ABSTRACT
Columbia root-knot nematode, Meloidogyne chitwoodi Golden et al., was identified from potatoes, Solanum tuberosum L., collected from Nigde Province, Turkey in September 2006. Seed potatoes are the most likely source for this introduction. The nematode is currently found to be infecting potatoes grown in the Netherlands, Portugal, Belgium, Germany, the United States, Mexico, South Africa, and Argentina. M. chitwoodi acquired a quarantine status in Europe (1) because of its potential to become established worldwide and its high damage probability. Some countries prohibit import of both seed and table stock potatoes originating in states known to harbor M. chitwoodi. Lesions on the potatoes had discrete brown coloration with white central spots in the outer 1 cm of the tuber flesh. Female nematode densities averaged 3 to 5 per cm2 of a potato section beneath the lesions. Nematodes were morphologically identified as M. chitwoodi based on the perineal pattern of mature females and the tail shape of juveniles. Using PCR-restriction fragment length polymorphism of the 18S region (3) and the mtDNA COII-16S rRNA region (2) and intergenic spacer region between the 5S and 18S genes (4), individual juveniles were identified as M. chitwoodi based on their restriction fragment patterns. To our knowledge, this is the first report of Columbia root-knot nematode infecting potatoes in Turkey. The distribution of this nematode in potato fields throughout Turkey should be determined. References: (1) L. J. M. F. Den Nijs et al. Nematology 6:303, 2004. (2) T. O. Powers and T. S. Harris. J. Nematol. 25:1, 1993. (3) T. O. Powers et al. J. Nematol. 37:226, 2005. (4) J. Wishart et al. Phytopathology 92:884, 2002.
ABSTRACT
The Cereal Cyst Nematodes (CCNs) are a group of several closely related species which have been documented to cause economic yield loss on rainfed wheat production systems in several part of the world including North Africa, West Asia, China, India, Australia, America and several countries in Europe. The most commonly reported species is Heterodera avenae, however there are at least two other species H. filipjevi and H. latipons are implicated. It is well appreciated that plants under water and nutrient stress suffer greater yield loss. Control of CCNs requires maintaining nematode populations below economic thresholds. Chemicals are not environmentally sustainable or economic and the major emphasis on control has been with host genetic resistance applied with other integrated pest managent options. Unfortunately due to the number of species and pathotype variation genetic control of Cereal Cyst Nematode with plant resistance is complex. Turkey is one of the top ten wheat producers in the world and has identified these nematode as a major biotic constraint in their rainfed wheat systems. In 2001 a new joint intiative was established between CIMMYT International, the Turkish Ministry of Agriculture and (Ukurova University in Adana to understand i) the distribution of cereal nematodes on wheat; ii) assess the economic importance and improve our understanding of the population dynamics iii) culture, screen and assess known sources of resistance and identify new sources to both groups of nematodes; iv) integrate new sources of resistance into bread wheat cultivars for Turkey and International germplasm using conventional and molecular tools; v) investigate other integrated control options such as rotation and different wheat management strategies and finally vi) capacity build scientists to work in this important area. Some highlights of this work will be presented and the newly formed ICCNI - International Cereal Cyst Nematode Initative introduced.
