When good pulses turn bad: root-lesion nematodes in the northern grain region of Australia

Abstract

Northern region grain growers love pulses but they hate the root-lesion nematodes that attack their crops. Unfortunately pulses such as chickpea, mungbean and faba bean, are susceptible to the root-lesion nematode, Pratylenchus thornei, and cause populations of these nematodes to increase. Three-quarters of grain paddocks in the northern grain region have P. thornei and they can cause devastating yield losses of up to 70% in intolerant wheat cultivars and up to 20% in chickpea (1, 2, 3). Successful management relies on the combination of growing tolerant cultivars that do not suffer yield loss and rotation with resistant crops that do not allow the nematodes to reproduce. Decreasing populations of P. thornei by growing consecutive resistant crops over
several years is a slow process but one that allows growers to diversify crop choices, improve yields and restore balance to the soil’s biology.
We have previously shown that populations of P. thornei in field experiments increased from two to eight-fold after growing chickpea, faba bean and mungbean cultivars and caused up to 67% yield loss in the following wheat crop. We will present new results that show there are a small number of cultivars or advanced lines with moderate resistance however, most chickpea, faba bean and mungbean cultivars remain susceptible to very susceptible.
Our research has the potential to identify new sources of resistance to root-lesion nematodes that could be incorporated into breeding programs. If there were more resistant cultivars, pulses could play a central role in helping to reduce the burden of root-lesion nematodes in northern grain region soils. Only then will our growers be able to take full advantage of all of the benefits that pulses offer our farming systems.