Influence of Plant Growth Retardants and Nitrogen Doses on the Content of Plant Secondary Metabolites in Wheat, the Presence of Pests, and Soil Quality Parameters

Wheat is the cereal most susceptible to lodging, particularly during flowering period and at early ripening stage. The use of plant growth retardants (PGRs) especially recommended when intensive nitrogen (N) fertilisation applied, which increases susceptibility plants lodging. This paper presents results tests into effects PGRs (PGR0—control; PGR1—chlormequat chloride (CCC) + trinexapac-ethyl (TE); PGR2—chlormequat ethephon (ET)), N dose—N0, N20, N40, N60 [0, 20, 40, 60 kg ha−1] on content selected secondary metabolites (PSM) in Indian dwarf wheat (Triticum sphaerococcum Percival) Trispa cultivar, abundance insect pests. In developmental stage (BBCH 39), insects were collected with an entomological net. study also investigated effect experimental factors physicobiochemical properties soil (pH KC, granulometric composition, total organic carbon TOC, TN, fractional composition humus, activity enzymes). An increase metabolite FRAP (ferring reducing ability plasma) contents following application already from as low a rate 20 ha−1 was demonstrated. A significant positive correlation noted between Oulema spp. polyphenols, chlorogenic acid, FRAP. No such relationship for Aphididae or Thysanoptera. TOC higher plots applied highest after PGRs. factor determining TN fertilisation. Soil samples PGR0 N0 treatment characterised by greatest proportion humic fulvic acid fractions smallest humin fraction. increased fraction no applied. demonstrated oxidoreductive enzymes rates. resulted inhibition compared control (PGRs0).