Resistance of Some Tomato Species to Orobanche Aegyptiaca (Comparative study)

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Mohammad Suleiman Sawafta
Resistance of some tomato species to Orobanche aegyptiaca.pdf930.3 KB

 This study was conducted to compare the level of resistance to Orobanche aegyptiaca in a collection of wild and cultivated tomato in open field. Sixty tomato accessions (Lycopersicon spp.) and one commercial variety ‘Samara’ were used. The experiment was conducted in Jenin District, Palestine during the 2009 growing season. The experiment was performed in the framework of a complete randomized block design (CRBD), with three replicates. Two plants from each variety per replicate were transplanted into open field by the 20th of April 2009. No artificial inoculation with broomrape seed was done at the time of transplanting since the field known to be heavily infected with broomrape from the previous growing season when the farmer was planted it with the same commercial tomato (Samara). Three traits were studied including days to first appearance of Orobanche, Weakness of tomato plants (vegetative growth) and number of emerged Orobanche per tomato plant. Moderate levels of resistance were found in some species of Lycopersicon. The susceptible tomato check was infected uniformly across the plot with emerged broomrape plants ranging from 5.8 to 6.4 shoots per tomato plant. Broomrape infection on the sixty tomato accessions used in the experiment ranged from 3.8 to 9.2, with an average of 5.7 emerged shoots per host plant compared with the susceptible tomato check, with an average of 6 emerged broomrape shoots per plant. The accessions were divided into three clusters, the first one composed of 22 accessions, the second one composed of 32 accessions and the third cluster composed of 7 accessions. Each cluster was distinguished by one or more of the measured parameters. Accessions within the first cluster could be considered as the most resistant accessions in the collection since the average number of Orobanche shoots per tomato plant was low (4.49) and at the same time tomato plants were very strong (weaknesses value = 2.26). Further histological studies to understand the mechanism of resistance in these accessions would be advisable.