Genetic mapping and allelisms of Mutator-induced defective kernel mutants - an update

--M. G. James, M. J. Scanlon, P. S. Stinard and D. S. Robertson

A large number of defective kernel mutants (deks) have been generated by crosses to Robertson, DS's Mutator for the purpose of transposon tagging. Previously, we reported on the genetic mapping of 47 Mu-induced dek mutants (MNL 65:11) and the determination of allelisms of 17 of these mutants with each other or with previously described kernel mutants (MNL 65:10). In this report, we describe the establishment of 7 additional allelisms (Table 1), provide more detailed and updated mapping information for four previously described mutants (Table 2), and assign 10 new Mu-induced dek mutants to chromosome arm (Table 3). Chromosomal placements were conducted using B-A translocations, the wx-9 series of reciprocal translocations, and allelism tests, and more definitive mapping was achieved with conventional linkage analyses using genetic markers on the appropriate chromosome.

Table 1. Allelic defective kernel mutants.
 
Mutant designation Allelic to: Chromosome arm Kernel phenotype New designation
dek*-3252 dek*-2058 4S crumpled, discolored, lethal dsc1-3252
dek*-43 et1 3L etched kernel et1-43
dek*-5133 sh4 5L shrunken: collapsed, chalky endosperm sh4-5133
dek*-5132 pro1 8L crumpled, opaque, lethal pro1-5132
dek*-NS413 dek*-NS326 7L reduced endosperm, lethal ren2-413
dek*-PI-AEO dek1 1S floury endosperm, pigments absent, germless dek1-PI-AEO
Dap2 Dap1 5L mosaic aleurone color* Dap1-2
*kernel phenotype listed is for Dap1 Dap1 + and Dap2 Dap2 + heterozygous endosperms, where mutant is carried through the female; Dap1 Dap1 Dap1 or Dap2 Dap2 Dap2 endosperms have mosaic aleurone, reduced endosperm, and are lethal; + + Dap1 or + + Dap2 endosperms are wildtype in appearance (MNL 62:16-17).

Table 2. Genetic mapping of Mu-induced defective kernel mutants.
 
dek mutant designation chromosome linkage testcross % recombination
       
dek25-2410 4S Su1 Gl4/Su1 Gl4 x -su1: 44 +/- 2.39
    (dek25/su1 gl4) -gl4: unlinked
    fl2/fl2 x (fl2/dek25) -fl2: 25 +/- 1.95a
dek7-2608 4S su1 gl4/su1 gl4 x -su1: 8.6 +/- 2.28
    (su1 gl4/dek7) -gl4: 26.7 +/-3.61
    fl2/fl2 x (fl2/dek7) -fl2: 7.1 +/-2.27b
dek31-2689 4L c2/c2 x (c2/dek31) -c2: 18.6 +/-3.91
    gl3/gl3 x (gl3/dek31) -gl3: 19.6 +/- 3.67
    su1 gl4/su1 gl4 x -su1: 32 +/- 4.95
    (su1 gl4/dek31) -gl4: 22.8 +/- 4.17c
emp2 2L wx/wx x (wx T2-9d/dek*-1047) -wx T: 21.5 +/- 2.75
(dek*-1047)   W3/W3 x (w3/dek*-1047) -w3: 18.5 +/- 2.43d
athe data suggest dek25 - 25 - fl2 - 19 - su1

bthe data suggest dek7 - 8.6 - su1 - 18.1 - gl4 and fl2 - 7.1 - dek 7

cthe data suggest su1 - 9 - gl4 - 23 -dek31 - 18.5 - c2

drevised data (from MNL 65:11) suggest emp2 - 18.5 - w3

Table 3. Mu-induced defective kernel mutants placed to chromosome arm.
 
1S 2L 3L 4S
dek*-PI-AEOa dek*-PI-C3a dek*-43 (et1) dek*-3252
  dek*-PI-E3a    
5S 5L 7L  
dek*-NS8070b ren1 (dek*-807)b ren2-413b  
  dek*-PI-OIa    
  Dap2    
amutant was a gift from Steve Briggs, Pioneer Hi-bred Int'l., Inc.

bmutant was a gift from Nancy Shepherd, DuPont de Nemours, Inc.

We also report that the previous placement by B-A translocation of dek*-326 (renamed ren2, MNL, this issue) to the long arm of chromosome 7 was confirmed through RFLP mapping with MAPMAKER by Lance Veldboom, L and Mike Lee, M, Iowa State University. dek*-326 was determined to lie 3.2cM distal to BNL14.07 and 4.9cM proximal to BNL8.39.


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