RESISTANCE TO SITODIPLOSIS MOSELLANA (DIPTERA: CECIDOMYIIDAE) IN SPRING WHEAT (GRAMINEAE)

Abstract

Cultivars of winter wheat, Triticum aestivum L., previously identified as possible sources of resistance to wheat midge, Sitodiplosis mosellana (Géhin), were crossed with spring wheat to produce lines with a spring growth habit and assure synchrony between insect and plant. Many of the lines showed low levels of infestation by wheat midge in the field, and 21 of these were tested for resistance in the laboratory. All test lines exhibited resistance, ranging from 58 to 100% suppression of larvae and 70 to 100% suppression of seed damage, compared with a susceptible line. Larval development was delayed and survival was reduced on all lines. This antibiosis was associated with a hypersensitive reaction in the seed surface. The hypersensitive reaction, or feeding damage by young larvae before they died, reduced the biomass of some infested resistant seeds by 28% compared with over 60% for infested susceptible seeds. Some lines also reduced the level of infestation either through oviposition deterrence or a resistance which prevented newly hatched larvae from establishing on the seed surface. A few lines also reduced the hatching rate of wheat midge eggs. The resistance was equally effective in field trials during two consecutive summers in Manitoba and Saskatchewan, with at least a 20-times difference in the level of infestation between susceptible and resistant wheats. No larvae could develop to maturity on some resistant lines. Large plots of one resistant line produced less than 1% as many larvae as a typical susceptible wheat, and the larvae that did survive produced few, small adults. This resistance is the first documented case of a high level of true resistance to wheat midge in spring wheat, distinct from asynchrony between the insect and susceptible stage of the plant. The antibiosis component of the resistance is currently being incorporated in cultivars suitable for production in western Canada.

Susceptibility of winter wheat cultivars to wheat ear insects in Central Germany

“…On the other hand, Skalmeje cultivar has also this wm1 marker, and it is a resistant cultivar, therefore, midge's infestation was very low as confirmed by Schliephake (2009, personal communication). the low densities of wheat midge on resistant wheat in this study are consistent with those found in previous studies conducted with different objectives (Lamb et al 2000a;Smith et al 2004). Similar results were obtained by (Smith et al 2007), pointing that wheat midge developing on resistant wheat was always very low compared with that of larvae developing on susceptible wheat cultivars and also they mentioned that small numbers of S. mosellana matured larvae in each wheat cultivar carrying the Sm1 gene for antibiosis resistance against this insect.…”

“…resistance to the wheat midge is partially dominant due to expression of the Sm1 resistance as single gene , that mediates an induced hypersensitive response in the surface of developing seeds where wheat midge larvae begin feeding, resulting in larval death (Ding et al 2000;lamb et al 2000a). in the wheat midge, the resistance act as an antibiotic reaction that includes elevation of phenol compound levels and results in the death of the young larvae shortly after they begin feeding (Ding et al 2000;Harris et al 2003).…”

Oviposition Preference and Offspring Performance of a Wheat MidgeSitodiplosis mosellana(Géhin) (Diptera: Cecidomyiidae) on Defended and Less Defended Wheat Plants

“…Laboratory experiments were conducted on three wheats: the cultivar ÔRoblinÕ that is highly preferred for oviposition and suitable for larval development (Lamb et al 2000a); the cultivar ÔSuperbÕ that is less preferred for oviposition in the laboratory than ÔRob-linÕ but susceptible to infestation in the Þeld ; and the breeding line ÔKey 97Ð10Õwhich is not preferred for oviposition either in the laboratory and the Þeld, and is antibiotic for larval development (Lamb et al 2000a. The previously published ovipositional preferences were identiÞed in multi-line screening trials that did not consider plant developmental stages.…”

“…Wheat midge females prefer to oviposit at particular plant growth stages (Ding and Lamb 1999), and on some wheat genotypes (Lamb et al 2000a. Wheat defends itself against larval feeding in at least two ways: 1) the feeding site is suitable for larvae only at an early stage of seed development (Ding and Lamb 1999); 2) some wheat genotypes exhibit a hypersensitive reaction that kills feeding larvae, even on seeds at a stage that is normally suitable for their development (Lamb et al 2000a). Both defenses are associated with increased production of phenolic acids by the plant, acting in a dose dependent way on the survival of feeding larvae.…”

“…When eggs hatch in Ϸ3 d, each larva crawls into a ßoret and initiates feeding on the surface of the seed as it begins to develop (Lamb et al 2000b). Wheat midge females prefer to oviposit at particular plant growth stages (Ding and Lamb 1999), and on some wheat genotypes (Lamb et al 2000a. Wheat defends itself against larval feeding in at least two ways: 1) the feeding site is suitable for larvae only at an early stage of seed development (Ding and Lamb 1999); 2) some wheat genotypes exhibit a hypersensitive reaction that kills feeding larvae, even on seeds at a stage that is normally suitable for their development (Lamb et al 2000a).…”