Genetic variation in resistance to Pratylenchus neglectus in wheat and triticales

The root lesion nematode Pratylenchus neglectus occurs throughout the South Australian cereal belt, where it potentially contributes to yield loss. Genetic material was examined for resistance to P. neglectus, and included 2 susceptible local commercial wheat varieties (Spear, Molineux), 2 derivatives from Spear (RAC 613-27, RAC 613-47), wheat varieties varying in reaction to I? thornei, rye and rye derivatives, triticales, and 1R substitution lines in Chinese Spring. Seeds were surface-sterilised and germinated, and 3-day-old seedlings were inoculated with about 250 larvae and 150 eggs. Plants were grown in pots containing pasteurised soil and transferred to a controlled temperature waterbath at 22 � 1�C. After 7 weeks, nematodes were extracted and counted. A significant difference for the number of nematodes per plant and per gram dry root was found between the 3 main groups of genetic material: the wheat varieties, the substitution lines, and lines with the whole genome of rye (including triticales). The triticales Abacus and Muir showed the lowest number of nematodes (per gram root and per plant). None of the wheat varieties was resistant, so genetic mechanisms conferring resistance or tolerance to P. thornei are not effective against P. neglectus.