Swelling Response of Alfalfa Seedlings to Initial Stem-nematode Infection1
- J. H. Elgin,
- D. W. Evans and
- L. R. Faulkner2
We tested seedlings of seven alfalfa (Medicago sativa L.) cultivars inoculated with stem nematodes [Ditylenchus dipsaci (Kűhn) Filipjev] to study relationships between initial nematode infection 3 days after inoculation, 3-day symptoms, 24-day symptoms, and nematode reproduction. Cultivars differed significantly for initial infection, 3 and 24-day symptoms, 24-day nematode populations, and rate of population growth. At 3 days, individual seedling symptoms varied with the initial numbers of nematodes infecting the cotyledonary node. Symptom ratings for individual plants did not change greatly between 3 and 24 days.
Because seedling symptoms at 3 and 24 days depended on the initial numbers of nematodes infecting the cotyledonary node, and because nematode infection is seldom uniform, the breeder may be able to select more effectively if he uses repeated inoculations and waits until differences in nematode reproduction make it possible to distinguish between resistant and susceptible plants.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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