CHAPTER 8 



GERMINATION TROUBLES 



Diseased Seed. Numerous failures in geraiina- 

 tion may be directly attributed to diseased seed. 

 These may cany infection internally in the form 

 of mycelia in the invaded tissue. Seed may also 

 carry infection material externally in the form of 

 spores or sclerotia adhering to the seed coat. 



Age of Seed. In determining the cause of poor 

 germination, the age of the seed is to be considered, 

 for after a certain age limit deterioration sets in. 

 Each kind of seed has its own age limit, which is 

 generally determined by the character of the seed 

 itself, i.e., whether oily or starchy, or lacking in both. 

 Thus the vitality of the minute seed of tobacco is 

 perhaps eight times as great as that of the large oily 

 seed of the castor bean. With many species of seed 

 there are apparently no external symptrans to indi- 

 cate loss of vitality due to age. 



Cultural Conditions. The viability of seed is also 

 largely determined by the conditions undei which 

 the previous crop grew. The more vigorous the 

 mother plant the more vitality will there be impart- 

 ed to its offspring. The vigor of the previous crop 

 depends on favorable climatic conditions, care in 



104 



