Establishment of a complete series of a monosomic tomato chromosome addition lines in the cultivated potato using RFLP and GISH analyses

With the aim of establishing a complete monosomic alien tomato chromosome a ddition series in a potato background, the backcross progenies derived from repeated crossing of potato (+) tomato fusion hybrids to potato were scree ned through RFLP and GISH analyses. Because of the availability from our pr evious work of seven of the possible 12 tomato monosomic additions, selecte d from BC2 populations, attention was paid to those alien additions that we re missing. Thus, since the alien additions were already available for toma to chromosomes 1, 2, 4, 6, 8, 10 and 12, efforts were made to select for ch romosomes 3, 5, 7, 9 and 11 by screening specific BC3 populations. In all, 105 plants from four BC3 populations were screened through a combination of RFLP and GISH analyses in order to complete the series. Among the newly se lected alien addition lines, five were monosomic additions for all the rema ining chromosomes and one was a disomic. addition for chromosome 11. When u sing conventional cytogenetics the selection of monosomic alien additions i s highly laborious. All the tomato chromosomes showed a variable rate of tr ansmission. Chromosome 6 was transmitted at 29.6% and 81.5% frequency in po pulations 2705 and 2701 respectively. The present study showed that molecul ar markers and molecular cytogenetics applied in this study were most effic ient and rapid because a pre-selection for the desired genotypes was possib le by screening a population with chromosome-specific markers for the prese nce of one tomato chromosome at a time.