c-m55437 - an autonomously mutating allele at the C locus

The c-m55437 allele at the C locus has been isolated originally by Peterson (1963). This mutable allele is under the control of the En transposable element system. Test crosses of c-m55437 (c-m Sh Wx/c sh wx X c sh wx1c sh wx) gave rise to an excess of colourless round kernels among the progeny (Table 1). This could be due to the segregation of three or more En elements or the allele is autonomously mutating giving rise to a high frequency of colourless derivatives. In order to differentiate between these two alternatives, plants grown from colourless round sib kernels were crossed to the En tester, c-m(r)/c-m(r), and an En line c sh wx/c sh wx; En. No spotted kernels were found among the progeny of either cross. These results confirm that the c-m55437 allele is autonomously controlled by the En element.

Table 1: Test cross of spotted type. The cross was c-m Sh Wx/c sh wx x c sh wx/c sh wx (shrunken progeny not given).
  Round Progeny    
Pedigree Spotted Colourless Coloured
87K 0331-1 x 0343 53 2 0
-2x0341 160 38 1
-3x0341 160 52 1
87K 0335-1x0341 97 13 2
-3x0341 124 29 11
-4x0342 115 28 6
-5x0341 160 27 7

Ch. Jayaram, P.A. Peterson and A.R. Reddy

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

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