Cotton (Gossypium hirsutum L.) has nectar containing modified stomates called nectaries that can be located on leaves, bracts or calyces. The nectar attracts some beneficial insects such as bees, but also predatory damaging insects such... more
Cotton (Gossypium hirsutum L.) has nectar containing modified stomates called nectaries that can be located on leaves, bracts or calyces. The nectar attracts some beneficial insects such as bees, but also predatory damaging insects such as heliothines and Lygus species. There is a naturally occurring mutation that eliminates the nectar containing nectaries and makes the cotton plants less attractive to insects. The nectariless (ne) trait is associated with a double recessive mutation of two genes (ne1 and ne2) on homeologous chromosomes 12 and 26. Expression of the trait can be variable and is also affected by environmental conditions. This makes accurately selecting for the trait based on phenotype difficult. This study identified SSR and SNP markers that can be used by breeders for marker assisted selection (MAS) of the nectariless trait. DNA markers associated with the genes conditioning the trait and used for MAS, will allow cotton cultivars to be easily developed that have decr...
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Individual matrices with numbers of different and identical SNPs for entries with the same name. These values were extracted directly from Additional file 5. Values above the diagonal represent the count of homozygous differences between... more
Individual matrices with numbers of different and identical SNPs for entries with the same name. These values were extracted directly from Additional file 5. Values above the diagonal represent the count of homozygous differences between pairs of samples. Values below the diagonal represent the number of identical SNPs genotyped between pairs. Heterozygous SNPs within samples were not counted in the number of differences between samples. SNP numbers were determined using all SNPs on the CottonSNP63K array. Five samples are included here that were identified as outliers and not used in the diversity analysis. (XLSX 17Â kb)
Results and discussion in relation to the removal of admixed/misclassified samples. Five samples were removed from overall SNP diversity analysis, and three samples were removed from the comparison of SNP and SSR data. This file presents... more
Results and discussion in relation to the removal of admixed/misclassified samples. Five samples were removed from overall SNP diversity analysis, and three samples were removed from the comparison of SNP and SSR data. This file presents the original results and discusses why the samples were subsequently removed. For the original diversity analysis, this file includes the MDS figures, Venn diagrams of unique and shared SNPs, and distribution of pairwise IBS values when these samples are included. Likewise, for the comparison of SNP and SSR data, the original principal coordinate analyses and the plots comparing SNP- and SSR-based genetic similarity are shown. (DOCX 325Â kb)
List of Gossypium samples genotyped for SNP diversity analyses. The table includes information for seed source, improved/wild classification, assigned categories for improved breeding regions, assigned categories for wild race types,... more
List of Gossypium samples genotyped for SNP diversity analyses. The table includes information for seed source, improved/wild classification, assigned categories for improved breeding regions, assigned categories for wild race types, availability of SSR genotypes for SNP-SSR comparison, and values for seed oil, protein, and seed index for samples used in GWAS analysis. In addition, for each sample, the coordinates of the first two MDS dimensions are listed for Figs. 3 and 4a, b. Five samples are included here that were identified as outliers and not used in the SNP analysis. Siokra 104–90 was not a cultivar developed in Australia (I. Wilson, personal communication). It may be a mislabeling of Siokra 1–4/649 which is actually just Siokra 1–4. (XLSX 97 kb)
Matrix showing numbers of different and identical SNPs for all pairwise combinations of 395 samples. Values above the diagonal represent the count of homozygous differences between pairs of samples. Values below the diagonal represent the... more
Matrix showing numbers of different and identical SNPs for all pairwise combinations of 395 samples. Values above the diagonal represent the count of homozygous differences between pairs of samples. Values below the diagonal represent the number of identical SNPs genotyped between pairs. Heterozygous SNPs within samples were not counted in the number of differences between samples. SNP numbers were determined using all SNPs on the CottonSNP63K array. Five samples are included here that were identified as outliers and not used in the diversity analysis. (XLSX 1032Â kb)
Successful breeding programs optimize time and resources to produce elite lines. Selecting individual plants in the F2 generation is an efficient strategy if the trait is highly heritable and nondestructive methods exist to analyze the... more
Successful breeding programs optimize time and resources to produce elite lines. Selecting individual plants in the F2 generation is an efficient strategy if the trait is highly heritable and nondestructive methods exist to analyze the seed. Cotton (Gossypium hirsutum L.) seed has limited uses because of gossypol, a toxic compound found in the seed. Gossypol exists in two enantiomeric forms with the (+) less toxic than the (−) form. Reducing gossypol or increasing the (+) enantiomer in the seed would increase the amount that could be fed to livestock, chicken, or fish. Rapid, costeffective methods were developed to measure (+) and (−) gossypol in the cotyledon (chalazal) half of a seed by high performance liquid chromatography (HPLC) on a reduced scale. Techniques were also developed to propagate the embryo (micropylar) half of the seed. The techniques were used to develop elite lines with varied gossypol levels produced one year earlier than possible with more conventional breeding...
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Gossypol is a terpenoid aldehyde found in cotton (Gossypium hirsutum L.) glands that are located throughout the plant and seed, where it serves a protective function against pests and pathogens. Cottonseed use is limited mainly to cattle... more
Gossypol is a terpenoid aldehyde found in cotton (Gossypium hirsutum L.) glands that are located throughout the plant and seed, where it serves a protective function against pests and pathogens. Cottonseed use is limited mainly to cattle feed because gossypol is toxic to most animals except ruminants. Lowering gossypol content in the seed would increase the possible uses for cottonseed. Developing new strategies to modify gossypol in cottonseed requires a better understanding of the development of gossypol containing glands. The first step is to determine when gossypol glands are initiated and filled with gossypol. Gland development was investigated using microscopic images of developing seeds from 10 glanded and two glandless cotton lines. A digital microscope with a VH-Z20R (20X to 200X) lens was used to capture developing ovule (seed) images at 14 to 22 d after flowering (DAF). One boll per plot was imaged for each DAF time point and five different sets of time intervals were col...
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Nutrients, including macronutrients such as Ca, P, K, and Mg, are essential for crop production and seed quality, and for human and animal nutrition and health. Macronutrient deficiencies in soil lead to poor crop nutritional qualities... more
Nutrients, including macronutrients such as Ca, P, K, and Mg, are essential for crop production and seed quality, and for human and animal nutrition and health. Macronutrient deficiencies in soil lead to poor crop nutritional qualities and a low level of macronutrients in cottonseed meal-based products, leading to malnutrition. Therefore, the discovery of novel germplasm with a high level of macronutrients or significant variability in the macronutrient content of crop seeds is critical. To our knowledge, there is no information available on the effects of chromosome or chromosome arm substitution on cottonseed macronutrient content. The objective of this study was to evaluate the effects of chromosome or chromosome arm substitution on the variability and content of the cottonseed macronutrients Ca, K, Mg, N, P, and S in chromosome substitution lines (CS). Nine chromosome substitution lines were grown in two-field experiments at two locations in 2013 in South Carolina, USA, and in 2...
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A new technique was developed to study the cotton fiber initiation process and fiber initial densities. The goal was to provide an additional tool to cotton breeders and geneticists interested in fiber improvement. The objectives were to... more
A new technique was developed to study the cotton fiber initiation process and fiber initial densities. The goal was to provide an additional tool to cotton breeders and geneticists interested in fiber improvement. The objectives were to assess whether fiber initiation patterns reported for some Gossypium hirsutum L. and G. barbadense L. cultivars extend to a more diverse range of cultivars/lines; and to test if there is a relationship between fiber initials density, lint percentage, and fiber characteristics. This study was performed with 17 cultivars and experimental lines of G. hirsutum (upland cotton) and G. barbadense (Pima cotton) and one G. arboreum L. accession. The ovules were extracted from flowers at the day of anthesis and 1 and 2 d thereafter, stained with a fluorescent dye, DiOC6(3) (3,3′-dihexyloxacarbocyanine iodide), and observed under a light microscope. Staining cotton fiber initials with DiOC 6(3) enabled the evaluation of a greater number of samples than the mor...
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Improved Host Plant Resistance (HPR) has long been a goal of plant breeders. Despite the fact that improvements have been made by a number of researchers over the past 50 years, chemical control of insect pests has remained the preferred... more
Improved Host Plant Resistance (HPR) has long been a goal of plant breeders. Despite the fact that improvements have been made by a number of researchers over the past 50 years, chemical control of insect pests has remained the preferred method for most production systems. The introduction of Bt cotton and the pressure to decrease insecticide use has renewed interest in increasing the plants endogenous defenses against insect pests. A number of simply inherited traits have been identified that can improve the plants defenses against various insect pests. Each individual trait is not enough to provide adequate protection, but in combination, should provide a defense network that could further reduce insecticide usage. The traits being combined include semismooth leaf (t2t2t3t3) which deters some insects from feeding and inhibits egg laying, nectariless (ne1 ne1ne2 ne2) which eliminates nectaries that can be an insect attractant, high glanding (Gl3Gl s 3) which produces glands on th...
Micronutrients are essential for plant growth and development, and important for human health nutrition and livestock feed. Therefore, the discovery of novel germplasm with significant variability or higher micronutrients content in crop... more
Micronutrients are essential for plant growth and development, and important for human health nutrition and livestock feed. Therefore, the discovery of novel germplasm with significant variability or higher micronutrients content in crop seeds is critical. Currently, there is no information available on the effects of chromosome or chromosome arm substitution in cotton on cottonseed micronutrients. Thus, the objective of this study was to evaluate the effects of chromosome or chromosome arm substitution on the variability and levels of micronutrients B, Fe, Cu, Zn, Mn, and Ni in cottonseed from chromosome substitution (CS) cotton lines. Our hypothesis was that interspecific chromosome substitution in cotton can affect cottonseed micronutrients content, resulting in significant differences and variabilities of these nutrients among CS lines and between CS lines and the controls. Nine CS lines were grown in two-field experiments at two locations (in 2013 in South Carolina, USA; and in...
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Cotton leaf curl disease (CLCuD), caused by cotton leaf curl viruses (CLCuVs), is among the most devastating diseases in cotton. While the widely cultivated cotton species Gossypium hirsutum is generally susceptible, the diploid species... more
Cotton leaf curl disease (CLCuD), caused by cotton leaf curl viruses (CLCuVs), is among the most devastating diseases in cotton. While the widely cultivated cotton species Gossypium hirsutum is generally susceptible, the diploid species G. arboreum is a natural source for resistance against CLCuD. However, the influence of CLCuD on the G. arboreum transcriptome and the interaction of CLCuD with G. arboreum remains to be elucidated. Here we have used an RNA-Seq based study to analyze differential gene expression in G. arboreum under CLCuD infestation. G. arboreum plants were infested by graft inoculation using a CLCuD infected scion of G. hirsutum. CLCuD infested asymptomatic and symptomatic plants were analyzed with RNA-seq using an Illumina HiSeq. 2500. Data analysis revealed 1062 differentially expressed genes (DEGs) in G. arboreum. We selected 17 genes for qPCR to validate RNA-Seq data. We identified several genes involved in disease resistance and pathogen defense. Furthermore, ...
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Like those of many agricultural crops, the cultivated cotton is an allotetraploid and has a large genome (~2.5 gigabase pairs). The two sub genomes, A and D, are highly similar but unequally sized and repeat-rich, which pose significant... more
Like those of many agricultural crops, the cultivated cotton is an allotetraploid and has a large genome (~2.5 gigabase pairs). The two sub genomes, A and D, are highly similar but unequally sized and repeat-rich, which pose significant challenges for accurate genome reconstruction using standard approaches. Here we report the development of BAC libraries, sub genome specific physical maps, and a new-generation sequencing approach that will lead to a reference-grade genome assembly for Upland cotton. Three BAC libraries were constructed, fingerprinted, and integrated with BAC-end sequences (BES) to produce a de novo whole-genome physical map. The BAC map was partitioned by sub genomes through alignment to the diploid progenitor D-genome reference sequence with densely spaced BES anchor points and computational filtering. The physical maps were validated with FISH and genetic mapping of SNP markers derived from BES. Two pairs of homeologous chromosomes, A11/D11 and A12/D12, were used...
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Cotton leaf curl virus disease (CLCuD) is caused by a suite of whitefly-transmitted begomovirus species and strains, resulting in extensive losses annually in India and Pakistan. RNA-interference (RNAi) is a proven technology used for... more
Cotton leaf curl virus disease (CLCuD) is caused by a suite of whitefly-transmitted begomovirus species and strains, resulting in extensive losses annually in India and Pakistan. RNA-interference (RNAi) is a proven technology used for knockdown of gene expression in higher organisms and viruses. In this study, a small interfering RNA (siRNA) construct was designed to target the AC1 gene of Cotton leaf curl Kokhran virus-Burewala (CLCuKoV-Bu) and the βC1 gene and satellite conserved region of the Cotton leaf curl Multan betasatellite (CLCuMB). The AC1 gene and CLCuMB coding and non-coding regions function in replication initiation and suppression of the plant host defense pathway, respectively. The construct, Vβ, was transformed into cotton plants using the Agrobacterium-mediated embryo shoot apex cut method. Results from fluorescence in situ hybridization and karyotyping assays indicated that six of the 11 T₁ plants harbored a single copy of the Vβ transgene. Transgenic cotton plant...
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The first epidemic of cotton leaf curl disease (CLCuD) in early 1990's in the Indian subcontinent was associated with several distinct begomoviruses along with a disease-specific betasatellite. Resistant cotton varieties were... more
The first epidemic of cotton leaf curl disease (CLCuD) in early 1990's in the Indian subcontinent was associated with several distinct begomoviruses along with a disease-specific betasatellite. Resistant cotton varieties were introduced in late 1990's but soon resistance was broken and was associated with a single recombinant begomovirus named Burewala strain of Cotton leaf curl Kokhran virus that lacks a full complement of a gene encoding a transcription activator protein (TrAP). In order to understand the ongoing changes in CLCuD complex in Pakistan, CLCuD affected plants from cotton fields at Vehari were collected. Illumina sequencing was used to assess the diversity of CLCuD complex. At least three distinct begomoviruses characterized from the first epidemic; Cotton leaf curl Multan virus, Cotton leaf curl Kokhran virus and Cotton leaf curl Alabad virus, several distinct species of alphasatellites and cotton leaf curl Multan betasatellite were found associated with CLCuD...
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Cotton germplasm resources contain beneficial alleles that can be exploited to develop germplasm adapted to emerging environmental and climate conditions. Accessions and lines have traditionally been characterized based on phenotypes, but... more
Cotton germplasm resources contain beneficial alleles that can be exploited to develop germplasm adapted to emerging environmental and climate conditions. Accessions and lines have traditionally been characterized based on phenotypes, but phenotypic profiles are limited by the cost, time, and space required to make visual observations and measurements. With advances in molecular genetic methods, genotypic profiles are increasingly able to identify differences among accessions due to the larger number of genetic markers that can be measured. A combination of both methods would greatly enhance our ability to characterize germplasm resources. Recent efforts have culminated in the identification of sufficient SNP markers to establish high-throughput genotyping systems, such as the CottonSNP63K array, which enables a researcher to efficiently analyze large numbers of SNP markers and obtain highly repeatable results. In the current investigation, we have utilized the SNP array for analyzi...
Research Interests: Microbiology, Plant Biology, Biology, Breeding, Evolution, and 15 moreMolecular Markers, Plant breeding and genetics, Medicine, Phylogeny, Identification, Cotton, Ecology and Evolutionary Biology, Germplasm, Genotype, Genetic variation, Diversity Analysis, Genetic Markers, Gossypium hirsutum, alleles, and Gossypium
The whitefly Bemisia tabaci (Genn.) is a pest and vector of plant viruses to crop and ornamental plants worldwide. Using RNA interference (RNAi) to down regulate whitefly genes by expressing their homologous double stranded RNAs in plants... more
The whitefly Bemisia tabaci (Genn.) is a pest and vector of plant viruses to crop and ornamental plants worldwide. Using RNA interference (RNAi) to down regulate whitefly genes by expressing their homologous double stranded RNAs in plants has great potential for management of whiteflies to reduce plant virus disease spread. Using a Tobacco rattle virus-derived plasmid for in planta transient expression of double stranded RNA (dsRNA) homologous to the acetylcholinesterase (AChE) and ecdysone receptor (EcR) genes of B. tabaci, resulted in significant adult whitefly mortality. Nicotiana tabacum L. plants expressing dsRNA homologous to B. tabaci AChE and EcR were constructed by fusing sequences derived from both genes. Mortality of adult whiteflies exposed to dsRNA by feeding on N. tabacum plants, compared to non-dsRNA expressing plants, recorded at 24-hr intervals post-ingestion for three days, was >90% and 10%, respectively. Analysis of gene expression by real time quantitative PCR...
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The conserved coat or V2 gene of begomoviruses is responsible for viral movement in the plant cells. RNAi technology was used to silence V2 gene for resistance against these viruses in transgenic plants. The transformation of the... more
The conserved coat or V2 gene of begomoviruses is responsible for viral movement in the plant cells. RNAi technology was used to silence V2 gene for resistance against these viruses in transgenic plants. The transformation of the RNAi-based gene construct targeting V2 gene of CLCuKoV-Bur, cloned under 35S promoter, was done in two elite cotton varieties MNH-786 and VH-289 using shoot apex cut method of gene transformation. The transformation efficiency was found to be 3.75 and 2.88 % in MNH-786 and VH-289, respectively. Confirmation of successful transformation was done through PCR in T 0, T 1, and T 2 generations using gene-specific primers. Transgenic cotton plants were categorized on the basis of the virus disease index in T 1 generation. Copy number and transgene location were observed using FISH and karyotyping in T 2 generation which confirmed random integration of V2 RNAi amplicon at chromosome 6 and 16. Real-time quantitative PCR analyses of promising transgenic lines showed...
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Cotton leaf curl disease (CLCuD) is the major biotic constraint to cotton production on the Indian subcontinent, and is caused by monopartite begomoviruses accompanied by a specific DNA satellite, Cotton leaf curl Multan betasatellite... more
Cotton leaf curl disease (CLCuD) is the major biotic constraint to cotton production on the Indian subcontinent, and is caused by monopartite begomoviruses accompanied by a specific DNA satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Since the breakdown of resistance against CLCuD in 2001/2002, only one virus, the "Burewala" strain of Cotton leaf curl Kokhran virus (CLCuKoV-Bur), and a recombinant form of CLCuMB have consistently been identified in cotton across the major cotton growing areas of Pakistan. Unusually a bipartite isolate of the begomovirus Tomato leaf curl virus was identified in CLCuD-affected cotton recently. In the study described here we isolated the bipartite begomovirus Tomato leaf curl New Delhi virus (ToLCNDV) from CLCuD-affected cotton. To assess the frequency and geographic occurrence of ToLCNDV in cotton, CLCuD-symptomatic cotton plants were collected from across the Punjab and Sindh provinces between 2013 and 2015. Analysis of the plant...
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Research Interests: Biology, Medicine, Multidisciplinary, RNA interference, Animals, and 3 moreHemiptera, PLoS one, and Whitefly
The study described here has optimized the conditions for virus-induced gene silencing (VIGS) in three cultivated cotton species (Gossypium hirsutum, G. arboreum, and G. herbaceum) using a Tobacco rattle virus (TRV) vector. The system was... more
The study described here has optimized the conditions for virus-induced gene silencing (VIGS) in three cultivated cotton species (Gossypium hirsutum, G. arboreum, and G. herbaceum) using a Tobacco rattle virus (TRV) vector. The system was used to silence the homolog of the Arabidopsis thaliana chloroplastos alterados 1 (AtCLA1) gene, involved in chloroplast development, in G. herbaceum, G. arboreum, and six commercial G. hirsutum cultivars. All plants inoculated with the TRV vector to silence CLA1 developed a typical albino phenotype indicative of silencing this gene. Although silencing in G. herbaceum and G. arboreum was complete, silencing efficiency differed for each G. hirsutum cultivar. Reverse transcriptase polymerase chain reaction (PCR) and real-time quantitative PCR showed a reduction in mRNA levels of the CLA1 homolog in all three species, with the highest efficiency (lowest CLA1 mRNA levels) in G. arboreum followed by G. herbaceum and G. hirsutum. The results indicate tha...
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Rotylenchulus reniformis is the predominant parasitic nematode of cotton in the Mid South area of the United States. Although variable levels of infection and morphological differences have been reported for this nematode, genetic... more
Rotylenchulus reniformis is the predominant parasitic nematode of cotton in the Mid South area of the United States. Although variable levels of infection and morphological differences have been reported for this nematode, genetic variability has been more elusive. We developed microsatellite-enriched libraries for R. reniformis, produced 1152 clones, assembled 694 contigs, detected 783 simple sequence repeats (SSR) and designed 192 SSR-markers. The markers were tested on six R. reniformis cultures from four states, Texas, Louisiana, Mississippi and Georgia, in the USA. Based on performance we selected 156 SSR markers for R. reniformis from which 88 were polymorphic across the six reniform nematode populations, showing as the most frequent motif the dinucleotide AG. The polymorphic information content of the markers ranged from 0.00 to 0.82, and the percentage of multiallelic loci of the isolates was between 40.9 and 45.1%. An interesting finding in this study was the genetic variab...
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Approximately 185,000 Gossypium EST sequences comprising >94,800,000 nucleotides were amassed from 30 cDNA libraries constructed from a variety of tissues and organs under a range of conditions, including drought stress and pathogen... more
Approximately 185,000 Gossypium EST sequences comprising >94,800,000 nucleotides were amassed from 30 cDNA libraries constructed from a variety of tissues and organs under a range of conditions, including drought stress and pathogen challenges. These libraries were derived from allopolyploid cotton (Gossypium hirsutum; AT and DT genomes) as well as its two diploid progenitors, Gossypium arboreum (A genome) and Gossypium raimondii (D genome). ESTs were assembled using the Program for Assembling and Viewing ESTs (PAVE), resulting in 22,030 contigs and 29,077 singletons (51,107 unigenes). Further comparisons among the singletons and contigs led to recognition of 33,665 exemplar sequences that represent a nonredundant set of putative Gossypium genes containing partial or full-length coding regions and usually one or two UTRs. The assembly, along with their UniProt BLASTX hits, GO annotation, and Pfam analysis results, are freely accessible as a public resource for cotton genomics. Be...
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High-throughput genotyping arrays provide a standardized resource for plant breeding communities that are useful for a breadth of applications including high-density genetic mapping, genome-wide association studies (GWAS), genomic... more
High-throughput genotyping arrays provide a standardized resource for plant breeding communities that are useful for a breadth of applications including high-density genetic mapping, genome-wide association studies (GWAS), genomic selection (GS), complex trait dissection and studying patterns of genomic diversity among cotton cultivars and wild accessions. We have developed the CottonSNP63K, an Illumina Infinium array containing assays for 45,104 putative intra-specific single nucleotide polymorphism (SNP) markers for use within the cultivated cotton species Gossypium hirsutum L. and 17,954 putative inter-specific SNP markers for use with crosses of other cotton species with G. hirsutum. The SNPs on the array are developed from 13 different discovery sets that represent a diverse range of G. hirsutum germplasm and five other species: G. barbadense L., G. tomentosum Nuttal ex Seemann, G. mustelinum Miers x Watt, G. armourianum Kearny, and G. longicalyx J.B. Hutchinson & Lee. The arra...
cotton (Gossypium hirsutum L.) and related species all contain gossypol, a polyphenolic com- pound that is an integral part of the cotton plant's self-defense system against insect pests and possi- bly some diseases. gossypol also has... more
cotton (Gossypium hirsutum L.) and related species all contain gossypol, a polyphenolic com- pound that is an integral part of the cotton plant's self-defense system against insect pests and possi- bly some diseases. gossypol also has been reported to have antitumor activity, medicinal effects, and contraceptive properties. However, the compound can be toxic to animals, which limits the usefulness of
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The Cotton Microsatellite Database (CMD) http://www.cottonssr.org is a curated and integrated web-based relational database providing centralized access to publicly available cotton microsatellites, an invaluable resource for basic and... more
The Cotton Microsatellite Database (CMD) http://www.cottonssr.org is a curated and integrated web-based relational database providing centralized access to publicly available cotton microsatellites, an invaluable resource for basic and applied research in cotton breeding. At present CMD contains publication, sequence, primer, mapping and homology data for nine major cotton microsatellite projects, collectively representing 5,484 microsatellites. In addition, CMD displays data for three of the microsatellite projects that have been screened against a panel of core germplasm. The standardized panel consists of 12 diverse genotypes including genetic standards, mapping parents, BAC donors, subgenome representatives, unique breeding lines, exotic introgression sources, and contemporary Upland cottons with significant acreage. A suite of online microsatellite data mining tools are accessible at CMD. These include an SSR server which identifies microsatellites, primers, open reading frames...
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Before novel transgenic plant genotypes are grown outside containment facilities and evaluated under field conditions, it is necessary to complete a risk assessment to consider the possible consequences of that release. An important... more
Before novel transgenic plant genotypes are grown outside containment facilities and evaluated under field conditions, it is necessary to complete a risk assessment to consider the possible consequences of that release. An important aspect of risk assessment is to ...
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... compass direction and distance, in order to evaluate the relative effect of bees and wind on the frequency of pollen dispersal (Table 4). Weather records showed that the prevailing wind was towards the east for 16 and to the south for... more
... compass direction and distance, in order to evaluate the relative effect of bees and wind on the frequency of pollen dispersal (Table 4). Weather records showed that the prevailing wind was towards the east for 16 and to the south for 9 of the 29 days that the plot was in flower. ...
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This paper reports the estimated gene copy number and restriction fragment length polymorphism (RFLP) map locations of five different desaturase cDNA clones from Brassica napus (oilseed rape). The desaturase enzymes encoded by four of... more
This paper reports the estimated gene copy number and restriction fragment length polymorphism (RFLP) map locations of five different desaturase cDNA clones from Brassica napus (oilseed rape). The desaturase enzymes encoded by four of these genes catalyze successive reactions that insert double bonds into lipid-linked fatty acid residues. Delta-12 (e2) and delta-15 (e3) desaturases are active in the endoplasmic reticulum,
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In this association mapping study, a tri-species hybrid, [Gossypium arboreum x (G. hirsutum x G. aridum)(2)], was crossed with MD51ne (G. hirsutum) and progeny from the cross were used to identify and map SSR markers associated with... more
In this association mapping study, a tri-species hybrid, [Gossypium arboreum x (G. hirsutum x G. aridum)(2)], was crossed with MD51ne (G. hirsutum) and progeny from the cross were used to identify and map SSR markers associated with reniform nematode (Rotylenchulus reniformis) resistance. Seventy-six progeny (the 50 most resistant and 26 most susceptible) plants were genotyped with 104 markers. Twenty-five markers were associated with a resistance locus that we designated Ren(ari) and two markers, BNL3279_132 and BNL2662_090, mapped within 1 cM of Ren(ari). Because the SSR fragments associated with resistance were found in G. aridum and the bridging line G 371, G. aridum is the likely source of this resistance. The resistance is simply inherited, possibly controlled by a single dominant gene. The markers identified in this project are a valuable resource to breeders and geneticists in the quest to produce cotton cultivars with a high level of resistance to reniform nematode.
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... rapeseed potato Reference'' FROMM et al. 1990 MiKl et al. 1990 MCSHEFFREY et al. 1992 D'HALLUIN et al. 1992 b DE BLOCK et al. 1989 WANG et al. 1992 DE BLOCK et al. 1987 D'HALLUIN et al. 1990 DE... more
... rapeseed potato Reference'' FROMM et al. 1990 MiKl et al. 1990 MCSHEFFREY et al. 1992 D'HALLUIN et al. 1992 b DE BLOCK et al. 1989 WANG et al. 1992 DE BLOCK et al. 1987 D'HALLUIN et al. 1990 DE BLOCK et al. 1987 VASIL et al. 1992 MITTEN et al. 1992 ...
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... Key words: Brassica napus transgenic rape pollen dis-persal isolation distance risk assessment ... 84, 303306. Cresswell, JE, 1994: A method for quantifying the gene fiow that results from a single bumblebee visit using... more
... Key words: Brassica napus transgenic rape pollen dis-persal isolation distance risk assessment ... 84, 303306. Cresswell, JE, 1994: A method for quantifying the gene fiow that results from a single bumblebee visit using transgenic oilseed rape, Brassica napus L. cv. ...
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Fifteen fuzzless seed lines in “obsolete” backgrounds of Upland cotton (Gossypium hirsutum L.) were obtained from the National Cotton Germplasm Collection and evaluated for fuzzless seed genotype, lint percent, and lint quality. Fourteen... more
Fifteen fuzzless seed lines in “obsolete” backgrounds of Upland cotton (Gossypium hirsutum L.) were obtained from the National Cotton Germplasm Collection and evaluated for fuzzless seed genotype, lint percent, and lint quality. Fourteen of these fifteen lines were found to be homozygous for the dominant fuzzless seed allele N 1. Only one line was homozygous for the recessive fuzzless seed allele n 2. The measured lint percent of each line was very stable through time, however, large variability existed between many of the N 1 lines ranging from 0.7 to 23.6% lint. The lint percent for the n 2 line was 24.4%. Scanning electron microscopy was used to differentiate patterns of lint initiation on 1 day post anthesis ovules. General patterns included: first, lint initiation restricted to the chalazal end of the seed crest; second, lint initiation along the seed crest and laterally around the chalazal end of the ovule; and third, lint initiation covered all but the micropylar end of the ovule. Lint quality was evaluated for each line using the Advanced Fiber Information System (AFIS) which included measurements of length, maturity, and fineness. The means of each measurement varied among the fuzzless seed lines with significant differences between fiber length, short fiber content, immature fiber content, fineness, and maturity ratio. No correlation was found between lint percent and any of the lint quality measurements. These lines will provide a valuable resource for the study of fiber initiation and lint quality.