Interaction of two neonicotinoid insecticides and Lr genes focusing wheat growth and residues

Seedlings of ten Lr near-isogenic lines (NIL) and four wheat lines with enhanced resistance to Puccinia triticina were treated with overdosed neonicotinoid insecticides. The enzyme of Lr 20 gene accelerated thiacloprid degradation while Lr 29 gene accelerated thiamethoxam degradation according to NILs upper plant parts lengths reduction by 6% or 10% six days after the last of three daily treatments. Lr 27 and Lr 33 effects were intermediate on thiamethoxam but only in the driest conditions. Among other NILs the growth was increased 1–5% by N faster release of S or Cl. The accumulation of Lr 20 and Lr 9 facilitated treatment in the late grain filling period when the amount of their circled residues in seed was permissible. In semiarid regions, when thiamethoxam was applied before June, respecting the adequate leaf area duration of prevalent varieties, interaction with Lr 29 could be also practical through simultaneous release of fungi reducing elements.