Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), the fall armyworm is the most economically important maize pest in the western hemisphere. This research focused on the genetic variability of the maize host strain because there is a lack of information in this area of S. frugiperda research. Amplified fragment length polymorphism (AFLP) was used to assess the genetic variability of S. frugiperda over a large geographic area. Twenty populations were collected from the maize, one population was collected from princess tree, one population was collected from lemon tree, and one population was collected from bermudagrass. The 23 populations were from Mexico, the continental United States, Puerto Rico, Brazil, and Argentina. The objective of this research was to evaluate whether the majority of genetic variability was within populations or between populations. The AFLP results showed that the majority of the genetic variability is within populations and not between populations, indicating minor gene flow and suggesting that S. frugiperda in the Western Hemisphere are an interbreeding population.
Considering all data, the ecological fitness of shattercane × cultivated sorghum F(1) hybrids may be equivalent to the wild shattercane parent, which suggests that crop genes that are either neutral or beneficial to shattercane would persist in populations within agroecosystems.
DNA-based molecular markers may provide information about introduced weedy species that would be useful in biological weed control efforts. Chloroplast DNA restriction fragment length polymorphisms (cpDNA RFLP) and random amplified polymorphic DNA (RAPD) analysis are two DNA-based marker techniques that can provide estimates of genetic variation in native and introduced populations of weedy species. Profiles provided by these techniques could furnish the necessary information to determine the geographic origins of introduced species and provide evidence for multiple introductions. Although DNA-based markers would not necessarily identify the genetic basis for host-pest compatibility, they would enable identification of specific host genotypes. Current criteria for selecting a weedy species as a target for biological control are primarily political and economic. The importance of genetic diversity and population structure in determining the vulnerability of plant populations to insects or diseases has not been fully appreciated. Estimates of genetic diversity based on DNA marker analysis could be used as one criteria for determining which plants are targeted for biological control. The success of biological weed control efforts has been limited by the high levels of genetic diversity occurring in target weed specks and the lack of biocontrol agent and target weed compatibilities. DNA-based markers may be used to increase our understanding of these factors and contribute to the success of biological weed control by helping to target the most vulnerable species and provide more realistic expectations of the potential for success given available resources.
Lee, Donald J.; Dwiekat, Ismail M.; Harris, Steven D.; and Wedin, David A., "A DGGE-cloning method to characterize arbuscular mycorrhizal community structure in soil" (2008). Papers in Plant Pathology. 95.
In this study, the Approaches and Study Skills Inventory for Students (ASSIST) short form was used to gain insight about learning style characteristics that might influence students' use of an online library of plant science learning objects. This study provides evidence concerning the internal consistency reliability and construct validity of the Deep, Strategic and Surface scale scores when used to sort students' responses. Participants consisted of 446 resident university students (230 males, 216 females) in agricultural science courses with face-to-face instruction supplemented with web-based lessons. Cronbach's alphas for the three scales ranged from 0.65 to 0.75. The data file was submitted to a maximum likelihood factor analysis with oblimin rotation. When three factors were extracted, all 18 items loaded on the expected factors. One example of an analysis based on ASSIST scale scores is presented to show the potential of this procedure for helping with the interpretation of student comments.
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