Botany Commons^™

Accuracy Of Genomic Prediction In Switchgrass (Panicum Virgatum L.) Improved By Accounting For Linkage Disequilibrium, Guillaume P. Ramstein, Joseph Evans, Shawn M. Kaeppler, Robert B. Mitchell, Kenneth P. Vogel, C. Robin Buell, Michael D. Casler

Department of Agronomy and Horticulture: Faculty Publications

Switchgrass is a relatively high-yielding and environmentally sustainable biomass crop, but further genetic gains in biomass yield must be achieved to make it an economically viable bioenergy feedstock. Genomic selection (GS) is an attractive technology to generate rapid genetic gains in switchgrass, and meet the goals of a substantial displacement of petroleum use with biofuels in the near future. In this study, we empirically assessed prediction procedures for genomic selection in two different populations, consisting of 137 and 110 half-sib families of switchgrass, tested in two locations in the United States for three agronomic traits: dry matter yield, plant height, …

Root Biomass And Soil Carbon Response To Growing Perennial Grasses For Bioenergy, Leonard C. Kibet, Humberto Blanco-Canqui, Robert B. Mitchell, Walter H. Schacht

Department of Agronomy and Horticulture: Faculty Publications

Background: Dedicated bioenergy crops such as switchgrass (Panicum virgatum L.), miscanthus [Miscanthus x giganteus (Mxg)], indiangrass [Sorghastrum nutans (L.) Nash], and big bluestem (Andropogon gerardii Vitman) can provide cellulosic feedstock for biofuel production while maintaining or improving soil and environmental quality. To better understand bioenergy crop effects on soils, we studied changes in soil properties of a Tomek silt loam under inorganic fertilization of switchgrass after 4 years and warm-season grass monocultures and mixtures after 6 years in eastern Nebraska.

Methods: The first experiment had two study factors: two switchgrass harvest dates (August and …

Alkaline Stress And Iron Deficiency Regulate Iron Uptake And Riboflavin Synthesis Gene Expression Differently In Root And Leaf Tissue: Implications For Iron Deficiency Chlorosis, En-Jung Hsieh, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Iron (Fe) is an essential mineral that has low solubility in alkaline soils, where its deficiency results in chlorosis. Whether low Fe supply and alkaline pH stress are equivalent is unclear, as they have not been treated as separate variables in molecular physiological studies. Additionally, molecular responses to these stresses have not been studied in leaf and root tissues simultaneously. We tested how plants with the Strategy I Fe uptake system respond to Fe deficiency at mildly acidic and alkaline pH by measuring root ferric chelate reductase (FCR) activity and expression of selected Fe uptake genes and riboflavin synthesis genes. …

Multi-Phase Us Spread And Habitat Switching Of A Post-Columbian Invasive, Sorghum Halepense, U. Uzay Sezen, Jacob N. Barney, Daniel Z. Atwater, Gary A. Pederson, Jeffrey F. Pedersen, J. Mike Chandler, T. Stan Cox, Sheila Cox, Peter Dotray, David Kopec, Steven E. Smith, Jill Schroeder, Steven D. Wright, Yuannian Jiao, Wenqian Kong, Valorie Goff, Susan Auckland, Lisa K. Rainville, Gary J. Pierce, Cornelia Lemke, Rosana Compton, Christine Phillips, Alexandra Kerr, Matthew Mettler, Andrew H. Paterson

Department of Agronomy and Horticulture: Faculty Publications

Johnsongrass (Sorghum halepense) is a striking example of a post-Columbian founder event. This natural experiment within ecological time-scales provides a unique opportunity for understanding patterns of continent-wide genetic diversity following range expansion. Microsatellite markers were used for population genetic analyses including leaf-optimized Neighbor-Joining tree, pairwise FST, mismatch analysis, principle coordinate analysis, Tajima's D, Fu's F and Bayesian clusterings of population structure. Evidence indicates two geographically distant introductions of divergent genotypes, which spread across much of the US ingeophylogeny, gene flow patterns can be inferred to have involved five phases. Centers of genetic diversity have shifted from two introduction …

Genomic Prediction Of Single Crosses In The Early Stages Of A Maize Hybrid Breeding Pipeline, Dnyaneshwar C. Kadam, Sarah M. Potts, Martin O. Bohn, Alexander E. Lipka, Aaron J. Lorenz

Department of Agronomy and Horticulture: Faculty Publications

Prediction of single-cross performance has been a major goal of plant breeders since the beginning of hybrid breeding. Recently, genomic prediction has shown to be a promising approach, but only limited studies have examined the accuracy of predicting single-cross performance. Moreover, no studies have examined the potential of predicting single crosses among random inbreds derived from a series of biparental families, which resembles the structure of germplasm comprising the initial stages of a hybrid maize breeding pipeline. The main objectives of this study were to evaluate the potential of genomic prediction for identifying superior single crosses early in the hybrid …

The Draft Genome Of The C3 Panicoid Grass Species Dichanthelium Oligosanthes, Anthony J. Studer, James C. Schnable, Sarit Weissmann, Allison R. Kolbe, Michael R. Mckain, Ying Shao, Asaph B. Cousins, Elizabeth A. Kellogg, Thomas P. Brutnell

Department of Agronomy and Horticulture: Faculty Publications

Background: Comparisons between C₃ and C₄ grasses often utilize C₃ species from the subfamilies Ehrhartoideae or Pooideae and C₄ species from the subfamily Panicoideae, two clades that diverged over 50 million years ago. The divergence of the C₃ panicoid grass Dichanthelium oligosanthes from the independent C₄ lineages represented by Setaria viridis and Sorghum bicolor occurred approximately 15 million years ago, which is significantly more recent than members of the Bambusoideae, Ehrhartoideae, and Pooideae subfamilies. D. oligosanthes is ideally placed within the panicoid clade for comparative studies of C₃ and C₄ grasses.

Results: …

Estimating Yield Potential In Temperate High-Yielding, Direct-Seeded Us Rice Production Systems, Matthew B. Espe, Haishun Yang, Kenneth Cassman, Nicolas Guilpart, Hussain Sharifi, Bruce A. Linquist

Department of Agronomy and Horticulture: Faculty Publications

Accurate estimation of a crop’s yield potential (Yp) is critical to addressing long-term food security via identification of the exploitable yield gap. Due to lack of field data, efforts to quantify crop yield potential typically rely on crop models. Using the ORYZA rice crop model, we sought to estimate Yp of irrigated rice for two widely used rice varieties (M-206 and CXL745) in three major US rice-producing regions that together represent some of the highest yielding rice regions of the world. Three major issues with the crop model had to be addressed to achieve acceptable simulation of Yp; first, the …

Yield Gap Analysis Of Us Rice Production Systems Shows Opportunities For Improvement, Matthew B. Espe, Kenneth Cassman, Haishun Yang, Nicolas Guilpart, Patricio Grassini, Justin Van Wart, Merle Anders, Donn Beighley, Dustin Harrell, Steve Linscombe, Kent Mckenzie, Randall Mutters, Lloyd T. Wilson, Bruce A. Linquist

Department of Agronomy and Horticulture: Faculty Publications

Many assessments of crop yield gaps based on comparisons to actual yields suggest grain yields in highly intensified agricultural systems are at or near the maximum yield attainable. However, these estimates can be biased in situations where yields are below full yield potential. Rice yields in the US continue to increase annually, suggesting that rice yields are not near the potential. In the interest of directing future efforts towards areas where improvement is most easily achieved, we estimated yield potential and yield gaps in US rice production systems, which are amongst the highest yielding rice systems globally. Zones around fourteen …

Impact Of Derived Global Weather Data On Simulated Crop Yields, Justin Van Wart, Patricio Grassini, Kenneth Cassman

Department of Agronomy and Horticulture: Faculty Publications

Crop simulation models can be used to estimate impact of current and future climates on crop yields and food security, but require long-term historical daily weather data to obtain robust simulations. In many regions where crops are grown, daily weather data are not available. Alternatively, gridded weather databases (GWD) with complete terrestrial coverage are available, typically derived from: (i) global circulation computer models; (ii) interpolated weather station data; or (iii) remotely sensed surface data from satellites. The present study’s objective is to evaluate capacity of GWDs to simulate crop yield potential (Yp) or water-limited yield potential (Yw), which can serve …

Global Nitrogen Budgets In Cereals: A 50-Year Assessment For Maize, Rice, And Wheat Production Systems, J. K. Ladha, A. Tirol-Padre, C. K. Reddy, Kenneth Cassman, Sudhir Verma, D. S. Powlson, C. Van Kessel, Daniel De B. Richter, Debashis Chakraborty, Himanshu Pathak

Department of Agronomy and Horticulture: Faculty Publications

Industrially produced N-fertilizer is essential to the production of cereals that supports current and projected human populations. We constructed a top-down global N budget for maize, rice, and wheat for a 50-year period (1961 to 2010). Cereals harvested a total of 1551 Tg of N, of which 48% was supplied through fertilizer-N and 4% came from net soil depletion. An estimated 48% (737 Tg) of crop N, equal to 29, 38, and 25 kg ha⁻¹ yr⁻¹ for maize, rice, and wheat, respectively, is contributed by sources other than fertilizer- or soil-N. Non-symbiotic N₂ fixation appears to be …

Smokey Comes Of Age: Unmanned Aerial Systems For Fire Management, Dirac L. Twidwell Jr., Craig R. Allen, Carrick Detweiler, James Higgins, Christian Laney, Sebastian Elbaum

Department of Agronomy and Horticulture: Faculty Publications

During the past century, fire management has focused on techniques both to protect human communities from catastrophic wildfire and to maintain fire-dependent ecological systems. However, despite a large and increasing allocation of resources and personnel to achieve these goals, fire management objectives at regional to global scales are not being met. Current fire management techniques are clearly inadequate for the challenges faced by fire managers, and technological innovations are needed. Advances in unmanned aerial systems (UAS) technology provide opportunities for innovation in fire management and science. In many countries, fire management organizations are beginning to explore the potential of UAS …

Identification Of Markers Linked To Genes For Sprouting Tolerance (Independent Of Grain Color) In Hard White Winter Wheat (Hwww), Juthamas Fakthongphan, Guihua Bai, Paul St. Amand, Robert A. Graybosch, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Key message Hard red wheats can donate genes to hard white wheats for tolerance to preharvest sprouting, the effects are quantitative in nature, and may be tracked with previously described DNA markers.

Abstract Pre-harvest sprouting (PHS) of wheat (Triticum aestivum L.) can negatively impact end-use quality and seed viability at planting. Due to preferences for white over red wheat in international markets, white wheat with PHS tolerance has become increasingly desired for worldwide wheat production. In general, however, red wheat is more tolerant of sprouting than white wheat. The main objective of this study was the identification of PHS …

Soil Water Improvements With The Long-Term Use Of A Winter Rye Covercrop, Andrea D. Basche, Thomas C. Kaspar, Sotirios V. Archontoulis, Dan B. Jaynes, Thomas J. Sauer, Timothy B. Parkin, Fernando E. Miguez

Department of Agronomy and Horticulture: Faculty Publications

The Midwestern United States, a region that produces one-third of maize and one-quarter of soybean grain globally, is projected to experience increasing rainfall variability. One approach to mitigate climate impacts is to utilize crop and soil management practices that enhance soil water storage and reduce the risks of flooding as well as drought-induced crop water stress. While some research indicates that a winter cover crop in maize-soybean rotations increases soil water availability, producers continue to be concerned that water use by cover crops will reduce water for a following cash crop. We analyzed continuous in-field soil water measurements from 2008 …

Engaging Middle School Students Through Locally Focused Environmental Science Project-Based Learning, Andrea D. Basche, Vincent Genareo, Adah Leshem, Amy Kissell, Judith Pauley

Department of Agronomy and Horticulture: Faculty Publications

Increasing scientific literacy through education is one way to promote awareness of current environmental challenges, and can be enhanced through project-based learning (PBL), a pedagogical approach in which students explore authentic topics and demonstrate their learning publically. The National Science Foundation–funded GK–12 program at Iowa State University partnered doctoral-level graduate students (fellows) with middle and high school science teachers. This study analyzed results from one such middle school partnership in Iowa, where a PBL approach was implemented. Classroom practices focused on local environmental case studies of energy development, water pollution, soil science, climate change, plant biology, and ecology. Results from …

Impact Of Pre-Anthesis Water Deficit On Yield And Yield Components In Barley (Hordeum Vulgare L.) Plants Grown Under Controlled Conditions, Zakaria I. Al-Ajlouni, Ayed Al-Abdallat, Abdul Latief A. Al-Ghzawi, Jamal Y. Ayad, Jamal M. Abu Elenein, Nisreen A. Al-Quraan, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Drought at pre-anthesis stages can influence barley growth and results in yield losses. Therefore, it is important to understand how drought at pre-anthesis can affect different traits associated with yield reduction in barley. The objective of this study was to understand the relevance of the genetic background of major flowering time genes in barley plants subjected to pre-anthesis drought and its impact on yield and yield components. A glasshouse experiment using a Randomized Complete Block Design was conducted to investigate the effect of drought and its timing on yield and yield components on eleven barley genotypes, which were selected to …

Predicting Long-Term Cover Crop Impacts On Soil Quality Using A Cropping Systems Model, Fernando E. Miguez, Sotirios Archontoulis, Andrea D. Basche

Department of Agronomy and Horticulture: Faculty Publications

Increased attention is being paid to cover crops as an option to reduce water pollution and decrease soil degradation in Iowa. More producers are experimenting with cover crops to increase soil productivity. However, when this project began there was little research to demonstrate the long-term impacts that cover crops have on crop yields. There were no estimates to quantify how much environmental benefit a cover crop could provide in terms of erosion and soil carbon changes. Such estimates are beneficial to demonstrate the long-term improvements that a cover crop affords in Iowa, particularly for corn-soybean rotations where the winter planting …

Corn Response To Nitrogen Management Under Fully-Irrigated Vs. Water-Stressed Conditions, Bijesh Maharjan, Carl J. Rosen, John A. Lamb, Rodney T. Venterea

Department of Agronomy and Horticulture: Faculty Publications

Characterizing corn (Zea mays L.) grain yield (GY) response to N is critical for maximizing profits, increasing N use efficiency and minimizing environmental impacts. Although a large database of GY response to N exists for highly productive soils, few data exist for less productive soils. While changes in precipitation are expected in the future, few studies have compared GY response to varying N management practices under conditions of varying water availability. We measured GY and basal stalk nitrate nitrogen (BSN) at harvest using split-applied urea at eight N rates under fully-irrigated (FI) and water-stressed (WS) conditions in a loamy …

Identification Of Evening Complex Associated Proteins In Arabidopsis By Affinity Purification And Mass Spectrometry, He Huang, Sophie Alvarez, Rebecca Bindbeutel, Zhouxin Shen, Michael J. Naldrett, Bradley S. Evans, Steven P. Briggs, Leslie M. Hicks, Steve A. Kay, Dmitri A. Nusinow

Department of Agronomy and Horticulture: Faculty Publications

Many species possess an endogenous circadian clock to synchronize internal physiology with an oscillating external environment. In plants, the circadian clock coordinates growth, metabolism and development over daily and seasonal time scales. Many proteins in the circadian network form oscillating complexes that temporally regulate myriad processes, including signal transduction, transcription, protein degradation and post-translational modification. In Arabidopsis thaliana, a tripartite complex composed of EARLY FLOWERING 4 (ELF4), EARLY FLOWERING 3 (ELF3), and LUX ARRHYTHMO (LUX), named the evening complex, modulates daily rhythms in gene expression and growth through transcriptional regulation. However, little is known about the physical interactions that …

Multidisciplinary Research And Extension Team Evolution: Processes, Outcomes, And Strategies, Daren Redfearn, Jay Parsons, Mary Drewnoski

Department of Agronomy and Horticulture: Faculty Publications

Team-based research is not an innovative concept; however, the current models of team research are based principally on self-formed teams with a defined duration. Current trends seem to point toward the development of administratively designed multidisciplinary teams. Although this seems logical, minimal guidelines exist to aid in team development or evaluate team outcomes. Critical processes in a team-based research atmosphere have not been identified, much less described, and strategies for successful implementation have not been proposed. The strength of this approach can be summarized as a unified focus during the course of problem definition and solution. Many trade-offs and obstacles …

Identification And Verification Of Qtl Associated With Frost Tolerance Using Linkage Mapping And Gwas In Winter Faba Bean, Ahmed Sallam, Mustapha Arbaoui, Mohamed El-Esawi, Nathan Abshire

Department of Agronomy and Horticulture: Faculty Publications

Frost stress is one of the abiotic stresses that causes a significant reduction in winter faba bean yield in Europe. The main objective of this work is to genetically improve frost tolerance in winter faba bean by identifying and validating QTL associated with frost tolerance to be used in marker-assisted selection (MAS). Two different genetic backgrounds were used: a biparental population (BPP) consisting of 101 inbred lines, and 189 genotypes from single seed descent (SSD) from the Gottingen Winter bean Population (GWBP). All experiments were conducted in a frost growth chamber under controlled conditions. Both populations were genotyped using the …

Modeling Shattercane Dynamics In Herbicide-Tolerant Grain Sorghum Cropping Systems, Rodrigo Werle, Brigitte Tenhumberg, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Traditional breeding technology is currently being used to develop grain sorghum [Sorghum bicolor (L.) Moench ssp. bicolor] germplasm that will be tolerant to acetolactate synthase (ALS)-inhibiting herbicides. This technology (Inzen^TM, DuPont^TM) has the potential to improve sorghum production by allowing for the postemergence control of traditionally hard-to-control grasses. However, grain sorghum and shattercane [weedy Sorghum species; Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet ex Davidse] can interbreed and introduced traits such as herbicide tolerance could increase the weediness of the weedy relative. Our objective was to develop a simulation model …

Letter To The Editor Ws-2 Introgression In A Proportion Of Arabidopsis Thaliana Col-0 Stock Seed Produces Specific Phenotypes And Highlights The Importance Of Routine Genetic Verification, Mon-Ray Shao, Vikas Shedge, Hardik Kundariya, Fredric R. Lehle, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Arabidopsis thaliana is an important model organism with a robust network of resources that has been of enormous value to the plant science research community. The use of isogenic material as a reference point or control is critical for many types of experiments in plant molecular biology and genetics. Recently, we noticed that some seed from a common source of the widely-used Columbia-0 (Col-0) strain gave rise to plants showing features atypical for this strain. Whole genome DNA-sequencing and allele-specific PCR assays confirmed that the abnormal individuals contain multiple introgressions from the ecotype Wassilewskija-2 (Ws-2), as described below. This emphasizes …

Transcriptome Profiling Of Kentucky Bluegrass (Poa Pratensis L.) Accessions In Response To Salt Stress, Shaun B. Bushman, Keenan L. Amundsen, Scott E. Warnke, Joseph G. Robins, Paul G. Johnson

Department of Agronomy and Horticulture: Faculty Publications

Background: Kentucky bluegrass (Poa pratensis L.) is a prominent turfgrass in the cool-season regions, but it is sensitive to salt stress. Previously, a relatively salt tolerant Kentucky bluegrass accession was identified that maintained green color under consistent salt applications. In this study, a transcriptome study between the tolerant (PI 372742) accession and a salt susceptible (PI 368233) accession was conducted, under control and salt treatments, and in shoot and root tissues.

Results: Sample replicates grouped tightly by tissue and treatment, and fewer differentially expressed transcripts were detected in the tolerant PI 372742 samples compared to the susceptible …

Extension Agriculture And Natural Resources In The U.S. Midwest: A Review And Analysis Of Challenges And Future Opportunities, Mahdi M. Al-Kaisi, Roger Wesley Elmore, Gerald A. Miller, David Kwaw-Mensah

Department of Agronomy and Horticulture: Faculty Publications

This review addresses key changes in U.S. agricultural extension and future opportunities. Agricultural extension has been a part of the land-grant university (LGU) system for more than 100 years. The Morrill Act of 1862 established the LGU system by authorizing states access to federally controlled land and funding for public institutions offering educational opportunities focusing on agriculture and mechanical arts for farmers and the working class. Current surveys in Iowa reveal changing trends in extension: more than 90% of farmers identified private-sector crop advisers as their primary source for recommendations, whereas more than 80% of those advisors identified Iowa State …

Soybean Yield And Nodulation Response To Crop History And Inoculation, Stephen Mason, Tomie Galusha, Zaher Kmail

Department of Agronomy and Horticulture: Faculty Publications

Soybean [Glycine max (L.) Merr.] inoculation was imposed on a long-term continuous grain sorghum [Sorghum bicolor (L.) Moench] and soybean cropping systems study with and without manure application at Mead, NE. The objective was to determine the influence of 28-yr history of continuous grain sorghum and soybean production, inoculation, and manure on soybean yield and nodulation. Average 2-yr soybean grain yield was 0.5 Mg ha^–1 greater on plots with continuous grain sorghum crop history rather than soybean history, even after this history was broken by 2-yr crop rotation with grain sorghum in the 2 yr previous to …

Soil Moisture Affects Growing-Season Wildfire Size In The Southern Great Plains, Erik S. Krueger, Tyson E. Ochsner, David M. Engle, J. D. Carlson, Dirac L. Twidwell, Samuel D. Fuhlendorf

Department of Agronomy and Horticulture: Faculty Publications

The increasing availability of soil moisture data presents an opportunity for its use in wildfire danger assessments, but research regarding the influence of soil moisture on wildfires is scarce. Our objective was to identify relationships between soil moisture and wildfire size for Oklahoma wildfires during the growing (May-October) and dormant seasons (November-April). We hypothesized that soil moisture influences wildfire size when vegetation is growing but is less important when most vegetation is dead or dormant. Soil moisture, as fraction of available water capacity (FAW), and commonly measured weather variables were determined for 38,419 wildfires from 2000–2012. Wildfires were grouped by …

Book Reviews: Bumble Bees Of North America. Paul H. Williams, Robbin W. Thorp, Leif L. Richardson, And Sheila R. Colla., Samuel O’Dell

The Prairie Naturalist

Bumblebee identification is generally considered straight- forward, yet mistakes often are made due to the degree of similarity between the color patterns of different species. Bumble Bees of North America aims to improve the accuracy of identifications by both casual observers and professionals through the use of intuitive diagrams, descriptions, and the more technical dichotomous keys. In addition to providing the first complete field guide to North American bumblebees, the authors make efficient use of the reader’s attention by summarizing taxonomic history, favored food plants, and environmental issues concerning bumblebees.

Bumble Bees of North America is organized into three distinct …

Effects Of Short-Term Soil Conditioning By Cheatgrass And Western Wheatgrass, James J. O'Connor, Janet S. Prevey

The Prairie Naturalist

The exotic grass Bromus tectorum (cheatgrass) is a ubiquitous invader in the western USA. Cheatgrass is a proficient competitor, frequently displacing native plants, forming monotypic stands and reducing biodiversity in ecosystems it invades. Our experiment tested whether short-term soil modification by cheatgrass and a predominant native grass, Pascopyrum smithii (western wheatgrass), affected subsequent growth of both species. We compared productivity of cheatgrass and western wheatgrass by harvesting aboveground biomass of plants grown in either cheatgrass- or western wheatgrass-conditioned soils over two simulated growing seasons. Results indicated that cheatgrass soils do not inhibit the productivity of the native grass, but do …

North Shore: A Natural History Of Minnesota’S Superior Coast, Janet R. Koeugh

The Prairie Naturalist

Many readers of The Prairie Naturalist have lived along or visited Lake Superior’s coast. Like me, you have probably wondered about the geology and history of this beautiful and dramatic feature of northeastern Minnesota. Chel Anderson and Adelheid Fischer have written an accessible book that comprehensively describes the history and geology of the coast, surrounding highlands, and Lake Superior itself. In addition, the authors have provided fascinating subchapters on some of the most interesting species that are key elements of the region.

This rather large but beautiful book is arranged in five major chapters that cover the dominant geological units …

Remembering Paul B. Kannowski, Robert Seabloom

The Prairie Naturalist

I am saddened to report that Dr. Paul Kannowski passed away 3 September 2015, succumbing to cancer. He was 88. A native of Grand Forks, Paul attended the University of North Dakota for his B.S. and M.S. degrees, and the University of Michigan for his Ph.D. He joined the University of North Dakota Biology Department in 1957, retiring in 1990 after 33 years of service

Paul chaired UND’s Biology Department twice, totaling 13 years, considered to be a remarkable achievement by many of us who have been exposed to that task! His leadership was instrumental in the nearly exponential growth …