Genetic mapping of cytological and isozyme markers on chromosomes 1R, 3R, 4R and 6R of rye

Area of Science:

• Plant genetics
• Cytogenetics
• Molecular biology

Background:

• Rye (Secale cereale) possesses a complex genome structure.
• Understanding chromosome organization is crucial for genetic improvement and evolutionary studies.
• Isozyme loci and chromosomal rearrangements serve as valuable genetic markers.

Purpose of the Study:

• To construct detailed cytogenetic maps for rye chromosomes 1R, 3R, 4R, and 6R.
• To physically map isozyme loci and a specific translocation (TR01).
• To investigate the physical extent of evolutionary translocations within the rye genome.

Main Methods:

• Analysis of offspring from multiple heterozygous rye crosses.
• Utilizing cytological markers including C-bands, centromere split, and translocation TR01.
• Electron microscopy of pachytene synaptonemal complexes for breakpoint mapping.
• Linkage analysis to determine gene and marker locations.

Main Results:

• Developed cytogenetic maps for rye chromosomes 1R, 3R, 4R, and 6R.
• Mapped isozyme loci GpiR1, Mdh-R1, Pgd2 (1R), Mdh-R2 (3R), Pgm-R1 (4R), and Aco-R1 (6R).
• Physically mapped the TR01 translocation breakpoint to chromosome arms 4RS and 6RL.

Conclusions:

• Established precise cytological locations for several isozyme loci on specific rye chromosomes.
• Determined the physical extent of evolutionary translocations, particularly involving chromosome arm 6RL.
• Provided a refined cytogenetic framework for further rye genetic research and breeding efforts.