An Artificial Neural Network Model to Predict Wheat Stem Sawfly Cutting in Solid-Stemmed Wheat Cultivars

Abstract

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a major pest of wheat (Triticum aestivum L.) in the northern Great Plains of North America. The use of solid-stemmed cultivars helps mitigate crop losses and can also affect the survivorship of C. cinctus. The efficacy of a plant's resistance is based on its ability to develop pith in the culm of the stem, which is influenced greatly by interactions between the genotype and environment. Precipitation-related weather interacts with photoperiod to reduce pith expression in solid-stemmed wheat. A model that predicts pith expression could serve as a management tool to prevent losses by alerting producers if in-season precipitation patterns have caused less than ideal pith expression in a cultivar. Artificial Neural Network (ANN) models are used to make predictions for complex, non-linear systems with many co-related variables. Our objective was to improve upon past models that used regression analyses by deploying an ANN model to predict in-season stem cutting of wheat by wheat stem sawfly. Results indicate that stem cutting is influenced by the precipitation within a 5 wk period from 1 June to 5 July. These results were successfully deployed in a model that should assist with predictions of potential late season stem cutting. Deployment of this ANN model as a transferable executable file may facilitate predictions of stem cutting by wheat stem sawfly in any given year, which will empower producers to implement the appropriate harvest management strategies to reduce losses.Key words: Triticum aestivum L., host plant, bread wheat, solid-stemmed, sawfly, Cephus cinctus.Résumé : Dans le nord des grandes plaines nord-américaines, le cèphe du blé, Cephus cinctus Norton (Hymenoptera: Cephidae), est un important ravageur du blé (Triticum aestivum L.). L'usage de cultivars à tige pleine concourt à atténuer les pertes et peut affecter la capacité de survie de l'insecte. La plante résiste dans la mesure où elle réussit à produire de la moelle dans la tige, propriété qui subit considérablement l'influence des interactions entre le génotype et l'environnement. Un temps pluvieux modifiera la photopériode, ce qui réduira la synthèse de moelle chez les variétés à tige pleine. Un modèle qui prévoirait la production de moelle aurait son utilité en agronomie, car on pourrait alors éviter des pertes en signalant aux cultivateurs si les précipitations saisonnières engendrent une production insuffisante de moelle chez tel ou tel cultivar. On se sert des modèles à réseau neuronal artificiel (RNA) pour formuler des prévisions sur les systèmes complexes, non linéaires, comportant de nombreuses variables apparentées. Les auteurs voulaient améliorer les anciens modèles de prévision reposant sur l'analyse par régression en recourant à un modèle RNA pour établir l'importance des dommages causés par le cèphe au blé durant la période végétative. Les résultats obtenus indiquent que ces dommages sont influencés For personal use only.par l'intensité des précipitati...

Antixenosis, Antibiosis, and Potential Yield Compensatory Response in Barley Cultivars Exposed to Wheat Stem Sawfly (Hymenoptera: Cephidae) Under Field Conditions

“…Therefore, host plant resistance is of critical importance. Although host plant resistance that is due to the presence of solid pith in the stem can be relatively successful for reducing stem cutting in wheat ( Beres et al 2013 , Wu et al 2013 , Talbert et al 2014 , Carcamo et al 2016 , Varella et al 2016 , Adhikari et al 2018 ), solid stems may be compromised by environmental effects on pith expression ( Beres et al 2009 , 2017 ) and relative expression of the trait in different backgrounds ( Cook et al 2019 , Varella et al 2019 , Bainsla et al 2020 ). In addition to stem solidness, other defense-related metabolites, such as DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one), tricetin, and lignin are downregulated in C. cinctus -infested wheat stems when compared with uninfested stems ( Biyiklioglu et al 2018 ).…”

Comparison of Three Alleles at a Major Solid Stem QTL for Wheat Stem Sawfly Resistance and Agronomic Performance in Hexaploid Wheat

“…The solid stem trait has been found to be highly heritable ( h 2 = 0.83; Cook et al, 2018), thus making it advantageous to assess stem solidness in the absence of WSS pressure over direct selection for reduced stem cutting in WSS‐infested nurseries. Infestation for any given WSS nursery is difficult to predict due to weather patterns that cause either WSS mortality, or desynchronization of the female WSS oviposition period with plant development (Beres et al, 2017). Additionally, parasitoids that kill WSS larvae in the stem reduce WSS stem cutting in susceptible cultivars (Morrill, 1997).…”

Characterization of Resistance to Cephus cinctus (Hymenoptera: Cephidae) in Barley Germplasm

“…Host plant resistance in the form of solid-stemmed wheat cultivars has been the most successful control strategy used against this insect pest ( Beres et al 2009 , 2013 ). However, stem solidness expression is adversely affected by environmental conditions during stem elongation, which causes otherwise solid stems to become hollow ( Platt et al 1941 , Holmes et al 1959 , Beres et al 2017 ). Thus, to this date, no single control method has been demonstrated to consistently and reliably reduce WSS-related losses.…”