Inheritance of multiple transgenes in wheat

Understanding and predicting transgene linkage relationships is required to utilize efficiently transformation technologies in breeding programs. This study was conducted to determine the co-transformation frequency of three gene sequences by means of a three-plasmid co-transformation system and to determine the mode of inheritance for two genes of interest. Twenty-five independently transformed wheat (Triticum aestivum L.) plants were produced by microprojectile bombardment of 1080 immature embryos with a three-plasmid system. Polymerase chain reaction (PCR) analyses of T-1 progeny from each of the 25 T-0 plants indicated co-transformation of all three plasmids at a frequency of 36%. Two of nine transgenic families containing all three plasmids were characterized for the segregation of the two genes of interest in T-1, T-2, and T-2 testcross generations by PCR. These data suggest that the two genes of interest are linked in both families studied. On the basis of the inheritance of the two genes of interest, one transgenic family would be desirable for use in a breeding program because it contained tightly linked genes, whereas the other family studied would not be desirable for use in a breeding program because the two genes segregated aberrantly.