Genetic analysis of oviposition deterrence to orange wheat blossom midge in spring wheat.

A major QTL for oviposition deterrence to orange wheat blossom midge was detected on chromosome 1A in the Canadian breeding line BW278 that was inherited from the Chinese variety Sumai-3. Orange wheat blossom midge (OWBM, Sitodiplosis mosellana Géhin, Diptera: Cecidomyiidae) is an important insect pest of wheat (Triticum aestivum L.) that reduces both grain yield and quality.

Sex ratios of Sitodiplosis mosellana (Diptera: Cecidomyiidae): implications for pest management in wheat (Poaceae).

Sex ratios of populations of the wheat midge Sitodiplosis mosellana Gehin, developing on wheat Triticum aestivum L., were determined at reproduction, adult emergence, and dispersal. The patterns of sex ratio through the life cycle of S.

An interspersed refuge for Sitodiplosis mosellana (Diptera: Cecidomyiidae) and a biocontrol agent Macroglenes penetrans (Hymenoptera: Pteromalidae) to manage crop resistance in wheat.

An interspersed refuge of susceptible plants in a resistant, spring-sown wheat crop was tested as a strategy to protect crop resistance against evolution of virulence by the wheat midge Sitodiplosis mosellana (Géhin), and also to conserve a biocontrol agent Macroglenes penetrans(Kirby). Eight replicated field experiments were conducted using seed mixtures of 0, 5, 10, 15 and 100% or 0, 5 and 100% susceptible wheat with an agronomically similar wheat expressing the antibiotic resistance gene Sm1. The frequencies of eggs, mature larvae and parasitized larvae in susceptible and resistant wheat spikes, and midge-affected seeds in the harvest, were recorded for each plot.

The v(1)+v(3) Bands of the (16)O(17)O(16)O and (16)O(16)O(17)O Isotopomers of Ozone.

Using 0.002 cm(-1) resolution Fourier transform absorption spectra of an (17)O enriched ozone sample, an extensive analysis of the v(1)+v(3) bands of the (16)O(17)O(16)O and (16)O(16)O(17)O isotopomers of ozone has been performed for the first time. The experimental rotational levels of the (101) vibrational states were satisfactorily reproduced using a Hamiltonian matrix that takes into account the observed rovibrational resonances.

Temperature Dependence of Air-Broadening and Shift Coefficients of O3 Lines in the nu1 Band.

High-resolution Fourier transform absorption spectra of ozone broadened by dry air have been recorded at a number of temperatures from -63°C to 29°C. Using a multispectrum nonlinear least-squares procedure, we fit 29 of these spectra simultaneously to determine the air-broadening and shift coefficients and their temperature dependences for 450 lines in the 9-&mgr;m region; most of these belong to the nu1 band. Partial air-broadening results were obtained for 104 additional lines, and room-temperature self-broadening coefficients were also determined for most of the 554 lines measured.

Air-Broadening and Shift Coefficients of O3 Lines in the nu2 Band and Their Temperature Dependence.

Room temperature measurements of self- and air-broadening coefficients are reported for over 370 transitions covering a range of 0 View Article and Find Full Text PDF

Variability in life history traits of the aphid, Acyrthosiphon pisum (Harris), from sexual and asexual populations.

Many aphid species have shown remarkable adaptability by invading new habitats and agricultural crops, although they are parthenogenetic and might be expected to show limited genetic variation. To determine if the mode of reproduction limits the level of genetic variation in adaptively important traits, we assess variation in 15 life history traits of the pea aphid, Acyrhosiphon pisum (Harris), for five populations sampled along a north-south transect in central North America, and for three traits for three populations from eastern Australia. The traits are developmental times and rates as affected by temperature, body weights as affected by temperature, fecundity, measures of migratory tendency, and photoperiodic responses.

Seasonal variation in the photoperiodic responses of a pea aphid population: evidence for long-distance movements between populations.

The purpose of the study was to quantify long distance movements in populations of pea aphid, Acyrthosiphon pisum (Harris), by estimating origins and distances travelled by immigrants into a southern Manitoba population. A strong relationship was demonstrated between latitude of origin and photoperiods at which pea aphid populations are stimulated to produce the diapause stage (Smith 1987). Therefore, the approach was to use photoperiodic response as a physiological marker to identify the source of immigrant aphids.