Genetic Insight Into the Insect Resistance in Bread Wheat Exploiting the Untapped Natural Diversity.

Climate change is an undeniable threat to sustainable wheat production in the future as an increased temperature will significantly increase grain loss due to the increased number of generations per season of multivoltine species that are detrimental to plants. Among insects, orange wheat blossom midge (OWBM), yellow wheat blossom midge (YWBM), saddle gall midge (SGM), thrips, and frit fly (FF) are important wheat pests in the European environments, which can be managed by the development of resistant cultivars. This involves the identification, confirmation, and incorporation of insect resistance sources into new high-yielding cultivars. We used two diverse and unrelated wheat [winter wheat (WW) and spring wheat (SW)] panels to associate single-nucleotide polymorphism (SNP) markers with the mentioned pests using the tools of association mapping. All in all, a total of 645 and 123 significant associations were detected in WW and SW, respectively, which were confined to 246 quantitative trait loci. Many candidate genes were identified using the BLAST analysis of the sequences of associated SNPs. Some of them are involved in controlling the physical structures of plants such as stomatal immunity and closure, cuticular wax in leaf blade, whereas others are involved in the production of certain enzymes in response to biotic and abiotic stresses. To our knowledge, this is the first detailed investigation that deals with YWBM, SGM, thrips, and FF resistance genetics using the natural variation in wheat. The reported germplasm is also readily available to breeders across the world that can make rational decisions to breed for the pest resilience of their interest by including the resistant genotypes being reported.

Impact of sensor-controlled variable-rate fungicide application on yield, senescence and disease occurrence in winter wheat fields.

BACKGROUND: Field experiments examining target-oriented variable-rate fungicide spraying were performed in 2015 and 2016. The spray volume was adapted in real time to the local green coverage level of winter wheat (Triticum aestivum L.), which was detected using a camera sensor. RESULTS: Depending on the growth heterogeneity in the three strip trials in 2015, fungicide savings in the sensor-sprayed strip compared with the adjacent uniformly sprayed strip were 44%, 45% and 1%. In the 2016 field trial, the saving was 12%. There was no greater level of senescence or disease occurrence, and no higher yield losses in the camera-controlled variable-rate sprayed strips compared with the adjacent uniformly sprayed strips. CONCLUSIONS: From an ecological and economical point of view, sensor-controlled variable-rate spraying technology, which uses the level of green crop coverage as the plant parameter to adapt the spray volume locally, can be an alternative to the common practice of uniform spraying. © 2017 Society of Chemical Industry.

Sensor-based variable-rate fungicide application in winter wheat.

BACKGROUND: Currently, no technology for the automatic detection of diseases while moving agricultural equipment through fields is available on the market. An alternative approach of target-oriented fungicide spraying was tested to adapt the local dose rates of spray liquid in winter wheat to local differences in the plant surface and biomass by using a camera sensor. RESULTS: A linear correlation was found between the sensor values and two plant parameters, namely the leaf area index and biomass. The spray volume was linearly adapted to the local sensor value in a field trial. The camera sensor was used to operate the dosing system (gauge) at the field boom sprayer. A total of 8% of spray liquid was saved compared with common uniform spraying. CONCLUSIONS: Because no differences exist in yield and disease incidence between the sensor-based and uniformly sprayed plot, this new technology, which uses plants as targets for fungicide dosages, could be an alternative to the present common dosage practices on a hectare basis. © 2016 Society of Chemical Industry.

Jasmonic acid induces resistance to economically important insect pests in winter wheat.

BACKGROUND: Insect damage induces chemical changes in plants, and frequently these changes are part of a defensive response to the insect injury. Induced resistance was activated in winter wheat using a foliar application of synthetic jasmonic acid. Field trials were conducted to observe effects of jasmonic acid application on some wheat insects. Two wheat cultivars (Cubus and Tommi) were sprayed twice at growth stages (GS) 41 and 59 with two concentrations of jasmonic acid, along with control plots that were sprayed with water. RESULTS: There was a significant difference in the number of thrips and wheat blossom midges (WBM) among treatments in both cultivars. Plants in control plots had higher numbers of thrips and midges than in treated plots. There were higher numbers of thrips in the Tommi cultivar than in the Cubus cultivar, while the latter had higher numbers of WBM larvae than the Tommi cultivar. There was a positive correlation between WBM numbers and infested kernels in both cultivars. This study also indicated that jasmonic acid enhances the wheat yield in sprayed plots compared with control plots. CONCLUSIONS: The results indicate that jasmonic acid induced pest resistance in wheat plants and may act as a resistance mechanism of wheat against insect herbivores.