Tests for increased mutation rate in mutable controlling element stocks

A survey of seedling mutants isolated from the mutator line (Mu) indicates that 15% are mutable. Because mutability is a characteristic of mutants influenced by controlling elements, the relationship between Mu and other mutable systems such as Dt, En and Mp is of interest. This relationship can be tested in two ways: 1) by determining if controlled alleles of the above systems respond to Mu and 2) by using mutable controlling element stocks in a manner analogous to the Mu line to test for an increase in the mutation rate. Preliminary results of the latter test are presented here.

Plants were self-pollinated and crossed to a standard line, and a sample of the outcrossed seeds were self-pollinated. The following results were obtained:
Stock Number of outcrosses tested Total number of plants Number of mutants % mutations
Dt 8 342 0 0
En 8 343 0 0
MP 8 318 0 0
Total 24 1003 0 0

It is clear that there is no dramatic increase in mutation rate in these stocks.

Peter Mascia and D. S. Robertson

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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