ACTA AGRICULTURAE SCANDINAVICA SECTION B-SOIL AND PLANT SCIENCE, cilt.63, sa.5, ss.395-402, 2013 (SCI-Expanded)
Tomato (Solanum lycopersicum) is an important horticultural plant in intensive agriculture. Many pests and pathogens affect tomato worldwide. Root-knot nematodes (RKNs) are considered to be one of the most important pathogen groups. Development of resistant tomato varieties to nematode provides an economically and environmentally approach for the management of nematodes. The Mi-1 gene confers resistance to RKNs in tomato. Since resistance testing to RKN is time consuming, laborious, and costly, molecular markers linked to the resistance gene have been developed for breeding purposes. Mi-1 gene is located on short arm of chromosome 6 and very tightly linked to Ty-1 gene. The genomic region containing Mi-1 and Ty-1 is genetically very short. Therefore, there is problem introgressions of plants bearing both Mi-1 and Ty-1. Therefore, some markers such as Rex used for screening of Mi-1 gene can give false-positive results in plants with some of the begomovirus-resistant germplasm derived from Ih902, which has begomovirus-resistance genes introgressed from Solanum habrochaites. Although molecular markers tightly linked to Mi-1 gene have been developed, they have not been applied to a wide range of plants carrying Ty-1 gene or not carrying Ty-1, and compared with each other. In the present study, these markers have been employed in tomato lines and hybrids carrying Ty-1 gene or not carrying Ty-1, and evaluated with each other. A total of 116 tomato plants were tested by markers JB-1, Rex, PMi12, and Mi23. The JB-1 yielded accurate results in all the genotypes tested. Markers Rex, PMi12, and Mi23 gave consistent results in plants that do not have Ty-1 gene. PMi12 and Mi23 also produced logical findings for plants carrying Ty-1. However, marker Rex-1 produced false-positive results in other samples bearing Ty-1 gene, except four plants. Our findings showed that both PMi12 and Mi23 markers can be suggested for screening of RKN resistance in tomato-breeding programs.