Electrophoretic analysis of Allium alien addition lines.

Meiotic pairing in an interspecific triploid of Allium cepa and A. fistulosum, 'Delta Giant', exhibits preferential pairing between the two A. cepa genomes, leaving the A. fistulosum genome as univalents. Multivalent pairing involving A. fistulosum chromosomes occurs at a low level, allowing for recombination between the genomes. Ten trisomies were recovered from the backcross of 'Delta Giant' x A. cepa cv., 'Temprana', representing a minimum of four of the eight possible alien addition lines. The alien addition lines possessed different A. fistulosum enzyme markers. Those markers, Adh-1, Idh-1 and Pgm-1 reside on different A. fistulosum chromosomes, whereas Pgi-1 and Idh-1 may be linked. Diploid, trisomic and hyperploid progeny were recovered that exhibited putative pink root resistance. The use of interspecific plants as a means to introgress A. fistulosum genes into A. cepa appears to be successful at both the trisomic and the diploid levels. If introgression can be accomplished using an interspecific triploid such as 'Delta Giant' to generate fertile alien addition lines and subsequent fertile diploids, or if introgression can be accomplished directly at the diploid level, this will have accomplished gene flow that has not been possible at the interspecific diploid level.