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  • Author: Monika Godzina x
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Varying abundance and dispersal of the two-spotted spider mite (Tetranychus urticae Koch, 1836, Acari: Prostigmata: Tetranychidae) on Mi-tomato plants differing in allelic combination

Varying abundance and dispersal of the two-spotted spider mite (Tetranychus urticae Koch, 1836, Acari: Prostigmata: Tetranychidae) on Mi-tomato plants differing in allelic combination

It is well known that the presence of the Mi-1.2 gene determines the resistance of tomato plants (Solanum lycopersicum L.) to 3 root-knot nematode species and some insect herbivores of the order Hemiptera. In this study, the density and dispersal of two-spotted spider mites (Tetranychus urticae) on tomato plants of 4 cultivars were evaluated under greenhouse conditions, to find out whether tomatoes differing in allelic combination of the Mi-1.2 gene exhibit similar or different resistance to the mite pest. The results show, for the first time, that the same initial number of mites develops into populations that vary in abundance and distribution depending on tomato allelic composition of the Mi-1.2 gene. The results indicate that the mite-pest develops more slowly on tomato plants of cultivar ‘Motelle’, carrying 2 dominant alleles for the Mi-1.2 gene, than on heterozygous ‘Altess F1’ tomatoes and both cultivars carrying only recessive alleles of this gene: ‘Moneymaker’ and ‘Plaisence F1’. This suggests that the Mi-1.2 gene may be involved in tomato resistance against spider mites when this dominant gene is expressed homozygously, but this needs to be verified by further research.

Open access
Relevance of the Mi23 Marker and the Potato Aphid Biology as Indicators of Tomato Plant (Solanum lycopersicum L.) Resistance to Some Pests

Relevance of the Mi23 Marker and the Potato Aphid Biology as Indicators of Tomato Plant (Solanum lycopersicum L.) Resistance to Some Pests

Mi-1.2 gene, expressed in tomato plants, contributes to endogenous resistance against nematodes and some Hemiptera insects. The aim of this study was to screen the presence of dominant/recessive locus of the Mi-1.2 gene in tomato cultivars with different allelic combination using Mi23 SCAR method and to assess the capacity of the local potato aphid (Macrosiphum euphorbiae Thomas) population to develop on different tomato cultivars (dominant and recessive homozygotes in Mi-1.2 locus). The results showed that both Mi23 marker and potato aphid performance are relevant methods in screening tomato cultivars with a different allelic combination of Mi-1.2 gene. The assessment of biological potential of M. euphorbiae proved that, in comparison with control (tomato plants with recessive alleles of Mi-1.2 gene), the aphid mortality increased 9- and 4 - fold (in the first and second experimental series, respectively) and the female longevity decreased 3 - fold when fed on tomato cvs with dominant alleles of Mi-1.2 gene. Furthermore, the resistance against aphids manifests as an antibiosis mechanism in tomato plants carrying dominant alleles.

Open access
Tomato Carrying MI-1.2 Gene as a Host-Plant to the Two-Spotted Spider Mite (Tetranychus urticae Koch): Results of Laboratory Evaluation

Tomato Carrying MI-1.2 Gene as a Host-Plant to the Two-Spotted Spider Mite (Tetranychus urticae Koch): Results of Laboratory Evaluation

Mi-1.2 gene contributes to the resistance of tomato plants against some species of herbivores (i.e. nematodes, aphids) that are sap-feeders. In this study, two genotypes of tomato (Solanum lycopersicum L. syn. Lycopersicon esculentum Mill.) plants with dominant (Motelle cv) and recessive (Moneymaker cv) Mi-1.2 alleles were evaluated as a host-plant to the two-spotted spider mite (Tetranychus urticae Koch, Acari: Tetranychidae). Plants were grown under glasshouse conditions. The effect of tomato genotypes on T. urticae bionomy was estimated on cut leaflets in controlled photoperiod, temperature and humidity (L/D=16/8 h; D/N temp.=23/20°C; RH=70%). Results of laboratory evaluation showed that both the bionomy and population parameters of T. urticae reached a very similar or even higher value on plants with dominant Mi-1.2 allele than on plants with recessive one. A relatively high value of T. urticae parameters on plants resistant to root knot nematodes indicates that the mite has potential to develop rapidly. This allows the mite population to reach the density causing marked damage to plant in a short time. It is concluded that the presence of Mi-1.2 gene product in tomato plants does not significantly affect the reproductive potential of T. urticae. Therefore, Mi-1.2 gene cannot be a satisfying source of plant resistance to this mite-herbivore generalist.

Open access