Sequential winter–summer rotations: impact on wheat and root-lesion nematode (P. thornei) populations

This dataset reports results from a 4-year field experiment at Formartin, Queensland, in which plots with high or low populations of the root-lesion nematode, Pratylenchus thornei, were prepared by growing susceptible wheat or partially resistant canaryseed (Phalaris canariensis). After an 11-month, weed-free fallow, several cultivars of eight summer crops were grown (black gram, mungbean, maize, panicum, sorghum, soybean, sunflower, Japanese millet (Echinochloa esculenta), Siberian millet (E. frumentacea), pearl millet (Pennisetum glaucum) and white French millet (P. miliaceum). Following another 15-month, weed-free fallow, P. thornei-intolerant wheat cv. Strzelecki was grown and harvested for grain at maturity. The winter crops planted in Year 1 are referred to as Phase 1 crops; summer crops planted in Year 2 and harvested in Year 3 are referred to as Phase 2 crops; wheat planted in Year 4 is referred to as the Phase 3 crop. For the Phase 2 summer crops, plant shoots were sampled to measure biomass from each plot at 3 months after planting. Before planting the Phase 1 crops, the experimental site was assessed for nematode populations from nine soil cores collected in a grid pattern. One week before planting the Phase 2 summer crops, soil cores were taken from three Phase 1 wheat and three Phase 1 canaryseed plots selected at random within each block (total of nine plots each of wheat and canaryseed). One month after removal of the Phase 2 summer crops, soil cores were taken from every plot. Prior to planting the Phase 3 wheat, soil cores were taken from plots that had been planted with the Phase 1 wheat. Populations of P. thornei were determined to 150 cm soil depth throughout the experiment using the Whitehead tray extraction method and identification and enumeration using a microscope. DNA analysis (qPCR by PreDictaB) of nematode samples was carried out on duplicate soil samples (500 g each) collected from wheat and canaryseed plots (before planting the Phase 2 summer crops). Full details of the methods are provided in the published article associated with this dataset.