Proteins extracted from the wheat

In terms of total production tonnages used for food, wheat is currently second to rice as the main human food crop and is the leading source of vegetable protein in human nutrition (Nutrient Data Laboratory). Aphids (Order Hemiptera) are major insect pests of world agriculture, damaging crops by removing photoassimilates and vectoring numerous plant viruses (Smith and Boyko, 2007). The grain aphid (Sitobion avenae) is considered a serious pest of commercial wheat in the UK. Many aphid species can develop resistance to insecticides (Devonshire and Field, 1991), and restrictions on the availability of active ingredients for insecticide production in Europe (European Directives 91/414/EEC) has prioritized research on crop varieties with resistance to aphid pests in UK agriculture (Painter, 1951; Panda and Kush, 1995; Smith, 2005). Most commercial wheat varieties have very little resistance to aphid pests (Lee, 1984; Dedryver and Di Pietro, 1984; Di Pietro and Dedryver, 1986; Migui, 2002; Migui and Lamb, 2003), with at best partial antibiosis, antixenosis and tolerance in some winter varieties (Lowe, 1984a; Lowe, 1984b; Havlícková, 1993). Wheat genetics are more complicated than that of most other crop species. Some wheat species are diploid, with two sets of chromosomes, but many are stable polyploids, with four sets of chromosomes (tetraploid) or six (hexaploid). Modern wheat varieties grown in the U.K. are hexaploid and have low genetic diversity for insect resistance traits (Ferry et al, 2011; Ogbonnaya et al, 2013; niab.com).