The host suitability of the ten sugarbeet varieties of monogerm (i.e., Estaban,
Francescan, Sander, Sible and Univers) and multigerm (i.e., Heba, Lilly, Mammut,
Mirados and Oscarpoly) to M. incognita infection was conducted under
greenhouses condition. Results revealed that all yield characters (root, top and
sugar yields) and quality characters, (sucrose, total soluble solids and purity %) of
such screened sugarbeet variety were obviously diminished by M. incognita
infection to great extort. The degree of susceptibility/ resistance of these sugarbeet
varieties evaluated according to modified host parasite index (MHPI) scale which
was used as a new and suitable scale (special technique) to assess host
(sugarbeet plant) reaction. The MHPI is calculated by dividing a gross average of
reduction percentages in all yield and quality characters by the susceptibility rate. It
could be ranked as standardization of host suitability technique and reporting of
resistance of sugarbeet to root- knot nematodes. On this basis, the screened
sugarbeet varieties are categorized into three groups, two varieties are as tolerant
host (Heba and Sible), four as low susceptible (Estaban, Lilly, Mirador and Sandor)
and four as moderately susceptible (Francescan, Mammut, Oscarpoly and Univers)
against root- knot nematode, M. incognita. So, they could be Heba (as multigerm)
and Sible (as monogerm) varieties recommended as excellent commercial varieties
in Egypt, and could be introduced in integrated pest management (IPM) for
controlling root-knot nematodes.