Potential subterranean interference of Solanum elaeagnifolium, commonly known as silverleaf nightshade, on durum wheat

Abstract

Aim of study: Silverleaf nightshade (Solanum elaeagnifolium) has evolved as an invasive weed in Greece, affecting many farmers’ fields. The potential subterranean interference of silverleaf nightshade on durum wheat growth and yield, as well as its aqueous extracts phytotoxic activity on four winter cereals were investigated. Area of study: Northern Greece. Material and methods: The phytotoxic activity of silverleaf nightshade was determined in the laboratory using a perlite-based bioassay. The interference of silverleaf nightshade on durum wheat yield components was investigated by a 3-year field experiment. Main results: The silverleaf nightshade leaves/stems or the flowers/fruits extracts were in most cases more phytotoxic than those of roots. Durum wheat and oats were more sensitive than winter wheat and barley. In the field, the incorporated summer biomass of 14-18 plants m-2 (about 4.5-4.8 t ha-1) of silver nightshade caused 14.5, 23.1, 23.3, 15.9, 17.3 and 16.9% reduction (averaged across years) in durum wheat plant number, tiller number, total fresh weight, total dry weight, ear number and seed yield, respectively, compared with the silver nightshade-free plots (control). The corresponding reductions caused by 30-34 plants m-2 (about 8.3-8.6 t ha-1) were 28.5, 41.2, 45.9, 31.5, 27.0 and 31.2%. Research highlights: The presence of aboveground silver nightshade biomass, incorporated by tillage before seeding significantly reduced the emergence, growth and yield of durum wheat. This fact could be attributed to the allelopathic effect of the weed and demonstrates the need for its control before wheat establishment to enhance wheat productivity.