Alfalfa Seed Chalcid (Bruchophagus roddi Guss.) Infestation Cycles in Relation to Alfalfa Seed Production and Sampling for Resistance in Southern California1
- William F. Lehman2
Infestations of alfalfa seed chalcid were studied on varieties and clones through three seasons in a low desert valley area of Southern California. Chalcid infestations were moderate (35 to 55%) in one test when seed was collected in late April and May, high (59 to 77%) in 1 year and low (16 to 27%) in the other 2 years during June and early July, low (10 to 33%) from the middle of July to the first part of August, and high (60 to 90%) from the middle of August through October in all 3 years. Twenty-two clones were tested for reaction to the chalcid. Four had some tolerance and may be valuable in breeding for resistance. Seeds per raceme varied among clones and through the seed production season. Correlation coefficients between chalcid infestation and seeds per raceme were very low (r = −.16 and +.05) when based on the average reaction among clones but moderate to high (r = + .53 and +.99) when based on the average reaction among dates in the same tests.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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