Diseases of Truck Crops and Their Control

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VII POOR SEED It has been briefly stated, page 88, that seeds can be carriers of various diseases. The trucker may also experience difficulty in the germination of seeds which may be accounted for in many ways. Age of Seed. In determining the causes of poor germination the age of the seed is to be...
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VII POOR SEED It has been briefly stated, page 88, that seeds can be carriers of various diseases. The trucker may also experience difficulty in the germination of seeds which may be accounted for in many ways. Age of Seed. In determining the causes of poor germination the age of the seed is to be considered, for after a certain age limit deterioration sets in. With many species of seeds there are apparently no external symptoms to indicate loss of vitality due to age. Each seed has its own age limit, 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. Cultural Conditions. The viability of seed is also largely determined by the conditions under which the previous crop grew. The more vigorous the mother plant the more vitality will there be imparted to its offspring. The vigor of the previous crop depends on favorable climatic conditions, care in cultivation and in fertilization. Old seed produced in a favorable season may be preferred to fresh seed but 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 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 heavy ones sink and the light ones float. Using this method, Stone1 has shown that the heavy sinking seed give a higher per cent. of germination than the lighter (see Tables 10 and 11). T..