The genetically unstable dwarf locus in azuki bean (Vigna angularis (Willd.) Ohwi & Ohashi)
Satoshi Aoyama1, Kazumitsu Onishi, Kiyoaki Kato
1Agricultural Research Department, Kamikawa Agricultural Experiment Station, Hokkaido Research Organization, Kamikawa, Hokkaido, Japan.
The Journal of Heredity
|July 5, 2011
Summary
A spontaneous azuki bean dwarf mutant (AD1) exhibits short internodes and dark green leaves. This recessive dwarf trait is genetically unstable, showing bidirectional conversion between dwarf and wild-type phenotypes.
Area of Science:
- Plant genetics
- Molecular biology
- Crop science
Background:
- Azuki bean (Vigna angularis) cultivar 'Erimo-shouzu' yielded a spontaneous dwarf mutant.
- The mutant displays extremely short internodes and dark green leaves.
Purpose of the Study:
- Characterize the inheritance pattern of the spontaneous dwarf mutant.
- Identify the genetic basis and stability of the dwarf phenotype.
Main Methods:
- Cross-pollination experiments with wild-type azuki bean and wild relative Vigna riukiuensis.
- Segregation analysis in F(1), F(2), and F(3) generations.
- Simple Sequence Repeat (SSR) marker analysis (CEDG154) on chromosome 4.
Main Results:
- The dwarf genotype was confirmed as recessive.
- Segregation data revealed dwarf (2.0%) and chimeric dwarf (0.2%) phenotypes in F(2) progeny.
- Chimeric plants showed mixed dwarf and wild-type branches.
- The dwarf trait cosegregated with SSR marker CEDG154, but homozygotes often showed wild-type phenotype.
- The dwarf phenotype is mitotically and meiotically inheritable.
Conclusions:
- The dwarf phenotype is controlled by a single, genetically unstable locus, Azuki Dwarf1 (AD1).
- AD1 locus exhibits bidirectional conversion between dwarf and wild-type states.
- Genetic instability at AD1 influences inheritance and phenotypic expression.
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