Influence of susceptible and resistant potato cultivars on the population of the potato cyst nematode Globodera rostochiensis Ro1 and on potato yields in a highly infested field in Australia

Abstract

AbstractThe potato cyst nematode, Globodera rostochiensis, is a quarantine pest in Australia affecting a relatively small number of properties in three different production areas in the State of Victoria. The effects of susceptible (Trent, Sebago and Coliban) and H1‐resistant potato cultivars (Atlantic, Crop 13 and Nicola) on nematode populations were compared in two trials in a naturally infested field in the 2008/09 season (Trial 1) and in the 2009/10 season (Trial 2). The latter included a bare fallow treatment. The reproduction factor Pf/Pi (final compared with initial nematode population) was used to determine treatment effects. Initial population density was very high, averaging 111 and 119 eggs g−1 soil in Trial 1 and 2, respectively. The Pf/Pi of population density (eggs g−1 soil) was greater after growing susceptible cultivars (average 1.74 and 2.92 in Trials 1 and 2, respectively) than after growing resistant cultivars (average 0.72 and 0.61 in Trials 1 and 2, respectively), or after a bare fallow (1.09) in Trial 2. This correlated with higher Pf/Pi values of cysts 500 g−1 soil and eggs cyst−1 for susceptible cultivars than for resistant cultivars. Average Pf/Pi values greater than one in both trials are consistent with more cysts and an increased population density after growing susceptible cultivars. There was a trend of population decline, that is, Pf/Pi < 1, after growing resistant cultivars (average Pf/Pi values of eggs cyst−1 of 0.77 and 0.35 and of eggs g−1 soil of 0.72 and 0.61, for Trials 1 and 2, respectively). However, Trial 2 showed that these Pf/Pi values were not significantly less than those for the bare fallow (0.68 eggs cyst−1 and 1.09 eggs g−1 soil). The susceptible cultivars Trent and Sebago produced lower yields than the resistant cultivars in both trials. In contrast, the susceptible Coliban yielded as well as the resistant cultivars, suggesting a high level of tolerance of this cultivar to infestation by the nematode. The resistant cultivar Crop 13 produced 34% and 36% greater total yields in Trials 1 and 2, respectively, than the once popular, but susceptible cultivar Sebago. This is the first report of the effects of potato cultivars on a population of the potato cyst nematode in an Australian field. The use of H1‐resistant potato cultivars can feasibly reduce populations of G. rostochiensis Ro1 on infested land and reduce PCN risk on land regulated as “linked” with infested land.