Impact of Cucumber Genotype on the Damages Caused by Twospotted Spider Mite and Efficiency of Biological Specimens

Abstract

Due to the growing variety of vegetables, the impact of genotypic parameters of plants on pest resistance and efficiency of biological specimens is of high importance when selecting and creating new varieties and hybrids. The researchers found out the significant differences in stability of parental forms, hybrids and cucumber varieties of the Siberian selection in relation to twospotted spider mite. The paper finds out relatively resistant parental forms - ZhL-4 and GP-61/b, and also samples of the paternal form - GF-7 and a maternal line - ZhL-9 damaged by a phytophage in a strong degree have been defined rather steady against a phytophage. High acaricidal effect of Phytoverm was found on all studied varietal samples, however the most effective biospecimen restrained development of the pest on plants of relatively resistant to phytophage of female line ZL-4. Reproduction of the twospotted spider phytoseiulus did not depend on genotypic features of parental forms, varieties and hybrids of cucumbers. The number of acarifages increased by 7.8-8.2 times in two weeks after appearance on the plants inhabited by spider mite in comparison with the initial number, as a result of which the damage rate of plants by the pest of most cultivars decreased, and in male forms practically did not change (GF-19) or slightly increased (GF-7). According to biochemical parameters, cucumber varieties with different degree of resistance to phytophage differed in dry matter content. Non-resistant to twospotted spider mite female forms LL-9, LL-12/1 and Nadezhda variety contained the lowest concentration of dry matter (5.4%), the highest amount of dry matter was observed in female line LL-4, which has the highest pest resistance (6.0%). Since the inherited traits are predominantly transmitted by the maternal component and the paternal form enhances these properties, it is important to assess not only the yield and flavour qualities but also the degree of resistance of parental forms to pests when selecting cucumber varieties and hybrids.