75 research outputs found
Differences in pheromone composition between the two strains of the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)
Erstellung eines Leitfadens zur Verarbeitung und zum Anbau von ökologischem Dinkel
Ziel des Projekts war die Stärkung der Wertschöpfungskette für in Deutschland erzeugten Dinkel. Dazu sollten Basisspezifikationen für die Qualität von Speisedinkel und Empfehlungen für Anbau und bäckerische Verarbeitung erarbeitet werden, mit deren Hilfe in der Praxis die Produktionssicherheit und Produktqualität verbessert werden können. Grundlage dafür sollten die spezifischen Eigenschaften von Dinkel im Allgemeinen sowie den untersuchten Sorten im Besonderen sein.
Zunächst wurden Praxis-Gebäckproben untersucht, um eine Zielqualität festzulegen. Darauf folgte die Untersuchung von rund 150 Praxis-Getreideproben aus ganz Deutschland. Dabei handelte es sich zur Hälfte um Dinkel der Sorte „Oberkulmer Rotkorn“, zur Hälfte um „Franckenkorn“. Bestimmt wurden die sensorischen Eigenschaften, Analysewerte sowie die rheologischen Eigenschaften. Außerdem wurden Vermahlungs- und Backversuche durchgeführt.
Ein Standardverfahren zur Entspelzung und Vermahlung von Dinkel im Labormaßstab wurde entwickelt. Verschiedene Methoden und Mehltypen wurden bewertet im Hinblick darauf, wie aussagekräftig sie in Bezug auf die Proteinqualität des Dinkels sind. Für die Charakterisierung der Backqualität wurden Öko-Standard-Backversuche sowohl für Vollkornmehl als auch für Typenmehl angepasst für Dinkel entwickelt.
Ergebnis aus dem Vergleich im Standard-Backversuch ist eine bessere Backqualität von „Franckenkorn“. „Oberkulmer Rotkorn“ zeigt stärkere Qualitätsschwankungen bei ungünstigen Witterungsverhältnissen im Anbau.
Beide Sorten lassen sich jedoch mit angepasstem Vorgehen zufriedenstellend verbacken. Hierzu wurden Optimierungsversuche durchgeführt. Variiert wurden der Verarbeitungsprozess an sich (Teigruhezeit, Temperatur), der Zutateneinsatz sowie das eingesetzte Mehl (Mischung aus beiden Dinkelsorten). Eingesetzt wurden nur Zutaten, die entsprechend den Richtlinien der deutschen Öko-Anbauverbände zulässig sind.
Für jede Probe wurden die Untersuchungsergebnisse in Verbindung mit Daten zu Standort und Anbaumaßnahmen ausgewertet. Ein Praxis-Leitfaden „Biodinkel“ wurde in der Reihe der FiBL-Merkblätter veröffentlicht
Evolution of reproductive isolation of spodoptera frugiperda
Spodoptera frugiperda, the fall armyworm, is a noctuid moth occurring in North and South America. In this species, two host strains have been identified in the late 1980s (Pashley et al. 1985; Pashley 1986), a so-called corn-strain and a so-called rice-strain. The two strains differ in mitochondrial DNA sequences in the cytochrome oxidase I (COI) and NADH dehydrogenase 1(ND1) genes. There are also strain-specific amplified fragment length polymorphisms (AFLP), restriction length fragment polymorphisms (RFLP), a so-called Frugiperda Rice (FR) repetitive nuclear DNA sequence, present in high copy number in the rice-strain and mostly lower copy number in the corn-strain and nucleotide polymorphisms within the triose phosphate isomerase gene (Tpi). Recently, sex pheromone differences have been found between populations of the two strains. However, these differences were not consistent between the studies, suggesting that geographic variation may be confounded with strain-specific variation, or that pheromones may vary within strains as well. The relative importance of the pheromone differences between the two strains still needs to be established, i.e. are males of the two strains differentially attracted to the different pheromone blends. Since other physiological, developmental, and behavioral differences have been found between the strains, in this overview we integrate strain-specific variation in sexual communication with other possible pre- and postmating barriers that are likely involved in the differentiation between the two strains.Fil: Groot, Astrid T.. University of Amsterdam; PaÃses BajosFil: Unbehend, Melanie. Instituto Max Planck Institut für Chemische Okologie; AlemaniaFil: Hänniger, Sabine. Instituto Max Planck Institut für Chemische Okologie; AlemaniaFil: Juárez, MarÃa Laura. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Kost, Silvia. Instituto Max Planck Institut für Chemische Okologie; AlemaniaFil: Heckel, David G.. Instituto Max Planck Institut für Chemische Okologie; Alemani
bric a brac controls sex pheromone choice by male European corn borer moths
The sex pheromone system of similar to 160,000 moth species acts as a powerful form of assortative mating whereby females attract conspecific males with a species-specific blend of volatile compounds. Understanding how female pheromone production and male preference coevolve to produce this diversity requires knowledge of the genes underlying change in both traits. In the European corn borer moth, pheromone blend variation is controlled by two alleles of an autosomal fatty-acyl reductase gene expressed in the female pheromone gland (pgFAR). Here we show that asymmetric male preference is controlled by cis-acting variation in a sex-linked transcription factor expressed in the developing male antenna, bric a brac (bab). A genome-wide association study of preference using pheromone-trapped males implicates variation in the 293kb bab intron 1, rather than the coding sequence. Linkage disequilibrium between bab intron 1 and pgFAR further validates bab as the preference locus, and demonstrates that the two genes interact to contribute to assortative mating. Thus, lack of physical linkage is not a constraint for coevolutionary divergence of female pheromone production and male behavioral response genes, in contrast to what is often predicted by evolutionary theory
Sexual communication of Spodoptera frugipera from west Africa: adaptation of an invasive species and implications for pest management
Open Access Journal; Published online: 19 Feb 2020The pest species Spodoptera frugiperda, which is native to North and South America, has invaded Africa in 2016. The species consists of two strains, the corn-strain and rice-strain, which differ in their sexual communication. When we investigated populations from Benin and Nigeria, consisting of corn-strain and rice-corn-hybrid descendants, we found no strain-specific sexual communication differences. Both genotypes exhibited the same pheromone composition, consisting of around 97% (Z)-9-tetradecenyl acetate (Z9–14:Ac), 2% (Z)-7-dodecenyl acetate (Z7–12:Ac), and 1% (Z)-9-dodecenyl acetate (Z9–12:Ac), they had similar electrophysiological responses, and all mated around three hours into scotophase. However, we found geographic variation between African and American populations. The sex pheromone of African corn-strain and hybrid descendant females was similar to American rice-strain females and showed higher percentages of the male-attracting minor component Z7–12:Ac. In addition, African males exhibited the highest antennal sensitivity towards Z7–12:Ac, while American males showed highest sensitivity towards the major pheromone component Z9–14:Ac. Increasing the production of and response to the critical minor component Z7–12:Ac may reduce communication interference with other African Spodoptera species that share the same major pheromone component. The implications of our results on pheromone-based pest management strategies are discussed
Geographic Variation in Sexual Attraction of Spodoptera frugiperda Corn- and Rice-Strain Males to Pheromone Lures
The corn- and rice-strains of Spodoptera frugiperda exhibit several genetic and behavioral differences and appear to be undergoing ecological speciation in sympatry. Previous studies reported conflicting results when investigating male attraction to pheromone lures in different regions, but this could have been due to inter-strain and/or geographic differences. Therefore, we investigated whether corn- and rice-strain males differed in their response to different synthetic pheromone blends in different regions in North America, the Caribbean and South America. All trapped males were strain typed by two strain-specific mitochondrial DNA markers. In the first experiment, we found a nearly similar response of corn and rice-strain males to two different 4-component blends, resembling the corn- and rice-strain female blend we previously described from females in Florida. This response showed some geographic variation in fields in Canada, North Carolina, Florida, Puerto Rico, and South America (Peru, Argentina). In dose-response experiments with the critical secondary sex pheromone component (Z)-7-dodecenyl acetate (Z7-12:OAc), we found some strain-specific differences in male attraction. While the response to Z7-12:OAc varied geographically in the corn-strain, rice-strain males showed almost no variation. We also found that the minor compound (Z)-11-hexadecenyl acetate (Z11-16:OAc) did not increase attraction of both strains in Florida and of corn-strain males in Peru. In a fourth experiment, where we added the stereo-isomer of the critical sex pheromone component, (E)-7-dodecenyl acetate, to the major pheromone component (Z)-9-tetradecenyl acetate (Z9-14:OAc), we found that this compound was attractive to males in North Carolina, but not to males in Peru. Overall, our results suggest that both strains show rather geographic than strain-specific differences in their response to pheromone lures, and that regional sexual communication differences might cause geographic differentiation between populations.Fil: Unbehend, Melanie. Instituto Max Planck Institut Fur Chemische Okologie; AlemaniaFil: Hänniger, Sabine. Instituto Max Planck Institut Fur Chemische Okologie; AlemaniaFil: Vasquez, Gissella M.. University Of North Carolina; Estados UnidosFil: Juárez, MarÃa Laura. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Tucumán; ArgentinaFil: Reisig, Dominic. University Of North Carolina; Estados UnidosFil: Mcneil, Jeremy N.. University of Western Ontario. Department of Biology; CanadáFil: Meagher, Robert L.. United States Department Of Agriculture; Estados UnidosFil: Jenkins, David A.. United States Department of Agriculture; ArgentinaFil: Heckel, David G.. Instituto Max Planck Institut Fur Chemische Okologie; AlemaniaFil: Groot, Astrid T.. University Of Amsterdam; PaÃses Bajos. Instituto Max Planck Institut Fur Chemische Okologie; Alemani
Vertebrate pheromones and other semiochemicals: the potential for accommodating complexity in signalling by volatile compounds for vertebrate management
The interaction between volatile and non-volatile, e.g. proteinaceous, components of pheromone and other semiochemical-based signalling systems presents a daunting set of problems for exploitation in the management of vertebrates, good or bad. Aggravating this is the complexity of the mixtures involved with pheromones, not only by definition associated with each species, but also with individual members of that species and their positions within their immediate communities. Nonetheless, already in some contexts, particularly where signals are perceived at other trophic levels from those of the vertebrates, e.g. by arthropods, reductionist approaches can be applied whereby the integrity of complex volatile mixtures is maintained, but perturbed by augmentation with individual components. In the present article, this is illustrated for cattle husbandry, fish farming and human health. So far, crude formulations have been used to imitate volatile semiochemical interactions with non-volatile components, but new approaches must be developed to accommodate more sophisticated interactions and not least the activities of the non-volatile, particularly proteinaceous components, currently being deduced
Plant volatile-mediated signalling and its application in agriculture: successes and challenges
The mediation of volatile secondary metabolites in signalling between plants and other organisms has long been seen as presenting opportunities for sustainable crop protection. Initially, exploitation of interactions between plants and other organisms, particularly insect pests, foundered because of difficulties in delivering, sustainably, the signal systems for crop protection. We now have mounting and, in some cases, clear practical evidence for successful delivery by companion cropping or next-generation genetic modification (GM). At the same time, the type of plant signalling being exploited has expanded to signalling from plants to organisms antagonistic to pests, and to plant stress-induced, or primed, plant-to-plant signalling for defence and growth stimulation
Rheological properties of some Croatian and German wheat varieties and their relation to protein composition
Rheological properties and protein macro fraction of ten Croatian and five German wheat varieties were studied. Differences in dough rheological properties of German and Croatian wheat varieties were analysed by ANOVA. Multiple regression was used to determine the influences of protein macro fractions of Croatian and German wheat varieties on rheological properties of their doughs. The investigation had shown that Croatian and German wheat varieties had similar dough properties. Protein content and protein composition influenced many of investigated rheological parameters. However, most of the influences were found in the mixing properties of doughs in both German and Croatian wheat varieties. Dough development time, stability and the degree of softening from the Farinograph and dough strength from the Alveograph showed the highest correlation coefficients with the protein composition. Influences of protein macro fraction of Croatian wheat varieties and influences of protein macro fraction of German wheat varieties on rheological parameters showed some differences
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