摘要:

The experiments described in this article show that the greatest seedling injury occurs under conditions that are unfavourable to the host, i.e., high temperature and excessive moisture or low temperature and scant moisture; that the greatest recovery takes place at 15 to 18 °C. in moist soil. They further show that packing and fertilization of the soil increase the amount of infection, though fertilization may increase the dry weight of the seedlings; that the microflora of the soil has little influence upon the seed-borne parasite; that reduction of the oxygen content of a nutrient solution and of soil from 21% to 10% depresses the growth of the seedlings and the amount of infection; that the addition of 1% of carbon dioxide to the atmosphere of soil increases the amount of seedling infection. From these results the conclusion is drawn that barley that is infected withH.sativumshould be sown in cool, moist, well aerated soil.

ISSN:1923-4287    

DOI:10.1139/cjr42c-043

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Experiments with non-sterile soil in large seed beds showed that such soil, if maintained in proper condition, could be used with satisfactory results for tests of seed germinability and of certain kinds of seed-borne diseases in cereals.Non-sterile soil was more easily handled than autoclaved soil and it did not require fresh preparation for each planting.The amount of soil-borne infection in the seedlings was neligible when friable, non-sterile soil was kept moist and at 20 °C.A comparison of the results from 120 different lots of seed showed that a test of seed in non-sterile soil was equal in some respects, and superior in others, to a test on moist paper or to a test on nutrient agar in Petri dishes as a means of measuring seed germinability, seed-borne disease, and physical injury to the seed. With barley seed, a plating test, in addition to the soil test, was found necessary to indicate the amount of seed-borne infection due toHelminthosporium teres.A table of tentative recommendations, based on tests with several thousand seed lots, is given. Seed disinfection is recommended where the smut spore load exceeds 1:128,000 or where seed decay or seedling blight reduces the percentage of healthy seedlings from non-disinfected seed below 91%. Increases in rates of seeding are recommended when the percentage of healthy seedlings, even after seed disinfection, is less than 91% but more than 50%. Seed germinating 50% or less after disinfection is to be discarded.

ISSN:1923-4287    

DOI:10.1139/cjr42c-044

出版商:NRC Research Press    

年代:1942

数据来源: NRC