Physiological and growth responses of cucumber (Cucumis sativus L.) genotypes to Egyptian broomrape (Phelipanche aegyptiaca (Pers.) Pomel) parasitism

Lack of consensus on effective approaches for Egyptian broomrape ( Phelipanche aegyptiaca ) management in host plants has focused attention on the identification of resistant or tolerant genotypes by evaluating plant physiological responses to parasitism. In the current study, the response of 35 cucumber ( Cucumis sativus L) genotypes to Egyptian broomrape parasitism was investigated in a completely randomized design with 4 replications. Parasitism by Egyptian broomrape led to a significant decrease in shoot and root dry weight of C. sativus compared to the control treatment which varied across different genotypes. Parasitism resulted in significant but variable increases in hydrogen peroxide, malondialdehyde, protein and phenolic compound content across all genotypes. Catalase-specific activity, ascorbate peroxidase and peroxidase in Egyptian broomrape-infected treatments also differed to that in control treatments. In addition, underground attachments number plant −1 (UAN), emerged spikes number plant −1 (ESN), total attachment number plant −1 (TAN), attachment dry weight (g)/plant −1 (ADW) were significantly different among various cucumber genotypes. As a result of our analysis, genotypes were classified into four clusters. The Khassib greenhouse genotype was different to other genotypes with increases in total phenolic compound content and catalase activity being higher compared to the other three clusters. At the same time, shoot dry weight losses, malondialdehyde enhancement and UAN traits in Khassib had the lowest values compared to the other genotypes when parasitized by broomrape.