Aggressiveness of <i>Phytophthora medicaginis</i> on chickpea: Phenotyping method determines isolate ranking and host genotype‐by‐isolate interactions

Abstract Phytophthora medicaginis causing root rot of chickpea ( Cicer arietinum ) is an important disease, with genetic resistance using C . × echinospermum crosses as the main disease management strategy. We evaluated pathogenic variation in P populations aim improving phenotyping methods for resistance. addressed question individual isolate aggressiveness across four different seedling‐based conducted glasshouses and one field‐based method. Our results revealed that a seedling media surface inoculation method used on susceptible variety moderately resistant backcross detected greatest variability among 37 isolates. Evaluations components resistance, our methods, differential pathogen–isolate reactions occur some methods. found support hypotheses level isolates depends method, interact both host genotype reactions. cup‐based showed promise non‐field‐based it provided significant correlations genotype–isolate rankings field experiment number parameters.