Genetics of Nematode Resistance in Tomato

Complete dominance of resistance to root knot nematode over susceptibility was noted in a cross involving two parents viz., Tiny Tim and NTDR-1, their F1, F2, BC1 and BC2 generations. The χ2. test indicated that nematode resistance was governed by a single dominant gene. This was further confirmed by the potence ratio (0.991) estimated by six generation means analysis and the absence of non-allelic interactions as indicated by nonsignificant scaling tests. Additive and dominant effects were found to be the major gene effects controlling the expression of this trait.