Population dynamics of the nematodes Heterodera glycines and Pratylenchus brachyurus in a succession crop of soybean and chickpea

The objective of this research was to evaluate the population dynamics of the nematodes Heterodera glycines race 5 and Pratylenchus brachyurus in a succession crop of soybeans and chickpeas. The experiment was carried out in Campos Novos dos Parecis, MT State, Brazil, from February to May 2017. Six chickpea cultivars were planted in February and evaluated in a naturally infested area of 60 ha. Five soil samples were collected at random in georeferenced and equidistant locations, forming a composite sample by replication. Five plants per georeferenced point and new soil samples were collected at regular intervals of about 30 d. The nematodes were extracted, identified, and counted. Data were subjected to variance and regression analyses. A reduction in the population levels of H. glycines race 5 was observed throughout the chickpea cycle, indicating that this species can be cultivated in succession with soybeans in the presence of this nematode. However, due to the maintenance in the population of P. brachyurus in the roots, rotation of soybean with chickpeas is not recommended in fields naturally infested with this nematode.