, Stone has shown that the heavier* 

 sinking seed give a higher percentage of germina- 

 tion than the lighter. (See Table 15.) 



Table 15 



Name of Seed} 



No. of Seed 

 : Germinated 



Per Cent, of 

 Increase in 

 Germination 



Light 



Heavy 



of Heavy Over 

 Light Seed 





68 



90 



32 





100 



117 



17 





38 



85 



142 





44 



88 



100 





50 



58 



17 





60 



87 



61 



The color of the seed does not seem to have any 

 influence on the germination. Darker colored seed 

 is usually preferred to the lighter of the same va- 

 riety. Color, however, largely depends on the de- 

 gree of ripeness. 



♦Stone, G. E., Massachusetts Agr. Expt. Sta., Bui. 121 : 3-14, 1908. 



