Through a combination of pollen viability analysis and genetic mapping, we determined that
at least 12 of the 64 T-DNA lines (19%) that we tested from the Salk collection (Alonso et
al., 2003) display evidence of a chromosomal translocation. We performed pollen viability
assays on all 64 of these lines and comprehensive genetic mapping on 27 of them. For the
genetic mapping experiments we analyzed all 11 of the lines that displayed an abnormal
pollen phenotype, plus an additional 16 lines with normal pollen. We observed that pollen
viability screening was an effective tool for predicting the presence of a translocation in a TDNA
line. All 11 of the T-DNA lines with abnormal pollen had evidence of a translocation
when tested by genetic mapping, compared with only one of the 16 lines with normal pollen.
Because we did not perform genetic mapping on all 64 of the lines in our survey, the fraction of lines carrying translocations may be >19%. Given the low rate with which
translocations were observed in the lines that produce normal pollen, however, it seems
likely that we have detected the majority of the translocations present in these 64 lines.