Plant Pathology Science

Introduction: Bacterial canker caused by Pseudomonas syringae is one of the most damaging diseases in apricots. This experiment was conducted to evaluate relative resistance to the disease in 22 selected local apricot hybrids including AD507, AD405, and HS731 which were recently released as Jalil, Parsi and Shanli. Material and Methods: Evaluation methods included artificial inoculation of two-year-old seedlings in an orchard and of cut shoots in the laboratory. Initially, the pathovar identity of localP. syringae strains were determined using LOPAT and GATTa tests and three isolates were used as inoculum. The inoculation was done in the seedling stem and after one year and 1.5 years, canker length was recorded. Result: The pathovar of all isolates was identified as P. syringae pv. syringae. The longest and shortest cankers were observed in AD1033 and AC113 with averages of 34.76 mm and 8.35 mm, respectively. The cut shoot bioassay was not practical for apricots. The hybrids were classified into four groups including highly resistant, resistant, moderately resistant, and susceptible. Conclusion: AD1033, AD1042, AD940, AD811, HS210, DM101, HS203 have been classified as susceptible and should not be used in breeding programs and orchard establishment/replacement. Jalil, Parsi, and Shanli were rated as resistant, and moderately resistant, respectively.

Vahabi S, Charehgani H, Abdollahi M, Rezaei R (2021) Response of eight melon cultivars to Meloidogyne javanica. Plant Pathology Science 10(2):65-73.       Doi: 10.2982/PPS.10.2.65.

 Introduction: The Root-knot nematodes (Meloidogyne spp.) are one of the most damaging plant pathogens with a wide host range and cause major losses to agricultural crops. The use of resistant cultivars is considered a safe, economical, and effective method to control these nematodes. Materials and Methods: In the present study, eight melon cultivars namely Ahlam, 105, Tracey, Ronak, Deltagrin, Mac, Holar, and Veno were evaluated for their response to M. javanica. The seeds were planted in 2 kg pots and maintained under natural conditions in Khormuj city, Bushehr province. Seedlings at the four-leaf stage were inoculated with 5000 eggs and second-stage juveniles. The factorial experiment was conducted in a completely randomized design with five replicates. Sixty days after nematode inoculation, the plants were harvested and the plant growth and nematode population indices were evaluated. Results: The results showed that the nematode reproduction factor was significantly lower in Ronak, Deltagrin, and Veno than in the other cultivars. No significant difference was observed in shoot fresh weight of nematode inoculated and non-inoculated plants of Ronak cultivar. Conclusion: Ronak, Delta-green and Veno cultivars are less susceptible to M. javanica.