Electrophoretic analysis of Allium alien addition lines.

Area of Science:

• Plant genetics
• Genomics
• Crop improvement

Background:

• Interspecific hybridization is crucial for crop improvement.
• Allium cepa (onion) and Allium fistulosum (scallion) have limited crossability.
• Understanding meiotic pairing in hybrids is key to gene introgression.

Purpose of the Study:

• To investigate meiotic pairing in an interspecific triploid of Allium cepa and Allium fistulosum.
• To assess the potential for gene introgression from A. fistulosum into A. cepa.
• To identify alien addition lines and their genetic markers.

Main Methods:

• Analysis of meiotic pairing in the 'Delta Giant' triploid.
• Backcrossing the triploid with A. cepa cv. 'Temprana'.
• Identification of alien addition lines using enzyme markers (Adh-1, Idh-1, Pgm-1, Pgi-1).

Main Results:

• Preferential pairing of A. cepa genomes observed, with A. fistulosum as univalents.
• Low-level multivalent pairing allowed for interspecific recombination.
• Ten trisomies recovered, representing at least four alien addition lines.
• Pink root resistance identified in diploid, trisomic, and hyperploid progeny.

Conclusions:

• Interspecific triploids facilitate gene introgression from A. fistulosum to A. cepa.
• Successful gene flow achieved at both trisomic and diploid levels.
• This approach overcomes limitations of interspecific diploid crosses for gene transfer.