17 A. H. El- Sappah M. M. Islam. A. Rather J. Li K. Yan Z. Xianming Yan Liang M. Abbas Journal of Animal and Plant Sciences JAPS 20222022/01/07 32 1 99-113 1018-7081 https://doi.org/10.36899/JAPS.2022.1.0407 <p>Root-knot nematode is one of the most serious causes of biotic stress that negatively affect tomato production in China. The robust methodology to overcome this problem is growing resistant cultivars. This study's core purpose is to identify new root-knot nematode (RKN) resistant tomato genotypes out of all 13 available under controlled environmental conditions. After nematode inoculation; morphological, biochemical, and molecular analysis were performed. We observed obvious phenotypic changes in plant height, root length, and root dry weight among all13 genotypes. In comparison with control, nematode infection caused significant halt in plant height in all susceptible genotypes. Three genotypes M3, M7, and M11 were recorded with the lowest values of root gall index and reproduction index. These three genotypes displayed the significantly highest level of resistance compounds; total phenol, ortho-dihydroxy phenol, IAA oxidase, chlorogenic acid, and ascorbic acid contents as compared to the susceptible M82 genotype. Following six molecular markers&nbsp;<em>Mint-1</em>,&nbsp;<em>C&amp;B</em>,&nbsp;<em>TG180</em>,&nbsp;<em>REX-1</em>,&nbsp;<em>JB-1</em>, and&nbsp;<em>Mi23</em>were employed to amplify&nbsp;<em>Mi</em>-genes. Only&nbsp;<em>Mint-1</em>marker successfully amplified a 622bp fragment in M3, M7, and M11genotypes. These findings proved that M3, M7, and M11 harbour root-knot nematode resistance gene&nbsp;<em>Mi 1.1</em>. So, we recommend only M3, M7, and M11 genotypes of tomato for future cultivation to avoid losses caused by RKN infection.</p> Biochemical assay, Meloidogyne incognita, Mi-resistance genes, Molecular marker, Solanum lycopersicum Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=AG-20-0136