Biotech Updates

Molecular Marker Screening of Tomato Germplasm for Root-knot Nematodes Resistance

March 4, 2011

Tomato (Solanum lycopersicum L.), an economically important vegetable, has been frequently savaged by root-knot nematodes causing production losses in Ghana. The use of effective nematicides have been banned due to their environmental and health risks. Previous studies have shown that the gene Mi found in tomatoes confers genetic resistance to root-knot nematodes. Thus, Y. Danso of Crops Research Institute (CSIR), Kumasi, Ghana and other scientists, conducted molecular screening on some tomato germplasm to detect markers of Mi.

Based on the results, the tomato cultivars VFNT, FLA 505-BL 1172, 2641A, "Adwoa Deede" and Terminator FI showed the marker for the homozygous resistant genotypes (Mi/Mi). The cultivars, Tima and 2644A showed both markers, corresponding to heterozygous resistant genotypes (Mi/mi). Twenty one (21) out of the 26 cultivars did not show any of the markers probably because of non-specificity at the primer-binding sites. Five (5) heterozygous individuals of the 6 resistant cultivars were found to be following the Hardy-Weinberg equlibrium in population genetics.

Read the abstract of this study at