EVALUATION OF SOME MOLECULAR MARKERS AS SELECTION TOOLS FOR TOMATO MOSAIC VIRUS (TOMV) RESISTANCE IN SOLANUM LYCOPERSICUM L.

D. Kostova, V. RadevaIvanova, D. Ganeva, G. Pasev

Abstract: Tomato mosaic virus (ToMV) is one of the most economically important viruses on tomato (Solanum lycopersicum L.) in Bulgaria, easily transmitted mechanically and by seeds. Breeding, based on genetic controlled resistance, is the most effective and successful approach for combating the ToMV-tomato problem due to the dominant monogenic genetic control, governed by three single genes for resistance (Tm-1, Tm-2 and Tm-22). The aim of the current study was to investigate the reliability of some SCAR, CAPS and AS molecular markers for identification of Tm genes for resistance in tomato breeding lines. Parallel to
molecular study, screening tests with three ToMV pathotypes (0, 1 and 2) were carried out as control tests. The resistance to the three pathotypes was found in 6 breeding lines. Twenty ToMV resistant plants were subjected to molecular analysis. The CAPS marker revealed the presence of Tm-22 allele in homozygous condition in 12 ToMV resistant plants, whereas the AS markers (AS1, AS2 and AS3) confirmed this result only in two plants. The remaining 10 reacted as heterozygous with genotype Tm-2/Tm-22. Another eight ToMV resistant plants were determined by CAPS marker as heterozygous for Tm-22 gene (tm-2/Tm-22), which was confirmed only in two plants by AS markers. The results obtained for the remaining six plants by AS markers were rather contradictory. Successful application of CAPS marker for genotyping the Tm-2 locus as well as confusing behavior of AS 2 marker during genotyping the Maritsa VCRI tomato breeding lines is discussed.

Keywords: allele-specific markers; CAPS; resistance genes; SCAR; tomato; Tomato mosaic virus

Date published: 2017-08-31