Selected Cultivar-Specific Parameters of Wheat Grain as Factors Influencing Intensity of Development of Grain Weevil Sitophilus granarius (L.)

Abstract

Wheat, the main source of protein in the human diet, is a staple food in many countries. The yields and technological quality of wheat grain depend on both the yielding potential of wheat and the properties of wheat grain that allow its safe storage. To a large extent, losses during storage are caused by storage pests. Grains of 46 wheat cultivars were used in the study (samples weighing 20 g of each variety in 10 replications), on which the development of the grain weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae) was observed (20 insects aged 3–4 days; sex ratio of 1:1). The laboratory study was carried out at constant temperature (27 OC) and humidity (75% relative humidity). The laboratory study demonstrated that the physicochemical parameters of grain (hardness, glassiness, flouriness, content of protein, sugars, starch, and crude fat), which are cultivar-dependent, can act as regulators of the development of the grain weevil. The main aim of the study was to develop recommendations regarding the breeding of wheat cultivars resistant to the foraging of S. granarius and which could therefore produce grain for longer storage, and to distinguish those that are more sensitive to the grain weevil and whose grain should therefore be supplied to the market more quickly. Knowledge of the resistance or susceptibility of individual cereal varieties to the feeding of storage pests may be useful in integrated grain storage management. Among the 46 wheat cultivars studied, five cultivars with the highest and five cultivars with the lowest susceptibility to foraging by S. granarius were identified. The highest inherent tolerance to the grain weevil was displayed by the following cultivars: KWS Livius, Bogatka, Speedway, Platin, and Julius; in contrast, the cultivars Askalon, Bamberka, Ostroga, Forum, and Muszelka proved to be the most sensitive. The chemical and physical analysis of the selected cultivars revealed a significant, positive correlation between the intensity of the development of the grain weevil, the content of starch and crude fat in the grain, and grain hardness and flouriness.