Resistance of spring wheat against Pratylenchus thornei Sher et Allen (Tylenchida: Pratylenchidae)

In this study the yield loss of root lesion nematode (Pratylenchus thornei Sher et Allen) was investigated under natural field conditions in Adana. Under controlled laboratory conditions a P. thornei resistance assay for wheat was optimized, and 181 spring wheat varieties/lines were screened. The genetic control and location of two known different resistant sources (AUS4930 7.2 and the synthetic hexaploid wheat line, CROC_1/AE.SQUARROSA (224)//OPATA) was investigated using phenotypic and molecular methods.Under field conditions P. thornei caused a maximum of 19.85% yield loss on susceptible wheat variety Gatcher. Greenhouse resistant assay experiments showed clear differentiation between the resistance and susceptible cultivars 9 weeks after inoculation with an initial density of 400 P. thornei/plant in sandy based soil (70:29:1 sand: field soil: organic matter) in small tubes (1.5 x 100 mm) using a bottom up irrigation system with perlite. The genetic study using molecular tools revealed the resistance in both sources is quantitative and additive. The chromosomal location of P. thornei resistance in AUS4930 7.2 was found on chromosomes 1B, 2B and 6D. Similarly, the 1B chromosome was found in the CROC_1/AE.SQUARROSA (224)//OPATA, in addition to 3B, however no resistance locus located on chromosome 6D was detected.