Interactions among Loci Conferring Photoperiod Insensitivity for Heading Time in Spring Barley
- L. W. Gallagher ,
- K. M. Soliman and
- H. Vivar
The inheritance of extreme earliness for heading time, as measured by days to awn appearance (DAA), in ‘Super Precoz (2H)’ (SP), a photoperiod-insensitive spring barley (Hordeum vulgare L.), was investigated in field studies under short daylengths at Davis, CA, and Ciudad Obregón, Sonora, Mexico, to obtain additional information on gene action. The DAA data from parental, F1, F2, F3, and F4 generations indicated that extreme earliness in SP was conferred by a single locus when homozygous recessive. Data from 75 F3 families evaluated for DAA in a field study and by starch gel electrophoresis of seedling-plumule extracts indicated that the locus conferring extreme earliness was linked to Est 1 and Est 3 on the long arm of Chromosome 3 with ≈2% recombination. The locus was assigned gene symbol Easp. The dominant allele Easp suppressed the recessive allele easp and permitted the expression of other unidentified Ea loci conferring relative lateness. Allelism tests indicated recessive epistatic interactions between the Easp locus and the Eak and Ea7 loci. The easp recessive homozygote suppressed numerous other Ea maturity loci and headed earlier than the other three recessive homozygotes (i.e., eak, ea7, or eac), which were phenotypically similar.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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