160 research outputs found
Gnuplot scripts for plotting selected leaf gas exchange and morphological data of industrial hemp
No full text<p>Gnuplot code (scripts) for reproducing the seven figures of Sunoj et al. 2024 "Foliar gas exchange, morphology, and cannabinoid profiling of selected varieties of hemp (Cannabis sativa L. ssp. sativa) in southwest Texas," a manuscript to be submitted for peer-review. Here is a list of the authors of the manuscript: John Sunoj V. S. (1), Xuejun Dong (1), Madhumita Joshi (1), Russell W. Jessup (2), Daniel I. Leskovar (1), and David D. Baltensperger (2). Texas A&M AgriLife Research at Uvalde, Texas, USA (1); Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas, USA (2).</p>
Marker-Assisted Verification of Hybrids in Pearl Millet-Napiergrass (Pennisetum glaucum [L.] R. Br. x Pennisetum purpureum Schumach.)
Get PDFMarker-Assisted Verification of Hybrids in Pearl Millet-Napiergrass (Pennisetum glaucum [L.] R. Br. x Pennisetum purpureum Schumach.). (December 2011)
Charlie D. Dowling, III, B.S., College of Agriculture and Life Sciences
Chair of Advisory Committee: Dr. Russell W. Jessup
A high-biomass perennial grass that is directly seeded using existing farm equipment can reduce both planting and overall input costs. Three cytoplasmic male-sterile cms A-lines and four fertile genotypes of pearl millet (Pennisetum glaucum [L.] R. Br.) and one novel pearl millet selection from the Perennial Grass Breeding Program at Texas A&M University were selected to cross with napiergrass (Pennisetum purpureum Schumach.). The pearl millet parents were chosen based on characteristics such as basal tillering, plant height, and days to anthesis. Three napiergrass accessions from the Perennial Grass Breeding Program and the cultivar Merkeron were used as pollinators for these crosses.
The cms and fertile pearl millet accessions produced full heads of seed when pollinated with napiergrass. There were a large range of seed sizes and weights for each hybrid family, and the seed were separated into four size classes. The weight differences from the largest to smallest class of seed varied by more than 30%. All of the seed classes germinated, and seed size, in this case, was completely unrelated to the ability to germinate. 100% germination was observed in five seed size classes for both PMN
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hybrids, and 90% germination was observed in three of the eight classes. Essentially all of the hybrid seed recovered from the original pearl millet x napiergrass crosses germinated, but all of the F
1 hybrids were sterile in that none of them produced viable seed. Flow cytometry could not be used to identify the hybrids because the DNA content of pearl millet and napiergrass were essentially the same even though distinct 2C and 4C peaks were seen from the diploid pearl millet. From the 58 EST-SSRs surveyed in the bulked segregate analysis, several were heterozygous dominant and many were homozygous dominant and hemizygous at its particular loci. Seven hemizygous EST-SSRs were identified for Merkeron, seven for PEPU09FL01, eight for PEPU09FL02, and six for PEPU09FL03. These markers are extremely valuable to any pearl millet x napiergrass hybridization program because they provide a means whereby the hybrids can be easily identified. Identification of hemizygous pearl millet markers will also assist in future DNA sequencing and also in a marker-assisted breeding program
Concepts of suprema and infima, 1973
No full textThe purpose of this thesis is to collect in one place some of the concepts of the supreme and inflma as they apply to different areas of mathematics. My most important sources of information were Advanced Calculus. by Watson Fulks, Real Analysis by H, L, Royden and Real Analysis by Johnston Anderson
Development of Novel Perennial Sorghum Gemplasm: Induced Polyploidization And Hybridization of S. Bicolor X S. Propinquum
Get PDFPlant polyploidization can provide valuable, novel phenotypes. In Sorghum, induced polyploidization is possible and relatively inexpensive. However, efficiency remains low and a consensus ���best��� method has yet to be determined. Some Sorghum species provide a unique opportunity to develop perennial cropping systems due to their interspecific hybridization compatibility and phenotypic plasticity from annual to perennial life cycle. Due to their relatively close taxonomic relationship, Sorghum bicolor (L.) Moench x S. propinquum (Kunth) Hitchc. offer both valuable insights between annuals and perennials, as well as hybridization opportunities for the introgression of perenniality into a major cereal crop. Hybridization between these species also has potential to introgress other desirable alleles that have been lost through the domestication of S. bicolor. Our research identified transgressive segregation for height in a Sorghum bicolor x S. propinquum F2 population. Perennial Sorghum hybrids (PSH) were also intermediate for days to maturity and tillering capacity; when compared to both parents. Experimental units overwintered through harsh winter conditions which allowed a stronger selection criterion for overwintering capacity than previous studies.
Unfortunately, our novel method for inducing ploidy levels in Sorghum were unsuccessful. Thus, more research is still needed to improve this methodology. This thesis addresses induced polyploidy, wide hybridization, and perenniality in the genus Sorghum with the purpose of developing novel germplasm suitable for perennial cropping systems
Carbon, Evapotranspiration and Energy Balance Dynamics of Potential Bioenergy Crops Compared to Cotton in the Southern Great Plains
Get PDFThe Southern Great Plains has potential to produce bioenergy crops on a large scale. However, the potential environmental impact of large scale production of bioenergy crops on carbon, evapotranspiration (ET) and energy dynamics of the region are not understood. This study focuses on land use change associated with bioenergy crops production in the Southern Great Plains and its implication on on-site carbon, energy and ET balances. The carbon and energy balance of two potential bioenergy crops, irrigated sorghum (Sorghum bicolor L.) and dryland old world bluestem (OWB) (Bothriochloa bladhii L.), were assessed and compared with conventional irrigated and dryland cotton (Gossypium hirsutum L.) cropping system of the region. Experiments were conducted on four large producer fields (irrigated sorghum, dryland OWB, irrigated and dryland cotton) in the Texas High plains region. An eddy covariance system was installed in the middle of each field. Continuous measurement of carbon dioxide, latent heat, and sensible heat exchange between plant canopy and atmosphere were made using eddy covariance systems. In addition, net radiation, soil heat flux, air temperature, soil temperature, relative humidity, vapor pressure deficit, soil moisture, photosynthetically active radiation (PAR), and total solar irradiance were measured at each site. Our results showed that mean seasonal net carbon uptake of the sorghum was -615.7 g C m^-2, OWB was -334.9 g C m^-2, irrigated cotton was -136.3 g C m^-2 and dryland cotton was -104.4 g C m^-2. Similarly, mean seasonal ET from sorghum was 480.4 mm, OWB was 384.4 mm, irrigated cotton was 462.9 mm and dryland cotton was 323.2 mm. At an annual scale both sorghum and OWB acted as robust sinks of carbon, whereas cotton cropping systems remained source of carbon. Mean annual net ecosystem exchange of carbon in was -248.1 g C m^-2 in sorghum, -284.9 g C m^-2 in OWB, 112.6 g C m^-2 in irrigated cotton, and 37.2 g C m^-2. At an annual scale irrigated crops recorded higher ET than total annual rainfall. It was also observed that bioenergy crops registered greater ecosystem water use efficiency (3.3 g C kg^-1 H2O in sorghum and 2.8 g C kg^-1 H2O in OWB) than cotton (2.0 g C kg^-1 H2O in irrigated cotton and 1.4 gC kg^-1 H2O in dryland cotton), indicating more sustainability in terms of water usage by bioenergy crops. Among bioenergy crops, sorghum due to irrigation performed better than OWB in terms of carbon assimilation. However, smaller annual ET from OWB than annual rainfall indicated greater groundwater recharge potential. Higher growth rates in C4 bioenergy crops were responsible for their high net carbon sinking capacities. Overall, land use shift from cotton to bioenergy crops was found to be more sustainable in terms of carbon sequestration and water usage
2008 Midwest Levee Failure: Erosion Studies
Get PDFThe United States contains an estimated 100,000 miles (160000 km) of levees in
which erosion related issues are the top priorities. Proper documentation of overtopping
induced erosion is a complicated issue involving the collection and analysis of timesensitive
field data and personal observations. This thesis is a study of the performance
of the Midwest Levee system during the 2008 flooding events.
The goal of the Midwest Levee investigation was to gather and analyze
perishable data in an effort to provide a comprehensive overview at each breach
location. To predict how a site will perform during a particular flood event, there are
three main inputs: the flood conditions, the site conditions, and the soil properties. Site
geometry and imperfections can greatly affect the performance of a levee system. Any
low spots or potential seepage paths can concentrate the flow and be detrimental to the
levee.
The vegetative cover is the single most important condition at a site. As seen in
the Brevator case, vegetative armor can prevent failure of a levee comprised of less
resistant soils subjected to long periods of overtopping. Recommended grasses include:
Switchgrass, Smooth Brome, Reed Canarygrass, and Tall Fescue. It is also recommended that grasses are kept at least 0.5 m tall during the flood season and to limit
the presence of trees to 10 m beyond the levee toe.
The erosion resistance of the materials comprising the levee is also important.
From the correlations in this study, it was determined that erodibility is influenced by
grain size, relative compaction, clay content, and activity. Devices like the Torvane and
Pocket Erodometer can also be used to get a quick field estimate of erosion. While these
correlations and field devices give insight into an erodibility value, they are no substitute
for site specific analysis with laboratory equipment such as the Erosion Function
Apparatus. Soil behavior is highly nonlinear and the entire erosion function is needed to
get an accurate measure of the erodibility of a soil. By combining these properties in an
erosion matrix, a prediction of whether a site will withstand a given flood event can be
made
Evaluation of Herbicides on the Establishment of Pearl Millet [Pennisetum glaucum (L.) R. Br.] x Napiergrass (Pennisetum purpureum Schumach.)
Get PDFPearl millet [Pennisetum glaucum (L.) R. Br.] x napiergrass (Pennisetum purpureum Schumach.) (PMN) hybrids have potential as a seeded, perennial bioenergy or forage crop. The PMN hybrid utilized in this study (PMN10TX13) was developed as an alternative to herbaceous bioenergy feed stocks that either require vegetative propagation, complicated planting strategies due to small seed size, or annual reseeding due to annual growth habit. However, PMN seedlings are impacted by competition from nearby weeds for water, nutrients, and sunlight during establishment. To date, there is limited agronomic information on strategies for effective establishment of weed-free PMN stands. The objective of this study was to develop herbicide response tests to determine the phytotoxic effects of selected pre-crop emergence (PRE) and post-crop emergence herbicides (POST) on the seeded establishment of PMN. Several herbicides with utility for weed free establishment of seeded PMN were successfully identified. Pre-emergent herbicides Balance Pro (isoxaflutole), Dual II (s-metolachlor,) Plateau (imazapic), and Permit (halosulfuron) were effective as long as sufficient rates of seed safener were used. Post-crop emergent herbicides Permit (halosulfuron), Prowl (pendimethalin), Banvel (dicamba), Aatrex (atrazine), AIM (carfentrazone-ethyl), Warrant (achetochlor), and Huskie (pyrasulfotole) were also found to be safe for use at the 5-7 leaf stage and beyond
Phenotypic and Cytological Characterization of Induced Tetraploid, Perennial Sorghum bicolor x S. propinquum Hybrids
Get PDFThe development and use of perennial alternatives to annual crops can help alleviate some of the challenges facing agriculture. Perennial sorghum has the potential of being a low maintenance, drought tolerant, high yielding forage or bioenergy crop.
A novel induced tetraploid (2n=4x=40), interspecific Sorghum bicolor (L.) Moench (annual) x S. propinquum (Kunth) Hitchc. (perennial) hybrid���s progeny was characterized in the F��� and F��� generations.
Field trials were performed to determine their overwintering ability and evaluate various agronomic and morphological traits. The interspecific tetraploid population overwintered well in one evaluation environment (60-85%) and had promising yield potential. Tetraploid entries were intermediate to the parents for most morphological traits. Flowering in the tetraploid was mostly short-day photoperiodic - similar to S. propinquum. Some tetraploid individuals expressed positive transgressive segregation for plant height. Selections can be made for further breeding within the overwintered population based on forage or bioenergy characteristics.
The fertility and cytological behavior of the induced tetraploid S. bicolor x S. propinquum hybrid and its progeny were studied. The meiotic chromosome pairing behavior in these plants was relatively regular with an average of 0.45 univalents, 17.77 bivalents, 0.02 trivalents, and 0.98 quadrivalents per cell. Pollen stainability and seed set were lower than either diploid parent, but sufficiently high that the tetraploid hybrids can be propagated with seed. This germplasm has the potential of being developed into a commercial noninvasive perennial sorghum
EVALUATION OF LEAF PROTEIN CONTENT, EXTRACTION, AND PURIFICATION IN NAPIERGRASS (Pennisetum purpureum SCHUMACH.)
Get PDFAs protein deficiency is still a major health issue in the less developed portion of
the world, novel sources of protein need to be identified. Grasses in the genus
Pennisetum, such as napiergrass, can be a potential alternative protein source. The robust
growth nature of grass provide abundant biomass, as well as enough protein to supply
both livestock and human diets. However, plants are difficult to utilize as protein
sources due to both non-digestible fiber fractions and antiquality factors (phytates,
tannins, etc.). Therefore, feasible approaches are needed to further estimate and purify
the leaf proteins. The objectives of this research are, first, to identify the potential
relationship between leaf proteins and chlorophyll content index (CCI) for developing
indirect tools for leaf protein quantification; and secondly, to further evaluate methods of
leaf protein extraction and purification techniques, including heat coagulation (HC),
mild alkali extraction (AL), and mild alkali extraction with the novel utilization of
activated carbon (ALC). The percentage of crude protein in napiergrass was found to
decrease sequentially at 30, 60, and 90 days of growth in this study. Trends of
decreasing crude protein content between napiergrass parent group and both its selfpollinated
progeny group and its Fv1 hybrid progeny group were also identified. Two
spectroscopic methods were used in this experiment, and both have reported low r^2
values (the highest r^2 = 0.477) for the correlation between crude protein content of
napiergrass and CCI at three harvest dates. Neither heat coagulation nor mild alkali
extraction method improved the extractability of leaf protein. Activated carbon column
treatment effectively removed anti-quality factors (tannins) detected for this experiment.
However, the utilization of activated carbon also caused lower protein yield in the final
purified product
Dalea Aurea, Dalea Candida, Dalea Multiflora and Dalea Purpurea Herbage and Root Nitrogen and Dry Matter Yield as Influenced by Soil, Phosphorus Amendment and Rhizobium Inoculant
Get PDFHerbaceous, perennial, warm-season native North America legumes can contribute to agricultural objectives. Dalea aurea (golden prairie clover), D. multiflora (roundhead prairie clover), D. purpurea (purple prairie clover) and D. candida (white prairie clover) are native to drier prairies and hillsides of Northern Great Plains. Herbage dry matter yield (DMY), root DMY, herbage N DMY, root N DMY and herbage N content were evaluated in Stephenville, TX as a response to soil type, P amendment and Rhizobium inoculation. Dalea aurea yielded 69% more than D. candida, 238% more than D. multiflora and 193% more than D. purpureum, respectively (p���0.05) in herbage DMY. Dalea candida produced 80% greater (p���0.05) root DMY, than D. purpurea which yielded the least. Dalea aurea yielded 108% more than D. candida, 372% more than D. multiflora and 420% more than D. purpurea (p���0.05) herbage N DMY, respectively. Dalea candida yielded 150% more than D. multiflora, 114% more than D. purpurea and 221% more than D. aurea (p���0.05) root N DMY. Dalea aurea had 25% greater (p���0.05) herbage N content than D. multiflora, which yielded the least. Overall, soil types affected herbage and root DMY as well as herbage and root N DMY. Sandy loam was the best for all Dalea species. Inoculation with commercial cowpea rhizobia and amending those soils with P are not recommended without further long-term investigation
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