Mottled

A number of aleurone pattern factors (mottled) have been isolated from advanced generations of virus-exposed cultures. When these have been found in differing lines of descent they have been given temporary designations, amt-1, amt-2, etc. The mt designates it as of the mottled phenotype class with the number indicating the sequence of discovery. amt-1 has been redesignated a-ruq, Uq by Peterson and Friedemann (Maydica 28:213, 1983). The remaining cases have been less extensively studied. Although of apparently independent occurrence the possibility of genetic similarity remains.

One approach to resolve this question involves response to a series of colored aleurone testers. Each of the mottled types exhibits mutations to both self-colored and colorless individuals. These can be stabilized upon further inbreeding. The colorless mutants were used in the testcrosses. The dominant mutations have been given temporary designations such as A(m1) CR; m following the A indicating the mutation to self color and the number identifying the mottled stock of origin. If a colored stock carries an appropriate regulator then colored x colorless crosses will exhibit some mottled seeds among the F2 segregants.

A small sample of data from such crosses is presented in the table. All of the crosses have not been obtained but the data available suggest that each "mottled" may have its own specific regulator.

Table. F2 breeding behavior in crosses of amt-types (colorless) with various ACR stocks (r-indicates recovery and nr nonrecovery) of the mottled phenotype among the segregants.

G.F. Sprague


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