Breeding Alfalfa for Resistance to the Stem Nematode, Ditylenchus dipsaci1
- R. T. Sherwood,
- J. W. Dudley,
- T. H. Busbice and
- C. H. Hanson2
An experimental synthetic, combining agronomic characteristics of Flemish alfalfa with stem nematode resistance equivalent to that found in ‘Lahontan’, was developed largely by backcrossing. Selections were made in a naturally infested field. Certain selected plants were further evaluated by inoculating their S1 progeny under controlled conditions in a laboratory.
A second resistant synthetic was developed by recurrent selection in the susceptible variety ‘Cherokee’. Laboratory tests of seedling reaction were the basis for all selections; in each of two successive cycles, mass selection was followed by S1 progeny testing of selected plants.
The procedure followed in developing resistance in the second synthetic appeared to be more efficient than the one used in the first. Results from laboratory tests agreed well with those from field tests, but laboratory evaluation was found to be more reliable and economical for determining resistance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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