relationship between initial population density of meloidogyne javanica and susceptibility of three cucumber cultivars

Root-knot nematodes (meloidogyne spp.) cause approximately 5% yield losses in global crop production and have a wide host range in tropical and subtropical regions. this study investigated the relationship between initial meloidogyne javanica population density and resistance in three cucumber cultivars under greenhouse conditions. seeds of three cucumber cultivars ('super dominus', 'bate-alpha', and 'sina') were sown in plastic pots containing 1 kg steam-sterilized sandy-loam soil and maintained under greenhouse conditions at 27 ± 4 °c. seedlings at the four-leaf stage were inoculated with different inoculum densities of m. javanica (0, 0.5, 1, 2, 3, 4, and 8 eggs/g soil). plant growth and nematode infestation indices were evaluated two months after inoculation. the gall index (gi) and reproduction factor (rf) enabled cultivar resistance evaluation. results showed that m. javanica was pathogenic for all tested cultivars at any initial population density, causing severe (> 50%) growth reductions at higher densities. based on canto-saenz's host suitability criteria (gi > 2 and rf > 1), all cultivars were classified as susceptible.