Role of phenolics in resistance of maize grain to the stored grain insects, Prostephanus truncatus (Horn) and Sitophilus zeamais (Motsch.) (original) (raw)
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The mechanism of resistance in maize to the stored product insects such as the maize weevil (MW), Sitophilus zeamais Motsch and the larger grain borer (LGB), Prostephanus truncatus Horn has been investigated in relation to secondary chemistry and other biochemical and physical characteristics of maize genotypes. Performance parameters of weevils (number of eggs laid, number of progeny, Dobie index, grain consumption) were negatively and significantly correlated (r = -0.8, P = 0.05) to the most abundant phenolic of grain, E-ferulic acid. With P. truncatus, the weight loss of grain also showed a negative correlation with E-ferulic acid while percent damage of kernels by insects was negatively correlated to p-coumaric acid. These phenolic acids were found in highest concentration in the pericarp and cell walls of the endosperm by fluorescence microscopy. Phenolic acid content was also found to correlate strongly with hardness of the grain, which may be related to the mechanical contributions of phenolic dimers to cereal cell wall strength. In the aleurone layer phenolic acid amines have been detected that have toxic effects on insects.
Journal of Chemical Ecology, 1990
The (E)-ferulic acid content of the grain of nine populations of land races of maize derived from CIMMYT's collections was found to be negatively correlated to susceptibility characteristics towards the maize weevil Sitophilus zeamais. Correlation coefficients for six susceptibility parameters and (E)-ferulic acid content'were significant and ranged from -0.58 to -0.79. A multiple regression analysis by the SAS forward procedure using the primary seed characteristics associated with susceptibility indicated that the ferulic acid content was the only significant factor in explaining variation in at least two susceptibility parameters: the Dobie index and adult preference. In 15 CIMMYT pools, correlations between four susceptibility parameters and (E)-ferulic acid content were also significant (-0.76 to -0.81). The results suggest that phenolic acid content is a leading indicator of grain resistance or susceptibility to insects and may represent a newly identified mechanism of resistance. a Land race. hAbbreviations: W = white, Y = yellow, F = flint, D = dent, H = highland, T = tropical, S = subtropical, L = late, I = intermediate, E = early.
PLOS ONE, 2020
Maize (Zea mays L) is one of main nutrients sources for humans and animals worldwide. In Africa, storage of maize ensures food resources availability throughout the year. However, it often suffers losses exceeding 20% due to insects such as the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera; Bostrichidae), major pest of stored maize in the tropical countries. This study aims to select resistant varieties to reduce maize storage losses and explain the physicochemical parameters role in grains susceptibility. In the first study, maize grains were artificially infested under no-choice method with insects. Susceptibility parameters such as weight loss, grain damage, number of emerged insects, median development time and susceptibility index varied significantly through maize varieties. Dobie susceptibility index (SI) was assessed as a major indicator of resistance. The most resistant varieties were Early-Thaï, DMR-ES and Tzee-Yellow. Conversely, Synth-9243, Obatampa and Synth-C varieties were susceptible. SWAN, Across-Pool and Tzee-White were classified as moderately resistant varieties. The insect reproductive potential was significantly different in the nine maize varieties and Early-Thaï, DMR-ES and Tzee-Yellow varieties were the least favourable host. To assess the relationship between grains physicochemical characteristics and varietal susceptibility, moisture, total phenolics, palmitic acid, proteins, amylose, density and grain hardness were evaluated according to standardized methods. Palmitic acid, SI, insects emerged and grain damage were significantly and positively correlated with each other, and negatively correlated with grains hardness, phenolics and amylose contents. Maize susceptibility index was significantly and negatively correlated to amylose, and phenolics contents and positively correlated to palmitic acid content. This
BASE, 2021
Description of the subject. Maize (Zea mays L.) is a major staple food providing nutrients for humans and animals worldwide. In Sub-Saharan Africa, maize is stored to ensure food resource availability throughout the year. However, stored-product pests such as the maize weevil, Sitophilus zeamais (Motsch.) (Coleoptera; Curculionidae) can cause huge grain losses. Objectives. This study aimed to assess the oviposition preference of Sitophilus zeamais over maize varieties commonly cultivated in Senegal and the effect of grain morphophysical and biochemical characteristics on their susceptibility to the maize weevil. Method. Twenty-five S. zeamais pairs (M/F) were placed in the center of an arena at equal distance of small heaps of maize grains (30 g) from nine maize varieties. Adult abundance, damaged grains, grain weight loss, and progeny were confronted to grain characteristics (phenolics and ferulic acid content, hardness, brightness, color and size of grains). Results. Susceptibilit...
2011
The study examines change in the proximate composition of maize grains infested by varied population of maize weevil (Sitophilus zeamais). 50 gm maize grains (SUWAN-1) was weighed into 250 cm3 Kilner glass jars and separately infested with 5pairs, 10 pairs and 15 pairs of S. zeamais for ninety days. A 250 cm3 Kilner jar filled with 50 gm uninfested maize grains served as control. All treatments and control were replicated four times and arranged on the work-table in the laboratory using completely randomized design. At 90 day post-infestation of the maize grains, data were collected on damage indices such as % grain weight loss, % grain damage, weight of grain dust and final population of S. zeamais. The proximate composition of the damaged and undamaged maize grains was determined by analyzing the maize grains for total protein, fat, starch, sugar, moisture and ash contents using the standard analytical method (AOAC, 1970). The data on proximate analysis was correlated with final p...
2021
Description of the subject. Maize (Zea mays L.) is a major staple food providing nutrients for humans and animals worldwide. In Sub-Saharan Africa, maize is stored to ensure food resource availability throughout the year. However, stored-product pests such as the maize weevil, Sitophilus zeamais (Motsch.) (Coleoptera; Curculionidae) can cause huge grain losses. Objectives. This study aimed to assess the oviposition preference of Sitophilus zeamais over maize varieties commonly cultivated in Senegal and the effect of grain morphophysical and biochemical characteristics on their susceptibility to the maize weevil. Method. Twenty-five S. zeamais pairs (M/F) were placed in the center of an arena at equal distance of small heaps of maize grains (30 g) from nine maize varieties. Adult abundance, damaged grains, grain weight loss, and progeny were confronted to grain characteristics (phenolics and ferulic acid content, hardness, brightness, color and size of grains). Results. Susceptibilit...
Relationship between Chemical and Physical Parameters of Maize Varieties and …
Southwestern …
Fourteen varieties of maize were analyzed for physical and chemical characteristics to study their relationship with susceptibility to maize weevil, Sitophilus zeamais (Motschulsky). Free-choice and no-choice tests were carried out at 27°C and 70% relative humidity. The susceptibility of maize varieties to attack by maize weevil was not related to grain hardness nor chemical composition. Insects selected softer and harder varieties for oviposition. The number of damaged grains was positively correlated with insect emergence. Germination was less in varieties susceptible to the insect. No α-amylase inhibitors were detected in the maize varieties.