Developmental morphology, biomass yield and compositional differences among upland and lowland switchgrass (Panicum virgatum L.) ecotypes grown as a bioenergy feedstock crop

Sustainable and successful development of the bioenergy industry strongly depends upon the amount and quality of bioenergy feedstock produced. Switchgrass (Panicum virgatum L.) has been identified as a model lignocellulosic bioenergy crop in the U.S. Information regarding its growth and development is considered critical for making management decisions, production of high quality feedstock and to support simulation model calibration and subsequent analysis. In the first study (Chapter 2), we evaluated upland (‘Cave-in-Rock’, ‘Trailblazer’ and ‘Blackwell’) and lowland (‘Kanlow’ and ‘Alamo’) ecotypes of switchgrass for harvest management, morphological (phenology and leaf area index) and biomass yield differences. A field study was conducted near Ames, IA during 2012 and 2013. The experiment was laid out as randomized complete block design. Six in-season destructive biomass harvests were collected at approximately 2-week intervals each year. In both years, delaying harvest to later maturity increased biomass yield in all cultivars. Averaged over years lowland cultivars ‘Kanlow’ and ‘Alamo’ produced higher dry matter yield (6.31 and 5.98 tons ha-1, respectively) than upland ecotypes ‘Cave-in-Rock’, ‘Trailblazer’ and ‘Blackwell’ (5.89, 4.78 and 4.53 tons ha-1, respectively). Lowland cultivars had delayed reproductive development compared with upland ecotypes. The widely recommended cultivar in Iowa ‘Cave-in-Rock’ had the highest mean stage count and leaf area index at the end of both growing seasons, but did not produce the greatest biomass. There was a nonlinear relationship between MSC and biomass yield. However, the magnitude and form of the response was different between cultivars and from year to year. In the next study (Chapter 3), our objective was to quantify the chemical composition of switchgrass varieties as influenced by harvest management, and to determine if ecotypic differences exist among them. We found that delaying harvest increased cellulose, hemicellulose and lignin concentrations while decreasing nitrogen and ash concentrations in all varieties. On average, Kanlow had the highest cellulose and hemicellulose concentration (354 and 321 g kg-1 DM respectively), and Cave-in-Rock had the highest lignin concentration (33 g kg-1 DM). The lowest nitrogen and ash concentrations were observed in Kanlow (14 and 95 g kg-1 DM respectively). In general, our results indicate that delaying harvest until fall improves feedstock quality, and ecotypic differences do exist between varieties for important feedstock quality traits. The objective of the third and final study (Chapter 4), was to developed a new mechanistic model to describe switchgrass phenology with the objective to assist agronomists and on-going breeding programs. Switchgrass is sensitive to photoperiod. However, existing switchgrass phenology models rely on thermal time coupled with ad-hoc empirical modifications to account for the effects of photoperiod when the model is to be applied across a wide range of environments. Our model simulates four phases of switchgrass development (emergence to juvenile, juvenile to elongation, elongation to flowering and flowering to maturity). It uses daily temperature and site latitude as driving variables, contains five cultivar specific biological meaningful parameters, and two model constants (base and optimum temperature of 10 oC and 30 oC, respectively). Three of the cultivar specific parameters (a1, a2, a3) define the thermal optimum time needed to complete a phase and the other two parameters describe the critical photoperiod (pcrit) and the photoperiod sensitivity (psen). The model matched Iowa’s observations with a RMSE (relative mean square error) of 2.6 days for each cultivar or with 5.1 days error when average parameters by ecotype were used. The next step in our analysis was to generalize the model by providing estimates of the photoperiod effect, and for that we used diverse literature database. We found that pcrit was 13.5 h and 12.7 h for upland and lowland cultivars. By using these parameters the overall prediction ability of the model across representative sites in the U.S. had an 8.4 days error. This model can be a helpful tool for improvement and development of calibration protocols for other models and it can also serve as a template for the development of phenology models for other perennial grasse

Developmental Morphology and Biomass Yield of Upland and Lowland Switchgrass Ecotypes Grown in Iowa

Sustainable development of the bioenergy industry will depend upon the amount and quality of bioenergy feedstock produced. Switchgrass (Panicum virgatum L.) is a model lignocellulosic bioenergy crop but critical information is lacking for improved management, growth, and development simulation model calibration. A field study was conducted near Ames, IA during 2012–2013 with the objective to evaluate upland (“Cave-in-Rock”, ‘Trailblazer’ and ‘Blackwell’) and lowland (“Kanlow” and “Alamo”) switchgrass ecotypes for harvest timing on morphology (i.e., phenology, leaf area index (LAI), and biomass yield). The experiment used a randomized complete block design, with three upland and two lowland varieties harvested at six dates annually. In both years, delaying harvest to later maturity increased biomass yield; lowland cultivars produced greater biomass yield (6.15 tons ha−1) than upland ecotypes (5.10 tons ha−1). Lowland ecotypes had delayed reproductive development compared with upland ecotypes. At the end of both growing seasons, upland ecotypes had greater mean stage count (MSC) than lowland ecotypes. “Cave-in-Rock” had greatest MSC and LAI, but did not produce the greatest biomass. Relationships were nonlinear between MSC and biomass yield, with significant cultivar–year interaction. The relationship between biomass yield and MSC will be useful for improving switchgrass, including cultivar selection, fertilizer application, and optimum harvest time

Exploring the better genetic options from indigenous material to cultivate tomato under high temperature regime

Screening test was conducted on 54genotypes of tomato to analyze the effect of heat stress and categorize them as heat tolerant or heat susceptible ones. Seedlings were grown at temperatures of 28/22oC day/night. Four weeks after sowing, plants were exposed to high temperatures of 40/32oC day/night for one week. Data for various morphological (root and shoot length, root and shoot fresh and dry weight, number of leaves) and physiological parameters (chlorophyll contents, sub-stomatal CO2, transpiration rate, stomatal conductance, photosynthetic rate, water use efficiency and leaf temperature) were recorded. Heat stress had a negative effect on all physiological and morphological processes of the genotypes. However, “Parter Improved”, “Legend” and “Roma” were the most tolerant genotypes whereas “Grus Chovka”, “Nepoli”, “Tima France”, “Kaldera” and “Cold Set” were susceptible to heat stress

Extrapulmonary tuberculosis in Pakistan- A nation-wide multicenter retrospective study

Background Pakistan is fifth among high burden countries for tuberculosis. A steady increase is seen in extrapulmonary tuberculosis (EPTB), which now accounts for 20% of all notified TB cases. There is very limited information on the epidemiology of EPTB. This study was performed with the aim to describe the demographic characteristics, clinical manifestations and treatment outcomes of EPTB patients in Pakistan. Method We performed descriptive analysis on routinely collected data for cohorts of TB patients registered nationwide in 2016 at health facilities selected using stratified convenient sampling. Findings Altogether 54092 TB including 15790 (29.2%) EPTB cases were registered in 2016 at 50 study sites. The median age was 24 years for EPTB and 30 years for PTB patients. The crude prevalence of EPTB in females was 30.5% (95%CI; 29.9–31.0) compared to 27.9% (95%CI; 27.3–28.4) in males. The likelihood of having EPTB (OR), was 1.1 times greater for females, 2.0 times for children, and 3.3 times for residents of provinces in the North-West. The most common forms of EPTB were pleural (29.6%), lymphatic (22.7%) and abdominal TB (21.0%). Pleural TB was the most common clinical manifestation in adults (34.2%) and abdominal TB in children (38.4%). An increase in the prevalence of pleural and osteoarticular and decline in lymphatic and abdominal TB was observed with advancing age. Diversity in demography and clinical manifestations were noted between provinces. The treatment success rate for all type EPTB was significantly high compared to bacteriology confirmed PTB with the exception of EPTB affecting CNS with a high mortality rate. Conclusions The study provides an insight into demography, clinical manifestations and treatment outcomes of EPTB. Further studies are needed to explain significant diversities observed between provinces, specific risk factors and challenges concerning EPTB management.publishedVersio

Performance evaluation of nine varieties of Miscanthus in Iowa

Miscanthus is a tall perennial grass species native to parts of Asia. It has the potential to produce relatively high dry matter yields across a wide range of environmental and soil conditions. The Miscanthus cultivar most commonly recommended for biofuel production is a sterile hybrid (M. × giganteus) of M. sacchariflorus × M. sinensis , but there are some challenges for its production. One of them is the occurrence of cold damage during the first winter after planting when plant losses can be high. These losses could be exacerbated by incomplete or late senescence. A field trial was established in spring 2010 with split-plot randomized complete block design with four replicate blocks to evaluate plant senescence timing and rates in nine different varieties of Miscanthus, and to evaluate their morphological characters and yield potential in Iowa. All varieties performed well in both years (2010-2011), with no plant mortalities in any of the variety. Photosynthetic C assimilation (A), stomatal conductance (gs) and total leaf nitrogen (N) concentration ([N]) were measured beginning in late summer and ending at the first hard freeze as indicators of senescence timing and rates. All nine varieties of Miscanthus significantly differed in A, (gs and leaf [N] (P = 0.0001, P = 0.0006, P = 0.0001 respectively). Four out of five Amuri-type varieties responded earlier to environmental signals for autumn and started senescence sooner and at a more rapid pace than the other six varieties of Miscanthus. Varieties also significantly differed for their morphological characters such as plant height (P < 0.0001), tiller density (P < 0.0001), basal circumference (P < 0.0001) and leaf width (P < 0.0001) were observed. Varieties were also significantly different for their above-ground biomass yields (P = 0.01), but no significant differences were observed between varieties for their below-ground biomass yields. In all varieties year had a significant difference (P < 0.0001) for all morphological and yield characters except stem diameter.</p

Developmental morphology, biomass yield and compositional differences among upland and lowland switchgrass (Panicum virgatum L.) ecotypes grown as a bioenergy feedstock crop

Sustainable and successful development of the bioenergy industry strongly depends upon the amount and quality of bioenergy feedstock produced. Switchgrass (Panicum virgatum L.) has been identified as a model lignocellulosic bioenergy crop in the U.S. Information regarding its growth and development is considered critical for making management decisions, production of high quality feedstock and to support simulation model calibration and subsequent analysis. In the first study (Chapter 2), we evaluated upland (‘Cave-in-Rock’, ‘Trailblazer’ and ‘Blackwell’) and lowland (‘Kanlow’ and ‘Alamo’) ecotypes of switchgrass for harvest management, morphological (phenology and leaf area index) and biomass yield differences. A field study was conducted near Ames, IA during 2012 and 2013. The experiment was laid out as randomized complete block design. Six in-season destructive biomass harvests were collected at approximately 2-week intervals each year. In both years, delaying harvest to later maturity increased biomass yield in all cultivars. Averaged over years lowland cultivars ‘Kanlow’ and ‘Alamo’ produced higher dry matter yield (6.31 and 5.98 tons ha-1, respectively) than upland ecotypes ‘Cave-in-Rock’, ‘Trailblazer’ and ‘Blackwell’ (5.89, 4.78 and 4.53 tons ha-1, respectively). Lowland cultivars had delayed reproductive development compared with upland ecotypes. The widely recommended cultivar in Iowa ‘Cave-in-Rock’ had the highest mean stage count and leaf area index at the end of both growing seasons, but did not produce the greatest biomass. There was a nonlinear relationship between MSC and biomass yield. However, the magnitude and form of the response was different between cultivars and from year to year. In the next study (Chapter 3), our objective was to quantify the chemical composition of switchgrass varieties as influenced by harvest management, and to determine if ecotypic differences exist among them. We found that delaying harvest increased cellulose, hemicellulose and lignin concentrations while decreasing nitrogen and ash concentrations in all varieties. On average, Kanlow had the highest cellulose and hemicellulose concentration (354 and 321 g kg-1 DM respectively), and Cave-in-Rock had the highest lignin concentration (33 g kg-1 DM). The lowest nitrogen and ash concentrations were observed in Kanlow (14 and 95 g kg-1 DM respectively). In general, our results indicate that delaying harvest until fall improves feedstock quality, and ecotypic differences do exist between varieties for important feedstock quality traits. The objective of the third and final study (Chapter 4), was to developed a new mechanistic model to describe switchgrass phenology with the objective to assist agronomists and on-going breeding programs. Switchgrass is sensitive to photoperiod. However, existing switchgrass phenology models rely on thermal time coupled with ad-hoc empirical modifications to account for the effects of photoperiod when the model is to be applied across a wide range of environments. Our model simulates four phases of switchgrass development (emergence to juvenile, juvenile to elongation, elongation to flowering and flowering to maturity). It uses daily temperature and site latitude as driving variables, contains five cultivar specific biological meaningful parameters, and two model constants (base and optimum temperature of 10 oC and 30 oC, respectively). Three of the cultivar specific parameters (a1, a2, a3) define the thermal optimum time needed to complete a phase and the other two parameters describe the critical photoperiod (pcrit) and the photoperiod sensitivity (psen). The model matched Iowa’s observations with a RMSE (relative mean square error) of 2.6 days for each cultivar or with 5.1 days error when average parameters by ecotype were used. The next step in our analysis was to generalize the model by providing estimates of the photoperiod effect, and for that we used diverse literature database. We found that pcrit was 13.5 h and 12.7 h for upland and lowland cultivars. By using these parameters the overall prediction ability of the model across representative sites in the U.S. had an 8.4 days error. This model can be a helpful tool for improvement and development of calibration protocols for other models and it can also serve as a template for the development of phenology models for other perennial grasses</p

Performance evaluation of nine varieties of Miscanthus in Iowa

Miscanthus is a tall perennial grass species native to parts of Asia. It has the potential to produce relatively high dry matter yields across a wide range of environmental and soil conditions. The Miscanthus cultivar most commonly recommended for biofuel production is a sterile hybrid (M. × giganteus) of M. sacchariflorus × M. sinensis, but there are some challenges for its production. One of them is the occurrence of cold damage during the first winter after planting when plant losses can be high. These losses could be exacerbated by incomplete or late senescence. A field trial was established in spring 2010 with split-plot randomized complete block design with four replicate blocks to evaluate plant senescence timing and rates in nine different varieties of Miscanthus, and to evaluate their morphological characters and yield potential in Iowa. All varieties performed well in both years (2010–2011), with no plant mortalities in any of the variety. Photosynthetic C assimilation (A), stomatal conductance (gs) and total leaf nitrogen (N) concentration ([N]) were measured beginning in late summer and ending at the first hard freeze as indicators of senescence timing and rates. All nine varieties of Miscanthus significantly differed in A, (gs and leaf [N] (P = 0.0001, P = 0.0006, P = 0.0001 respectively). Four out of five Amuri-type varieties responded earlier to environmental signals for autumn and started senescence sooner and at a more rapid pace than the other six varieties of Miscanthus. Varieties also significantly differed for their morphological characters such as plant height (P < 0.0001), tiller density (P < 0.0001), basal circumference (P < 0.0001) and leaf width (P < 0.0001) were observed. Varieties were also significantly different for their above-ground biomass yields (P = 0.01), but no significant differences were observed between varieties for their below-ground biomass yields. In all varieties year had a significant difference (P < 0.0001) for all morphological and yield characters except stem diameter

Dynamics of Public Debt, Political Institutions, and Economic Growth: A Quantile Analysis in Developing Economies (1996-2021)

This study investigates the interconnected impacts of public debt, political institutional performance, and economic growth in developing nations from 1996 to 2021. By employing the robust quantile via moments methodology, this study effectively addresses the complexities of endogeneity, heterogeneity, and nonlinearity within variables. The outcomes yield significant insights, revealing a consistent negative relationship between public debt and growth in alignment with the "debt overhang" theory. Furthermore, this study identifies a positive link between institutional political performance and political growth. Particularly noteworthy is the finding that the interaction between debt and institutional strength can mitigate the adverse consequences of debt, underscoring the pivotal role of strong institutions. These discoveries underscore the paramount importance of strategic fiscal management and resilient political institutions in nurturing sustainable economic growth. As such, this study holds the potential to guide policy frameworks that amplify the trajectory of developing economies towards enduring economic progress

A Moderating Role of Hierarchy of Institutional Hypothesis in Debt-Poverty Relationship: Empirical Evidence from OIC Member Countries

A plethora of studies deciphered the moderating role of institutional performance in debt-growth and growth-poverty relationship but moderating role of hierarchy of institutional hypothesis in debt-poverty link has not been explored yet. This study is an endeavor to bridge this gap by exploring whether hierarchy of institutional hypothesis moderates the debt-poverty link in the Organization of Islamic Cooperation (OIC) member countries or not during 1996 to 2018. The findings of system GMM estimator disclose that public debt negatively associates with poverty alleviation in OIC member countries. The empirical results backing the notion that the performance of political and economic institutions augment the poverty alleviation. The outcomes also bolster the hypothesis that political institutions are the ones that really modify the course of events. Economic institutions undoubtedly contribute to reducing poverty, but this is only possible in the presence of political institutions. Our study reveals that an average level of political and economic&nbsp;institutional performance lessens the detrimental effects of public debt on poverty alleviation. According to the study's conclusions, the very first Sustainable Development Goal (SDGs), the reduction of poverty by 2030, seems implausible to be achieved given the current tendency of public debt in OIC member countries. In order to reduce the prevalence of poverty in OIC member nations, it is therefore suggested that institutional performance appraisal be linked with a decrease in public debt accumulation. &nbsp