Evaluation of a DNA tool to determine risk of chickpea Phytophthora root rot

Abstract

Key findings • Increasing levels of inoculum (oospores/ plant) of Phytophthora medicaginis (P. med) was strongly correlated with the decreasing yield of YorkerA, a moderately resistant chickpea variety. • An inoculum level of 660 oospores/plant (PreDicta B® >5000 P. med copies/g soil) at sowing significantly reduced yield compared with lower inoculum levels under both dryland and irrigated conditions. • Testing soil samples from grower paddocks in 2015 confirmed earlier results, that the PreDicta B® soil P. med test can identify P. med in commercial fields. • These findings provide further evidence that the PreDicta B® P. med test will be a useful tool for growers to determine their risk of Phytophthora root rot before sowing chickpeas. • Note: the SARDI PreDicta B® test for Phytophthora medicaginis is under development and is not yet available commercially.