Three point linkage data for su3 T4-9g wx1

--Stinard, PS

su3 and su4 are a duplicate factor pair that give a sugary kernel phenotype when both factors are homozygous mutant (Stinard, MNL 63–64, 2002). Two point linkage data were reported for su3 and wx1 (T4-9g) in 1992 (6.5 ± 2.6 cM; Stinard, MNL 66:4–5). It is likely that the su3 and wx1 T4-9g stocks used in these crosses carried su4 as well since 1:1 segregation of Su3 and su3 was observed in the modified backcross. Separate lines of su3 Su4 and Su3 su4 have now been isolated, and linkage tests of su3 with wx1 T4-9g have been redone using these new lines. The testcross and results are presented in Table 1. The su3 wx1 linkage distance from these crosses (7.7 ± 2.5 cM) agrees closely with that obtained from the 1992 data (6.5 ± 2.6 cM). These data also provide a test of linkage of wx1 with T4-9g (1.9 ± 1.1 cM), which differs somewhat from that reported by Anderson et al. (4.19 ± 1.55 cM; MNL 39:106–109, 1965).


Table 1. Counts of phenotype segregations for individual ears of self-pollinated plants grown from kernels of the testcross Su3 su4 Wx1 N × [Su3 Su4 wx1 T4-9g × su3 Su4 Wx1 N].

Region 0 Region 1 Region 2 Regions 1 and 2
su N Wx Su T wx su T wx Su N Wx su N wx Su T Wx su T Wx Su N wx
82 62 4 4 0 2 1 0

Map distance su3–T = 5.8 ± 1.9 cM
Map distance T–wx1 = 1.9 ± 1.1 cM
Map distance su3–wx1 = 7.7 ± 2.1 cM