Relationship between ts2 alleles, femaleness and internode length

--Walton C. Galinat

Different ts2 alleles in the presence of the sk (silkless) gene express themselves as different degrees of femaleness in the tassel and this in turn relates to different degrees of internode elongation in the main stalk (Table). The different ts2 alleles originated, apparently, as a result of an Ac factor transposed from the nearby P locus because selection for solid red kernels in variegated stocks led to selection of the different degrees of femaleness in the tassels of ts2 sk combinations.
ts2 allele Est. % Av. hgt, cm Av. internode length, cm
ts2 100 50 4.17
ts2-1 75 60 5.00
ts2-2 50 75 6.17
ts2-3 25 90 7.50
ts2-4 0 l02 8.50

The relationship between the degree of femaleness in the floral phase and the amount of internode elongation in the vegetative phase below is the basis for the complete husk-enclosure of an all female ear. Apparently female development results in the feedback of a hormone-like substance that inhibits internode elongation in vegetative phase below which would otherwise continue simultaneously. The degree of precociousness of female development determines how soon internode elongation will be inhibited and, therefore, how complete the husk confinement of the ear.

A similar relationship may be observed in the tillers of most corn, especially the Northern Flints, in which tillers that are as long as the main stalk duplicate it in having an all male terminal tassel and all female lateral ears. But short tillers have tassels that are partly female and the degree of femaleness regulates the degree of internode elongation.

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors

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