An unstable gene controlling developmental variegation in okra (Abelmoschus esculentus (L.) Moench)

Summary Genetic studies on radiation-induced chlorina and variegated mutants of okra (Abelmoschus esculentus (L.) Moench) revealed the existence of an unstable gene. The normal green color of the leaves is controlled by duplicate genes C₁ and C₂, either of which produces the green colour. The chlorina plants are C₁C₁C₂C₂. The allele c₁^vis dominant to both C₁ and C₂ but is unstable. The homozygote c₁^vc₁^vc₂c₂ is a normal green while the heterozygote c_i^vc₁c₂c₂ has a variegated phenotype as a result of the mutation of c₁^vto c₁ during development. In green plants with a c₁^vc{sh1/v}c₂c₂ genotype, the autonomous mutation of one of the c₁^valleles to c₁ may take place at the pre-meiotic stage. In the variegated genotype (c₁^vc₁c₂c₂), the mutation of c₁ to c₁^vmay take place in early ontogeny, thus producing green plants. The allele C₁, when associated with c₁^vin a heterozygous condition, mutates to c₁ at the pre-meiotic stage even in the presence of the allele C₂.