Screening of Sugar Beet Genotypes to Beet Curly Top Virus and Sugar Beet Cyst Nematode (Heterodera schachtii)

The beet cyst nematode (BCN) (Heterodera schachtii) and beet curly top virus-severe (BCTV-Svr) (Curtovirus betae) are two important pathogens worldwide. In present study, the reaction of ۱۴ genotypes to BCN and BCTV-Svr was separately assessed, using Jolgeh and Sanetta cultivars as susceptible and resistant controls, respectively, in completely randomized design experiments. Reactions were based on the cyst and egg counts and symptoms severity index. Experiments were performed in the greenhouse of Tarbiat Modares University, Tehran, Iran, and were repeated twice independently. Based on the results of initial experiments, the S۱-۹۶۰۰۹۰, S۱-۹۴۰۳۲۴, S۱-۹۶۰۲۹۴, and S۱-۹۶۰۲۸۴ genotypes resistant to the BCN, were selected for further investigation. Furthermore, the reaction of the four selected genotypes to BCN, BCTV-Svr, and the mixture of the two pathogens was evaluated by analyzing their growth, physiological, and biochemical characteristics, and virus accumulation. Resistant genotypes showed higher levels of defense-related enzymes such as catalase, guaiacol peroxidase, and polyphenol oxidase, whereas susceptible genotypes exhibited significant reductions in photosynthesis, greenness, and chlorophyll a, b, and carotenoid content compared to non-inoculated and resistant plants. This is the first study conducted to search for dual-resistance sources against two devastating pathogens that frequently occur in the sugar beet-growing regions of Iran. Based on the results of this research, genotypes S۱-۹۶۰۰۹۰ and S۱-۹۴۰۳۲۴ were identified as resistant to both pathogens and are recommended for breeding purposes.

کلیدواژه ها:

Beta vulgaris ، Curtovirus ، Defense-related enzymes ، Dual-resistance sources ، Peroxidase ، Polyphenol oxidase