Early detection of graft-incompatibility in hawthorn (Crataegus azarolus L.) trees on apple, pear, and quince rootstocks

Aim of study: This study was conducted to determine the usability of some clonal rootstocks of apple (MM 106 and MM 111), pear (Fox 11), and quince (Quince A) for hawthorn trees propagation. Area of study: Fruit Research Institute, Isparta and Hatay Mustafa Kemal University, Hatay, Türkiye. Material and methods: ‘Sultan’ hawthorn cultivar was budded on the following clonal rootstocks: pear Fox 11, quince A, and apple MM 106 and MM 111. Plants of hawthorn seedlings (Crataegus azarolus L.) budded with ‘Sultan’ cv. were used as control. External visual diagnosis of the scion-rootstock graft combinations was performed by observing visual symptoms in budded trees growing in nursery conditions, as well as anatomic and histological investigations of the incompatibility in the laboratory. Main results: In this study, healthy scion development and callus tissue in the graft region were formed in the seedling rootstock as well as on Fox11 and Quince A clonal rootstocks. In contrast, MM 106 and MM 111 apple rootstocks showed incompatibility symptoms, with insufficient scion vigor and unstructured callus tissue development. Research highlights: ‘Tanslocated’ and ‘located’ graft incompatibility symptoms were observed in Sultan/MM 106 and Sultan/MM 111 combinations. Further studies are necessary to confirm the early good compatibility found in nursery conditions, testing the effect of those clonal rootstocks from different species (Fox11 and Quince A) on vigor, yield, and fruit quality traits in orchard conditions.