Nutshell Physicochemical Characteristics of Different Hazel Cultivars and Their Defensive Activity toward Curculio nucum (Coleoptera: Curculionidae)

Hazel (Corylus avellana) is easily attacked by Curculio nucum L. To better understand the physiological mechanisms underlying different resistance of cultivars to C. nucum, we determined insect-resistant compounds, plant hormones contents, and enzyme activities in nutshells three hazel (DW, B21, MZ) before (preexisting defense) after (induced chewing. The findings demonstrated that differed significantly (p < 0.05): damage rate MZ with 17.57% was highest, followed DW (11.23%), then B21 (7.15%). contents compounds (total terpenoid, tannin, total phenol, flavonoids, cellulose, lignin) varied cultivars, both chewing, except for cellulose lignin induction. level defense hazelnut enhanced due Pearson correlation results revealed negatively correlated jasmonic acid (JA) (R2 = 0.812), SOD 0.671), salicylic (SA) 0.878), terpenoids 0.774), positively flavonoids 0.696), celluloses 0.501), POD 0.758), abscisic (ABA) 0.978). related not but ratio cellulose-to-lignin 0.703). Our suggested against attack responded improving nutshells. A particular provides most effective physical structural properties