Sources of tolerance to root-knot nematode, Meloidogyne javanica, in cultivated and wild tomato species

Abstract

Five elite tomato cultivars (HT-5044, HTA-18, HTA 19, HTA-31 and HT-Ravid 244), two locally gown Nigerian cultivars (Roma VF and Nsukka local) and a wild tomato related species (Lycopersicon pimpinellifolium) were assayed for their responses to an indigenous population of M. javanica in the greenhouse. Infected plants were scored for galling on a 0-5 rating scale. The cultivars HTA-18 and HTA-31 had significantly (p<0.05) fewer gall counts per root system and per gram fresh weight of root than the other cultivars. Single degree of freedom analysis showed that HTA-18, HTA-19 and HTA-31 had significantly (p<0.05) fewer galls than the locally grown cultivars. HTA-18 and HTA-31 were moderately susceptible with Gall Index (GI) of 3, while the rest of the cultivars were highly susceptible (GI>4). The nematode caused a significant delay in flowering and a decrease in fresh and dry weights of roots, stems and leaves in the cultivars, HT-5044, Roma VF and Nsukka local. HTA-18, HT-Ravid 244 and the wild species were considered tolerant. © 2008 Asian Network for Scientific Information.