New ra1 allele --Trimnell, MR, Albertsen, MC In 1997 in our Johnston nursery, we observed ramosa-like tassels in a segregating row of the ms26 male-sterile mutant. The ears of these plants also exhibited a ramosa-like phenotype. We designated this mutant as ra*-ms26. We carried pollen from the ramosa-like plants and crossed them onto A632. These plants were then grown in our Hawaii winter nursery and self-pollinated.

We grew the F2 ears in our 1998 Johnston nursery. Segregation data are shown below (please note that the low plant numbers are due to a mesocyclone that occurred in Johnston during late June):
 
Genotype Wild-type ramosa Corrected X2(3:1)
A632/ra*-ms26 Selfed Ear #1(F2) 5 Plants 2 Plants 0.05
A632/ra*-ms26 Selfed Ear #2(F2) 3 Plants 0 Plants --
A632/ra*-ms26 Selfed Ear #4(F2) 7 Plants 2 Plants 0.04
A632/ra*-ms26 Selfed Ear #5(F2) 5 Plants 4 Plants 0.92

MCA commented during the 1997 nursery that ra*-ms26 looked like a ra1 mutant. Since we did not have any ra1 planted during that nursery, we made the test-cross in our 1998 Johnston nursery using our ra1-DEN allele. Homozygous ra*-ms26 plants were crossed with homozygous ra1-DEN plants. The resultant progenies were grown in Hawaii in our 1998 winter nursery and gave the following results, indicating allelism:
 
Female Male
Progeny
ra*-ms26 Homozygote ra1-DEN Homozygote 0 Wild-type 31 ramosa
ra*-ms26 Homozygote ra1-DEN Homozygote 0 Wild-type 38 ramosa

Our new designation for this ra1 allele is ra1-ms26.
 
 


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