11 results on '"Niedz, Randall P."'
Search Results
2. Diet improvement for western corn rootworm (Coleoptera: Chrysomelidae) larvae
- Author
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Huynh, Man P., primary, Meihls, Lisa N., additional, Hibbard, Bruce E., additional, Lapointe, Stephen L., additional, Niedz, Randall P., additional, Ludwick, Dalton C., additional, and Coudron, Thomas A., additional
- Published
- 2017
- Full Text
- View/download PDF
3. ARS-Media for Excel: A Spreadsheet Tool for Calculating Media Recipes Based on Ion-Specific Constraints
- Author
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Niedz, Randall P., primary
- Published
- 2016
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4. A Dark Incubation Period Is Important for Agrobacterium-Mediated Transformation of Mature Internode Explants of Sweet Orange, Grapefruit, Citron, and a Citrange Rootstock
- Author
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Marutani-Hert, Mizuri, primary, Bowman, Kim D., additional, McCollum, Greg T., additional, Mirkov, T. Erik, additional, Evens, Terence J., additional, and Niedz, Randall P., additional
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- 2012
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5. Widespread Triploidy in Western North American Aspen (Populus tremuloides).
- Author
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Mock, Karen E., Callahan, Colin M., Islam-Faridi, M. Nurul, Shaw, John D., Rai, Hardeep S., Sanderson, Stewart C., Rowe, Carol A., Rye, Ronald J., Madritch, Michael D., Gardner, Richard S., Wolf, Paul G., and Niedz, Randall P.
- Subjects
POPULUS tremuloides ,SPECIES ,MICROSATELLITE repeats ,FLOW cytometry ,CYTOLOGY - Abstract
We document high rates of triploidy in aspen (Populus tremuloides) across the western USA (up to 69% of genets), and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species), climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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6. Combination of Multiple Resistance Traits from Wild Relative Species in Chrysanthemum via Trigeneric Hybridization.
- Author
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Yanming Deng, Jiafu Jiang, Sumei Chen, Nianjun Teng, Aiping Song, Zhiyong Guan, Weimin Fang, Fadi Chen, and Niedz, Randall P.
- Subjects
CHRYSANTHEMUMS ,POLLINATION ,GERMINATION ,PLANT hybridization ,PROGENY tests (Botany) ,PLANT embryology - Abstract
Background: With the objective of combining multiple resistant traits from wild relative species in florist's chrysanthemums, trigeneric hybridization was conducted by crossing two intergeneric F
1 hybrids Chrysanthemum grandiflorum x Artemisia vulgaris and Chrysanthemum crassum x Crossostephium chinense. Methodology/Principal Findings: To assess post-pollination phenomena, we investigated pollen germination on the stigma and embryo development, using fluorescence and scanning electron microscopy and paraffin-embedded sections, respectively. We selected eight putative trigeneric hybrid lines that showed the greatest morphological differences from the parents from among the progeny derived via embryo rescue. The hybridity of one trigeneric hybrid was further confirmed by fluorescent genomic in situ hybridization; in addition, the aphid resistance and salt tolerance of this hybrid were higher than those of the chrysanthemum parent and the C. grandiflorum x A. vulgaris F1 hybrid, respectively. Conclusions/Significance: The enhanced aphid resistance of the hybrid line reflects the inheritance of chromosomes from A. vulgaris, which carries genes that encode bioactive components. The enhanced salt tolerance of the trigeneric hybrid is attributable to inheritance of genetic materials from Chrysanthemum crassum and Crossostephium chinense, which act to maintain the compartmentation of Na+ and K+ ions and their selective transportation among different organs to avert deleterious effects and protect the photosynthetic apparatus. The results indicate that trigeneric hybridization between different bigeneric hybrids is a promising method for combination of multiple stress-resistance traits for improvement of chrysanthemum. [ABSTRACT FROM AUTHOR]- Published
- 2012
- Full Text
- View/download PDF
7. High Resolution Melting Analysis Is a More Sensitive and Effective Alternative to Gel-Based Platforms in Analysis of SSR -- An Example in Citrus.
- Author
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Distefano, Gaetano, Caruso, Marco, La Malfa, Stefano, Gentile, Alessandra, Shu-Biao Wu, and Niedz, Randall P.
- Subjects
SINGLE nucleotide polymorphisms ,MICROSATELLITE repeats ,GENETIC polymorphisms ,DNA ,CAPILLARY electrophoresis ,CITRUS - Abstract
High resolution melting curve analysis (HRM) has been used as an efficient, accurate and cost-effective tool to detect single nucleotide polymorphisms (SNPs) or insertions or deletions (INDELs). However, its efficiency, accuracy and applicability to discriminate microsatellite polymorphism have not been extensively assessed. The traditional protocols used for SSR genotyping include PCR amplification of the DNA fragment and the separation of the fragments on electrophoresis-based platform. However, post-PCR handling processes are laborious and costly. Furthermore, SNPs present in the sequences flanking repeat motif cannot be detected by polyacrylamide-gel- electrophoresis based methods. In the present study, we compared the discriminating power of HRM with the traditional electrophoresis-based methods and provided a panel of primers for HRM genotyping in Citrus. The results showed that sixteen SSR markers produced distinct polymorphic melting curves among the Citrus spp investigated through HRM analysis. Among those, 10 showed more genotypes by HRM analysis than capillary electrophoresis owing to the presence of SNPs in the amplicons. For the SSR markers without SNPs present in the flanking region, HRM also gave distinct melting curves which detected same genotypes as were shown in capillary electrophoresis (CE) analysis. Moreover, HRM analysis allowed the discrimination of most of the 15 citrus genotypes and the resulting genetic distance analysis clustered them into three main branches. In conclusion, it has been approved that HRM is not only an efficient and cost- effective alternative of electrophoresis-based method for SSR markers, but also a method to uncover more polymorphisms contributed by SNPs present in SSRs. It was therefore suggested that the panel of SSR markers could be used in a variety of applications in the citrus biodiversity and breeding programs using HRM analysis. Furthermore, we speculate that the HRM analysis can be employed to analyse SSR markers in a wide range of applications in all other species. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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- View/download PDF
8. Exploring the Natural Variation for Seedling Traits and Their Link with Seed Dimensions in Tomato.
- Author
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Khan, Noorullah, Kazmi, Rashid H., Willems, Leo A. J., Van Heusden, Adriaan W., Ligterink, Wilco, Hilhorst, Henk W. M., and Niedz, Randall P.
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SEED research ,SEED quality ,GERMINATION ,CROP yields ,SEED viability ,SEEDLINGS ,PLANT genetics - Abstract
The success of germination, growth and final yield of every crop depends to a large extent on the quality of the seeds used to grow the crop. Seed quality is defined as the viability and vigor attribute of a seed that enables the emergence and establishment of normal seedlings under a wide range of environments. We attempt to dissect the mechanisms involved in the acquisition of seed quality, through a combined approach of physiology and genetics. To achieve this goal we explored the genetic variation found in a RIL population of Solanum lycopersicum (cv. Moneymaker) x Solanum pimpinellifolium through extensive phenotyping of seed and seedling traits under both normal and nutrient stress conditions and root system architecture (RSA) traits under optimal conditions. We have identified 62 major QTLs on 21 different positions for seed, seedling and RSA traits in this population. We identified QTLs that were common across both conditions, as well as specific to stress conditions. Most of the QTLs identified for seedling traits co-located with seed size and seed weight QTLs and the positive alleles were mostly contributed by the S. lycopersicum parent. Co-location of QTLs for different traits might suggest that the same locus has pleiotropic effects on multiple traits due to a common mechanistic basis. We show that seed weight has a strong effect on seedling vigor and these results are of great importance for the isolation of the corresponding genes and elucidation of the underlying mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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9. Aerial Application of Pheromones for Mating Disruption of an Invasive Moth as a Potential Eradication Tool.
- Author
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Brockerhoff, Eckehard G., Suckling, David M., Kimberley, Mark, Richardson, Brian, Coker, Graham, Gous, Stefan, Kerr, Jessica L., Cowan, David M., Lance, David R., Strand, Tara, Zhang, Aijun, and Niedz, Randall P.
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BIOLOGICAL invasions ,POPULATION biology ,EPIPHYAS postvittana ,ALLEE effect - Abstract
Biological invasions can cause major ecological and economic impacts. During the early stages of invasions, eradication is desirable but tactics are lacking that are both effective and have minimal non-target effects. Mating disruption, which may meet these criteria, was initially chosen to respond to the incursion of light brown apple moth, Epiphyas postvittana (LBAM; Lepidoptera: Tortricidae), in California. The large size and limited accessibility of the infested area favored aerial application. Moth sex pheromone formulations for potential use in California or elsewhere were tested in a pine forest in New Zealand where LBAM is abundant. Formulations were applied by helicopter at a target rate of 40 g pheromone per ha. Trap catch before and after application was used to assess the efficacy and longevity of formulations, in comparison with plots treated with ground-applied pheromone dispensers and untreated control plots. Traps placed at different heights showed LBAM was abundant in the upper canopy of tall trees, which complicates control attempts. A wax formulation and polyethylene dispensers were most effective and provided trap shut-down near ground level for 10 weeks. Only the wax formulation was effective in the upper canopy. As the pheromone blend contained a behavioral antagonist for LBAM, 'false trail following' could be ruled out as a mechanism explaining trap shutdown. Therefore, 'sensory impairment' and 'masking of females' are the main modes of operation. Mating disruption enhances Allee effects which contribute to negative growth of small populations and, therefore, it is highly suitable for area-wide control and eradication of biological invaders. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
10. Comparative Transcript Profiling of a Male Sterile Cybrid Pummelo and Its Fertile Type Revealed Altered Gene Expression Related to Flower Development.
- Author
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Bei-Bei Zheng, Xiao-Meng Wu, Xiao-Xia Ge, Xiu-Xin Deng, Grosser, Jude W., Wen-Wu Guo, and Niedz, Randall P.
- Subjects
CITRUS ,BREEDING ,POMELO ,PRIMORDIA (Botany) ,GENE expression ,MITOCHONDRIA - Abstract
Male sterile and seedless characters are highly desired for citrus cultivar improvement. In our breeding program, a male sterile cybrid pummelo, which could be considered as a variant of male fertile pummelo, was produced by protoplast fusion. Herein, ecotopic stamen primordia initiation and development were detected in this male sterile cybrid pummelo. Histological studies revealed that the cybrid showed reduced petal development in size and width, and retarded stamen primordia development. Additionally, disorganized cell proliferation was also detected in stamen-like structures (fused to petals and/or carpel). To gain new insight into the underlying mechanism, we compared, by RNA-Seq analysis, the nuclear gene expression profiles of floral buds of the cybrid with that of fertile pummelo. Gene expression profiles which identified a large number of differentially expressed genes (DEGs) between the two lines were captured at both petal primordia and stamen primordia distinguishable stages. For example, nuclear genes involved in nucleic acid binding and response to hormone synthesis and metabolism, genes required for floral bud identification and expressed in particular floral whorls. Furthermore, in accordance with flower morphology of the cybrid, expression of PISTILLATA (PI) was reduced in stamen-like structures, even though it was restricted to correct floral whorls. Down-regulated expression of APETALA3 (AP3) coincided with that of PI. These finding indicated that, due to their whorl specific effects in flower development, citrus class-B MADS- box genes likely constituted 'perfect targets' for CMS retrograde signaling, and that dysfunctional mitochondria seemed to cause male sterile phenotype in the cybrid pummelo. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
11. Limitations to Reproductive Success in the Dioecious Tree Rhamnus davurica
- Author
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Xiuhai Zhao, Klaus von Gadow, Chunyu Zhang, Juan Wang, and Niedz, Randall P.
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0106 biological sciences ,Pollination ,lcsh:Medicine ,Flowers ,medicine.disease_cause ,010603 evolutionary biology ,01 natural sciences ,Trees ,Pollen ,medicine ,Sex Ratio ,lcsh:Science ,Path analysis (statistics) ,Rhamnus ,Multidisciplinary ,biology ,Reproductive success ,Ecology ,Reproduction ,lcsh:R ,food and beverages ,Reproductive Success ,Dioecious Tree ,Rhamnus davurica ,Understory ,15. Life on land ,biology.organism_classification ,Horticulture ,Fruit ,lcsh:Q ,Genetic Fitness ,Seasons ,Sex ratio ,010606 plant biology & botany ,Research Article - Abstract
The reproductive success of a female plant in a dioecious species may be affected by pollen limitation and resource limitation. This study presents evidence that the reproductive success of the dioecious understorey tree species, Rhamnus davurica, is affected by the distance to the nearest male. The sex ratios were female-biased, although showing fluctuations in the three years of conducting the study. The mortality rate of females was higher than that of males indicating a trade-off between reproduction and survival. Altogether 49 females, designated as “focal females”, were randomly selected for monitoring their reproductive status between April and October in 2010. But successful reproduction (meaning that the flowering female trees had fruit in the fruiting season) was observed only in 28 females in 2011 and 16 females in 2012. The method of path analysis was applied to determine the effect of topography, local competition and proximity to the nearest male on the fruit set of the females. In the three years of the study, elevation, competition and female size had no significant effect on the fruit set. The distance to the nearest male, however, had a significant effect on fruit set. Number of fruits and fruit set were decreased with increasing distance to the nearest male. It was possible to estimate maximum fruit set, based on the comparatively large dataset. The number of fruits and the fruit set are exponentially related to the distance to the nearest male and the relationships are described by an exponential model. The results of this study support the importance of pollen limitation on the reproductive success in Rhamnus davurica. peerReviewed
- Published
- 2013
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