Mechanisms and parameters of spring rape resistance to major pests
Keywords:pest, pollen beetle, Meligethes aeneus, cruciferous flea beetle, Phyllotreta, plant immunity, tolerant variety
Immunogenetic barriers are revealed based on a study of the interaction between cruciferous flea beetles and rape blossom weevil and host plants; the barriers cause resistance of spring oilseed rape to each and both species of those pests. Thus, the mechanism of morphological barrier, which determines the resistance of rape to pollen beetle, is the structure of inflorescences in the period of budding due to compact arrangement of buds in the inflorescence that prevents the pest penetration inside the buds, which significantly reduces its harmfulness. The mechanisms of resistance of spring rape to cruciferous flea beetles are the epicuticular wax on cotyledons in the phase of seedlings, the thickness of leaf blade and upper epidermis, the size of conducting bundle, as well as the distance from the latter to upper surface of the sheet. Physiological and oxidative barrier mechanisms are the low content of substances of the secondary metabolism of plant glucosinolates, determining the combined resistance of spring rapeseed to both cruciferous flea beetles and rapeseed pollen beetle. Reparative barrier mechanism is the ability of resistant varieties to restore the lost leaf surface or buds in case of damage. Based on the identified immunogenetic barriers, a conceptual model of spring rape varieties resistant to cruciferous flea beetles and rapeseed pollen beetle is developed.