South Dakota State University
Allelism of chromosome 2 endosperm mutants -- Whalen, RH Graham, Suresh and Phillips (MNL 67: 102, 1993) mapped the recessive mutation opaque8 (o8) to the vicinity of umc134 on chromosome 2. Since the Maize DB map indicates this is near floury1 (fl1), we crossed the two mutants to test for allelism. Since fl1 shows a dosage effect (i.e., fl/fl/Fl is floury) but o8 does not, the fl1/fl1 plants were used as pollen parents on to +/o8 plants. The resulting ears segregated floury, indicating allelism.

Stierwalt and Crane (MNL 47: 166, 1973) reported a mutation opaque4 (o4) which, unlike fl1, is recessive and does not exhibit dosage effects. As they found it to be allelic to fl1, it is now designated as fl1-o4. Crosses of this mutant with fl1-Ref males gave ears with only floury seeds, confirming Stierwalt and Crane’s findings of allelism. Crosses of +/o8 plants as males onto +/fl1-o4 plants gave ears that segregated for normal and floury kernels, again confirming allelism of o8 and fl1.

Since o8 is allelic to both fl1-Ref and fl1-o4, the o8 mutant should be renamed fl1-o8.

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

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