Silicon amendments reduce aphid numbers and improve yield of aphid-resistant and susceptible wheat cultivars in a dose-dependent manner

Abstract

Silicon (Si) is a non-essential element for plant growth and development that can increase plant resistance to insect pests in both susceptible and constitutively resistant cultivars. Three field experiments were carried out testing wheat cultivars with different levels of constitutive resistance to the aphid Sitobion avenae to evaluate the effect of Si application to the soil on the pest aphid's numbers and yield. The first field experiment (2012) was carried out with the wheat cultivars BRS 254, BRS 264 (both susceptible) and BRS TIMBAÚVA (resistant to S. avenae). The second (2014) and the third field experiment (repeated twice in 2015) evaluated the effect of Si doses (50, 100, 150 and 200 kg of Si ha−1) in BRS 254 and BRS TIMBAÚVA (in the second experiment in 2014), and in BRS 254 (in the third experiment). The three wheat varieties tested were responsive to silicate amendment, yielding higher grain weight, more grains per ear, and a higher percentage of Si in the shoot following Si soil amendment. Higher levels of Si in the soil had a linear relationship with increased grain yield and had a quadratic relationship with lower aphid numbers, both in the resistant variety (BRS Timbaúva) and in all tests with the susceptible variety (BRS 254). The application of Si to the soil increased productivity and increased resistance in wheat cultivars with varying levels of resistance. Si amendment is a potential tool for management of S. avenae in wheat.