Black oat ( Avena strigosa), white oat ( A. sativa) and Algerian oat ( A. byzantina) are extensively cultivated in the south of Brazil for grain, forage, hay and silage production, or as cover crop in no-tillage and crop-pasture integration systems. In both systems, the genotypes of oat used as cover crop must be nonhosts or poor hosts of damaging nematodes for summer cash crops. Taking into account the relevance of Pratylenchus brachyurus as a pathogen for many cash crops in Brazil, two experiments were carried out in a glasshouse in order to evaluate the host suitability of selected oat cultivars to this nematode. The initial population inoculated (Pi) were 92 specimens/plot in experiment 1, and 270 in experiment 2. At the end of experimental periods (86 days after inoculation in experiment 1 and 67 days in experiment 2), the final population (Pf) of P. brachyurus was estimated and the reproductive factor (RF=Pf/Pi) was calculated. The results demonstrated that black oat (RF=0.04-1.03) is more valuable than Algerian oat (RF=2.63-2.88) or white oat (RF=1.37-1.93) for the management of P. brachyurus.
