Aneuploid and other cytological tester sets in rye

Abstract

Cytological tester sets include series of aneuploids (nullisomics, monosomics, trisomics of different types, tetrasomics), series of rearranged chromosomes (translocations, inversions, duplications, deficiencies) and series of chromosomes recognizable by specific microscopically visible markers (C- or other banding, molecular markers). In rye, only a few (mainly tertiary and telocentric) monosomics and no viable nullisomics have been found. Several sets of primary trisomics and some telocentric sets, usually not fully complete, have been developed, but few are still available for gene localization. A few tertiary trisomics have been derived from translocation heterozygotes. Extensively used are different sets of additions of rye chromosomes to wheat. A relatively widely distributed set of marked chromosomes is the Wageningen translocation tester set, complemented with translocations from different other institutions. A disadvantage of rye translocations is insufficient heterozygote semisterility. Series of otherwise rearranged chromosomes have not been reported. Sets of lines with chromosomes conspicuously differing from the standard C-banding pattern have been obtained. Molecular markers are available for most rye chromosome, but lack of heterozygosity, necessary for classification after in situ hybridization is a restriction for use as cytological testers. In the cases of most translocations, C-banding and in situ molecular markers, each separate plant in a segregating population must be screened cytologically, whereas with aneuploid markers or with translocations having sufficient heterozygote semisterility, analyzing segregations is sufficient.