Effects of Green Husks of Hungarian-Bred Cultivars on Their Walnut Bacterial Blight Susceptivity

  • Géza BUJDOSÓ Research Centre for Fruit Growing, Hungarian University of Agriculture and Life Sciences, Budapest, 1223, Hungary
  • Éva LENGYEL-KÓNYA Food Science Research Group, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Budapest, 1118, Hungary
  • Mária BERKI Food Science Research Group, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Budapest, 1118, Hungary
  • Anita VÉGH Institute of Plant Protection, Buda Campus, Hungarian University of Agriculture and Life Sciences, Budapest, 1118, Hungary
  • Laurine KITHI Research Centre for Fruit Growing, Hungarian University of Agriculture and Life Sciences, Budapest, 1223, Hungary
  • Nóra ADÁNYI Food Science Research Group, Institute of Food Science and Technology, Hungarian University of Agriculture and Life Sciences, Budapest, 1118, Hungary
Keywords: phenolic compounds, Hungary, fruit development, state-approved cultivars, walnut blight immunity test, walnut phenology

Abstract

The Persian walnut (Juglans regia L.) is one of Central Europe's most grown nut trees. In the green husks of walnuts, among the most important bioactive compounds are phenolics (hydroxybenzoic acids, hydroxycinnamic acids, flavonoids, naphthoquinones), which play an important role in the plant defense mechanisms against stress caused by various pathogens e.g., Xanthomonas arboricola pv. juglandis, furthermore mentioned as Xaj. The study examined the full Hungarian walnut assortment to detect the difference in phenolic profiles of their green husk and the relationship between the concentration of phenolic compounds, as well as their effects on tolerance against Xaj. All the phenological stages were recorded by Ctifl scheme. The phenolic compounds were determined by HPLC-DAD-ESI-QDA method, after which susceptibility test was carried out. The results show that concentration of the phenolic compounds varied by cultivars; it was higher in the locally-bred cultivars compared to ‘Chandler’, a more widespread cultivar. Phenolic compounds inhibited the artificial Xaj infection in the green husk. This effect had a strong correlation with the high phenols’ concentration, except for ‘Bonifác’. It is likely that the phenolics’ concentration in the walnut green husk has an important role in their defense against Xaj infection.

Published
2024-05-15