Inheritance of a mutation which suppresses flowering in red clover
1991
Jones, T.W.A.
A spontaneous mutation isolated from stocks of red clover (cultivar S123) prevents flower initiation unless plants are supplied exogenously with gibberellin. Mutant plants are also more upright and densely tillering in their growth habit. Inheritance of the non-flowering character was analysed in a series of crosses between wild-type S123 and mutant plants. Hybridity following intercrossing was confirmed using electrophoretic variants of cytoplasmic phosphoglucose isomerase coded by a- and b-alleles of the nuclear gene Pgi-2. All F1 plants flowered normally and were heterozygous at the Pgi-2 locus. However, F2 segregations did not provide the expected ratios, with flowering plants exceeding predicted levels. One back-cross involving an F1 plant and the mutant parent gave flowering: non flowering and ab:aa Pgi-2 ratios of 2:1 rather than the expected 1:1. The results are consistent with the existence of a zygotic lethal factor, originally present in heterozygous (non-lethal) form in the mutant (nonflowering) parent and tightly linked to the mutated gene. Segregants which were non-flowering always displayed the characteristic mutant growth form and seeds borne on these plants were lighter in colour than those borne on normal plants. Thus, there exists in red clover a gene designated 'dig' (development influencing gibberellin) which has several pleiotropic effects including suppressing the initiation of flowering in normally florally-inductive environments. There are at least two allelic forms of the gene, F (flowering) and f (non-flowering).
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