INTERACTION BETWEEN ROOT-KNOT NEMATODE AND WILT FUNGI ON TOMATO

Abstract

The root-knot nematodes, Meloidogyne incognita (Mi), and wilt-fungus, Fusarium oxysporum f. sp. lycopersici (Fol), devour considerable amount of many agricultural crops including tomato plants Lycopersicon esculentum. Management of these pathogens by cultivating resistant or tolerant plants has an advantage over other measures. It relieves farmers from costly chemical protection and for higher yield and acceptable agronomical extra efforts. Experiments of this investigation aimed mainly to find out tomato cultivars, as major vegetable crop, that possess adequate resistance or tolerance to Meloidogyne incognita (Mi) and/or Fusarium-wilt fungus, Fusarium oxysporum f. sp. lycopersici, infections to avoid crop loss in fields and to disinfect tomato seedlings in nurseries. In this respect, five tomato cultivars namely, Hyb.ypeel 303, H 9035, ALISSA F1, Jakal and Malika, which cultivated by Egyptian growers on a large scale, were chosen for screening varietal test against both pathogens. The obtained results could be reviewed into three groups according to rate of nematode reproduction (Rr) and rate of wilt severity (Rws) parallel with plant growth reaction. First, a resistant plant group comprising Hyb.ypeel 303 and H 9035 cultivars. This was followed by a second tolerant plant group comprising ALISSA F1 cultivar. Lastly, the third susceptible plant group containing the other tomato cultivars (Jakal and Malika cultivars). As with those susceptible tomato cultivars, they were excluded from advanced study because they have no promise for limiting the target pathogens. The selected tomato cultivars (Hyb.ypeel 303, H 9035, ALISSA F1) were evaluated in pot-experiment for rating their levelʼs response against increasing inoculum levels per pathogen. The results revealed that, tom