Root-Knot Nematode Resistance Genes

The Southern root-knot nematode (RKN) is the most important parasitic nematode of upland cotton, inflicting economic losses through direct damage to the plant root system and indirectly through increasing severity of other root diseases such as Fusarium Wilt. Recommended management practices to control RKN include crop rotation and nematicide application. The broad host-range of RKN leaves cotton growers with few profitable options to adopt crop rotation as a means of nematode management. Nematicides applied at planting fail to provide season long protection; and the future availability of most widely used cotton nematicide, aldicarb, is uncertain. Host plant resistance can be an efficient RKN management tool in cotton production. Resistant varieties can offer good to excellent pest control efficacy and are also environmentally sound alternatives. The slow breeding progress for developing RKN resistant cultivars is partly due to the current screening process that is tedious, time consuming and destructive for identifying resistance genotypes. Molecular marker offers an alternative screening process for identifying resistance genotypes in breeding programs. UGA crop and soil scientists are working on the development of diagnostic markers for genes conditioning RKN resistance, which will accelerate the transfer of these genes to genotypes or germplasm for new cultivar development. They found that QTL mapping identified major genes conferring resistance to RKN.