Reaction of certain malvaceae cultivars to meloidogyne incognita infection under greenhouse conditions

A greenhouse experiment was conducted to study the reaction of nine malvaceae cultivars i.e. cotton cvs. Giza 86, 70, 90 and 89; okra, cvs Hyper Doki 1& 2 and Ismaily; and rosella, cvs. Hardy and Sabahia 17 to Meloidogyne incognita infection through certain plant growth parameters and nematode criteria. Results indicated that all tested plant growth parameters were obviously reduced by M. incognita infection at various degrees. Of the tested Malvaceae, plant growth parameters such as total plant fresh weights showed the highest reduction percentage values appointed 36.19 and 34.32% by cotton cvs. Giza 90& Giza 86 ; 32.41% for okra cv. Hyper Dokki 1 and 31.54% by rosella cv, Sabahia17, respectively. Meanwhile, their least values of the same criterion assigned 18.70 and 19.81% for cotton cvs, Giza 89 & Giza 70 and 21.81% for okra cv. Ismaily, respectively. Due to the relationship between reduction percentage of plant growth and reproduction factor (RF), Okra cv. Ismaily and rosella cv. Hardy were classified as moderately resistant and intolerant hosts, respectively, whereas cotton cvs. Giza 90 & 86 ; Okra cv. Hyper Dokki 1 and rosella cv. Sabahia 17 were rated as highly susceptible hosts. Meanwhile, cotton cv. Giza 89 & 70 and Okra cv. Hyper Dokki 2 were scored as susceptible hosts to M. incognita infection, since their percentage reduction in total plant fresh weights were amounted to 18.70% & 19.81% and 24.44% and associated with R factor values of 1.6, 1.8, and 1.3 (R1), respectively.