VARIABILITY OF MAIZE GENOTYPES IN THE EXPRESSION OF TOLERANCE TO EUROPEAN CORN BORER (Ostrinia nubilalis Hbn.)

The backbone of modern technologies is the creation of tolerant genotypes at the ECB with special emphasis on the interaction between the degree of plant damage and metabolic processes as potential responses to stress. During the vegetation period of 2016 and 2018, the variability and response of four maize genotypes to the effectiveness of insecticides and bioinsecticides and the interdependence with the dynamics of the ECB population were examined. Out of a total of 11,023 attacked plants in both years of the survey, in 2016 the largest number of plants (4,841) with a broken stalk above the ear and at the height of the ear and belonged to categories C3 to C8. In 2018, there was no damage to the tassel and ear, while 3,672 plants were dominated by leaf damage and perforation in the H2 type. In addition to the fact that more infested plants were observed in the genotypes, ZP 434 and ZP 666 the categories of damage type C5, C6 and C7 were more pronounced. The foliar treatment of plants with chlorantraniliprole in two-year research proved to be the most effective with the least number of attacked plants with a high degree of damage. In contrast, bioinsecticide treatment of plants, in addition to a large number of infested plants, was dominated by high categories of damage that deviated from all other treatments as well as from control. Within the definition of the degree of tolerance of maize genotypes, the influence of treatment on changes in secondary metabolites (phytins) in seeds was observed. It was noticed that there is a trend of positive correlation between the amount of phytin in the seed (mg g-1) with the attack of moths of the first generation and the number of dissected larvae, as well as a trend of negative correlation with the percentage of attacks of the second generation. Correlation coefficients are expressed: in the genotype ZP-600, while in the genotype ZP-666 correlation is the lowest, ie. irrelevant. The obtained results may be of great importance in future work aimed at the selection of maize genotypes tolerant and resistant to corn borer attack, connected to the role of phytin, as an antioxidant and phosphorus deposited in corn grain.