Characterization of tomato germplasm for root-knot nematode resistance with the help of mi23 marker

Tomato is a major vegetable crop and a rich source of micronutrients such as vitamins, antioxidants and minerals for a balanced human diet. Biotic stresses, including Root Knot Nematode (RKN) causes significant yield losses in tomato production worldwide. The resistance gene, Mi-1 is currently the only source of root-knot nematode resistance in modern tomato cultivars. In total, 397 tomato genotypes received from ICAR-NBPGR were screened for identifying Mi-1 containing genotypes. A two-step resistance screening protocol involving PCR based molecular screening for Mi gene with gene based SCAR marker Mi23 followed by confirmation of the resistance through challenged nematode inoculation under pot condition was followed. Eight genotypes viz, EC 705452, EC 699717, EC 759288, EC 002644, EC 035420, EC 054644, EC 129606 and EC 050347 have shown positive band to the marker and gave resistance reaction in screening with M. incognita at 2000 second stage infective juveniles per plant under pot condition. The identified resistance genotypes can be used as donors of Mi gene in multiple gene pyramiding and also can be tested as parents in nematode resistance hybrid development programmes.