EVALUATION OF SOME CUCURBITACEOUS ROOTSTOCKS 1- FOR RESISTANCE / SUSCEPTIBILITY TO ROOT- KNOT NEMATODE AND FUSARIUM WILT UNDER SCREEN-HOUSE CONDITIONS

Abstract

Southern root-knot nematode, Meloidogyne incognita and Fusarium wilt, Fusarium oxysporum are the most serious soil borne diseases in soil of cucumber. The present study aimed to evaluate some cucurbit rootstocks for their resistance and/or susceptibility to root-knot nematode and fusarium wilt fungus in two successive seasons (2009 and 2010) under screen-house conditions. Data indicated that in autumn season, winter squash ( Cucurbita maxima) was highly resistant and resistant when the pots were inoculated with M. incognita only or nematode plus fungus, respectively. Lagenaria sicenaria rootstock was moderately resistant in both cases of inoculation. Other rootstocks were susceptible to nematode or nematode plus fungus except Luffa aegyptiaca , as it was highly susceptible to nematode. While, in spring season, Benincasa hispida and hybrid 6001 were moderately resistant to infection by the root-knot nematode. Other rootstocks were susceptible to nematode or nematode plus fungus except Cucurbita moschata, Luffa acutangula, and Cucumis sativus var.Hesham, as they were highly susceptible to M. incognita only. Also, Lagenaria siceraria, Luffa acutangula and Cucumis sativus var. Hesham were highly susceptible to nematode and fungus. The results obtained on the enzyme contents showed that some cucurbit rootstocks exhibited the highest contents of polyphenol oxidase, peroxidase and lignin contents being the lowest in some rootstocks. Significant and highly significant reductions in shoot and root fresh weights, root and shoot lengths were recorded in the most cucurbit rootstocks in autumn and spring seasons as a result of nematode , nematode plus fungus or fungus infections compared to non- infected rootstocks.