A suppressor of floral leaf development

--Steve Briggs

A recessive mutation, designated tassel-sheath (tsh*-50330), has been recovered from Mutator stocks. The mutation causes leaves to develop at the base of each tassel branch. The mutant plants are recognized in the field by an unbranched tassel appearance. The phenotype results from leaves that wrap around the tassel to form a sheath which encloses the basal 1/3 to 2/3 of the tassel. These tassel leaves produce no ligules or blades. Branching of the tassel is normal. Closer inspection reveals that leaves often develop at the base of tassel spikelet pairs on the rachis. These leaves also lack ligules and blades. Homologous structures are produced at the base of each cupule in the ear of mutant plants. Each ear spikelet leaf spans both spikelets in the cupule and is outside (basal to) the glumes. The ear spikelet leaves are not pigmented on P-WR cobs but turn purple on plants that carry B and the associated anthocyanin genes. The ear spikelet leaves become indurate as the ear matures. Maize may prevent the development of leaves in the inflorescence by organ-specific expression of a dominant suppressor of leaf development. The tsh*-50330 allele appears to be a knock-out of such a suppressor.

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