Evaluation of Apple Dwarf Cultivars Seedlings for Selection of Rootstocks Tolerant to Phytophthora cactorum, Causal Agent of Crown Rot Disease

Soroori, S.; Hajnajari, H.; Rezaie, S.; Zamanizadeh, H. R.

doi:10.22092/spij.2017.110957

Evaluation of Apple Dwarf Cultivars Seedlings for Selection of Rootstocks Tolerant to Phytophthora cactorum, Causal Agent of Crown Rot Disease

Authors

10.22092/spij.2017.110957

Abstract

Crown rot disease in some imported rootstocks is a common problem in establishment of intensive and semi-intensive orchards. Native dwarfing apple cultivars are precious genetic resources for selection of genotypes resistant to crown rot, because of their adaptability to the pedoclimatic conditions of Iran . In previous investigation vegetative and productive characters of native apple cultivars were evaluated and cultivars Azayesh, Morabbaei Isfahan, Morabbaei Kamalabad, Zinati and Northern Spy were selected as parents. The open pollinated fruits and seeds were cultivated. All the obtained seedlings, composed of five different genetic populations were inoculated wih Phytophthora cactorum isolates in a controlled condition in greenhouse. Table for defining damage severity was prepared according to the characteristic symptoms on leaves and stems. According to the damage table seedlings were classified within the six groups of susceptibility. Cultivar Morabbaei Isfahan with higher percentage of germination, lower height and adequate resistance to crown rot was selected as the best cultivar. Cultivar Zinati, inspite of lower germination percentage, showed good dwarfing characteristic and tolerance to crown rot.

Keywords