Plant Biology Commons^™

Adjusting Corn Nitrogen Management By Including A Mineralizable-Nitrogen Test With The Preplant And Presidedress Nitrate Tests, Jason Clark, Fabián G. Fernández, Kristen S. Veum, James J. Camberato, Paul R. Carter, Richard Ferguson, David W. Franzen, Daniel E. Kaiser, Newell R. Kitchen, C. A.M. Laboski, Emerson Nafziger, Carl J. Rosen, John E. Sawyer, John F. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

The anaerobic potentially mineralizable N (PMN) test combined with the preplant (PPNT) and presidedress (PSNT) nitrate tests may improve corn (Zea mays L.) N fertilization predictions. Forty-nine corn N response experiments (mostly corn following soybean [Glycine max (L.) Merr.]) were conducted in the U.S. Midwest from 2014–2016 to evaluate the ability of the PPNT and PSNT to predict corn relative yield (RY) and N fertilizer over- and under-application rates when adjusted by PMN. Before planting and N fertilization, PPNT (0–30, 30–60, and 60–90 cm) and PMN (0–30 cm) samples were obtained. In-season soil samples were obtained at the …

Relating Four-Day Soil Respiration To Corn Nitrogen Fertilizer Needs Across 49 U.S. Midwest Fields, G. M. Bean, Newell R. Kitchen, Kristen S. Veum, James J. Camberato, Richard Ferguson, Fabian G. Fernandez, David W. Franzen, Carrie A.M. Laboski, Emerson Nafziger, John E. Sawyer, Matt Yost

Department of Agronomy and Horticulture: Faculty Publications

Soil microbes drive biological functions thatmediate chemical and physical processes necessary for plants to sustain growth. Laboratory soil respiration has been proposed as one universal soil health indicator representing these functions, potentially informing crop and soil management decisions. Research is needed to test the premise that soil respiration is helpful for profitable in-season nitrogen (N) rate management decisions in corn (Zea mays L.). The objective of this research was two-fold: (i) determine if the amount of N applied at the time of planting effected soil respiration, and (ii) evaluate the relationship of soil respiration to corn yield response to …

Adding A Late Fall Application Of Proxy (Ethephon) Before Two Traditional Spring Applications Improves Seedhead Control Of Annual Bluegrass, Zachary Reicher, Matthew Sousek, Aaron J. Patton, Adam Van Dyke, William C. Kreuser, John C. Inguagiato, Kevin M. Miele, John Brewer, Shawn D. Askew, Aaron Hathaway, Thomas A. Nikolai, Alec Kowalewski, Brian Mcdonald

Department of Agronomy and Horticulture: Faculty Publications

Annual bluegrass (ABG) (Poa annua L.) is a prolific seed producer in the spring on golf courses that in turn decreases aesthetic quality and trueness of ball roll on coolseason putting greens. Proxy (ethephon) applied twice in the spring after green-up is the current industry standard after the loss of Embark (mefluidide) from the turf and ornamental market. However, plant growth regulators including Proxy have been used for years to help suppressABGseedheads with inconsistent success. The primary objective of this study was to determine if ABG seedhead suppression is improved by adding a late fall application of Proxy to …

Allelic Variation In Rice Fertilization Independent Endosperm 1 Contributes To Grain Width Under High Night Temperature Stress, Balpreet K. Dhatt, Puneet Paul, Jaspreet Sandhu, Waseem Hussain, Larissa Irvin, Feiyu Zhu, Maria Arlene Adviento-Borbe, Argelia Lorence, Paul Staswick, Hongfeng Yu, Gota Morota, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

A higher minimum (night-time) temperature is considered a greater limiting factor for reduced rice yield than a similar increase in maximum (daytime) temperature. While the physiological impact of high night temperature (HNT) has been studied, the genetic and molecular basis of HNT stress response remains unexplored.

We examined the phenotypic variation for mature grain size (length and width) in a diverse set of rice accessions under HNT stress. Genome-wide association analysis identified several HNT-specific loci regulating grain size as well as loci that are common for optimal and HNT stress conditions.

A novel locus contributing to grain width under HNT …

Leveraging Genome-Enabled Growth Models To Study Shoot Growth Responses To Water Deficit In Rice, Malachy T. Campbell, Alexandre Grondin, Harkamal Walia, Gota Morota

Department of Agronomy and Horticulture: Faculty Publications

lucidating genotype-by-environment interactions and partitioning its contribution to phenotypic variation remains a challenge for plant scientists. We propose a framework that utilizes genome-wide markers to model genotype-specific shoot growth trajectories as a function of time and soil water availability. A rice diversity panel was phenotyped daily for 21 d using an automated, high-throughput image-based, phenotyping platform that enabled estimation of daily shoot biomass and soil water content. Using these data, we modeled shoot growth as a function of time and soil water content, and were able to determine the time point where an inflection in the growth trajectory occurred. We …

Voxel Carving-Based 3d Reconstruction Of Sorghum Identifies Genetic Determinants Of Light Interception Efficiency, Mathieu Gaillard, Chenyong Miao, James Schnable, Bedrich Benes

Department of Agronomy and Horticulture: Faculty Publications

Changes in canopy architecture traits have been shown to contribute to yield increases. Optimizing both light interception and light interception efficiency of agricultural crop canopies will be essential to meeting the growing food needs. Canopy architecture is inherently three-dimensional (3D), but many approaches to measuring canopy architecture component traits treat the canopy as a two-dimensional (2D) structure to make large scale measurement, selective breeding, and gene identification logistically feasible. We develop a high throughput voxel carving strategy to reconstruct 3D representations of sorghum from a small number of RGB photos. Our approach builds on the voxel carving algorithm to allow …

Genome-Wide Identification And Analysis Of Heterotic Loci In Three Maize Hybrids, Hongjun Liu, Qin Wang, Mengjiao Chen, Yahui Ding, Xuerong Yang, Jie Liu, Xiaohan Li, Congcong Zhou, Qilin Tian, Yiqi Lu, Danlin Fan, Junpeng Shi, Lin Zhang, Congbin Kang, Mingfei Mingfei Sun, Fangyuan Li, Yujian Wu, Yongzhong Zhang, Baoshen Liu, Xiang Yu Zhao, Qi Feng, Jinliang Yang, Bin Han, Jinsheng Lai, Xian Sheng Zhang, Xuehui Huang

Department of Agronomy and Horticulture: Faculty Publications

Heterosis, or hybrid vigour, is a predominant phenomenon in plant genetics, serving as the basis of crop hybrid breeding, but the causative loci and genes underlying heterosis remain unclear in many crops. Here, we present a large-scale genetic analysis using 5360 offsprings from three elite maize hybrids, which identifies 628 loci underlying 19 yield-related traits with relatively high mapping resolutions. Heterotic pattern investigations of the 628 loci show that numerous loci, mostly with complete–incomplete dominance (the major one) or overdominance effects (the secondary one) for heterozygous genotypes and nearly equal proportion of advantageous alleles from both parental lines, are the …

The Balancing Act Of Cytokinin In Environmental Stress Tolerance, Sumudu Sandeepani Karunadasa

Theses and Dissertations--Plant and Soil Sciences

Cytokinin, long known as a phytohormone that regulates plant growth and development, has been recently recognized as an important regulator of stress responses. However, our current knowledge about the mechanisms by which cytokinin regulates stress responses is fragmentary, as many of the studies in this field yielded conflicting results. Most of the work described here has focused on analyses of the molecular mechanisms of cytokinin-dependent regulation of growth and development under stress conditions, with an emphasis on the role of cytokinin-dependent regulation of protein synthesis in development and stress tolerance.

One of the important contributions of this study is the …

Stimulated Growth Response To Sand Burial Of A Coastal Shrub, D. Nicole Keller

Theses and Dissertations

Drivers of vegetation zonation on barrier islands are complex and interconnected. Sand burial is a strong driver in dynamic coastal systems, especially in the foredune community. However, it is not well understood how burial impacts the interdunal swales communities and it is especially difficult to separate the effects of burial from salinity. Climate change is altering the frequency of overwash events as well as expanding the range of the native shrub, Morella cerifera, on the Virginia barrier islands. To accurately forecast island response to climate change it is important to understand how the shrub responds to sand burial. Juvenile …

The Effects Of Woody Vegetation Encroachment And Removal Within A Coastal Fen, Joseph Saler

Cal Poly Humboldt theses and projects

Early successional wetland habitat is being lost in temperate regions worldwide as a result of changes in disturbance regimes that allow for the establishment and dominance of woody species. In particular, this phenomenon is pronounced in fens, which harbor high numbers of rare herbaceous species that require early successional habitat. I investigated the relationship between woody vegetation encroachment and herbaceous species diversity within a Northern California coastal fen that has been undergoing encroachment by woody vegetation for ca. 80 years by recording species richness and cover data from 338 permanent plots throughout the fen. I also investigated the effect of …

The Morphological, Physiological, And Genetic Underpinnings Of Intraspecific Salinity Tolerance In Sorghum Bicolor, Ashley N. Henderson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Decreases in land quality and quantity threaten the efficient production of agriculturally and economically pivotal crops. Such reductions in arable lands are a consequence of population growth and urbanization, and often result in the introduction of various abiotic stresses. The most common abiotic stressors include water limitation (drought), water logging (over watering), poor water quality (salinity), and extreme temperatures (cold, frost, heat). Each of these stressors negatively impact plant growth, development, and yield. Soil salinity, specifically, is a considerable constraint affecting lands used in agriculture. Salts in the soil rise both naturally and through anthropogenic factors making the abundance a …

Phenology Of Cupressaceae Urban Infrastructure Related To Its Pollen Content And Meteorological Variables, A. Monroy-Colín, J. M. Maya-Manzano, I. Silva-Palacios, R. Tormo-Molina, R. Pecero-Casimiro, Á. Gonzalo-Garijo, S. Fernández-Rodríguez

Articles

Cupressaceae pollen is one of the major airborne allergens of the Mediterranean region and in other regions around the world. Pollen production of these species causes considerable allergic problems during winter, being this type of pollen the most abundant in this period of the year. This work aims to relate phenology, meteorology and airborne pollen records in these species. Aerobiological sampling was carried out in Badajoz (SW Spain) from 2016 to 2018 using Hirst-type volumetric sampler. Pollination phenology was studied in 50 specimens, ten of Cupressus macrocarpa, ten of Cupressus arizonica, 15 of Cupressus sempervirens and 15 of …

The Development Of Crassulacean Acid Metabolism (Cam) Photosynthesis In Cotyledons Of The C4 Species, Portulaca Grandiflora (Portulacaceae), Lonnie J. Guralnick, Kate E. Gilbert, Diana Denio, Nicholas Antico

Arts & Sciences Faculty Publications

Portulaca grandiflora simultaneously utilizes both the C₄ and Crassulacean acid metabolism (CAM) photosynthetic pathways. Our goal was to determine whether CAM developed and was functional simultaneously with the C₄ pathway in cotyledons of P. grandiflora. We studied during development whether CAM would be induced with water stress by monitoring the enzyme activity, leaf structure, JO₂ (rate of O₂ evolution calculated by fluorescence analysis), and the changes in titratable acidity of 10 and 25 days old cotyledons. In the 10 days old cotyledons, C₄ and CAM anatomy were evident within the leaf tissue. The cotyledons showed …

Can Precision Farming Technologies Be Applied To Grazing Management?, S. Mark Rutter

IGC Proceedings (1977-2023)

In arable farming, precision is used to monitor and manage crop variability. The same precision approach can be used to manage grassland, by using crop sensing, targeted fertilizer/herbicide/pesticide application and forage yield measurement when it is harvested mechanically. An additional challenge in grassland agriculture is developing precision approaches to manage the grazing process. This requires technologies to determine where an animal is, when, what and how much it is grazing which the system then needs to use in conjunction with other sources of information to control where the animal grazes next. This paper reviews the existing technologies in these …

Manipulation Of The Spatial Grazing Behaviour Of Livestock In Extensive Grassland Systems, Derek W. Bailey, Mitch B. Stephenson, Milton G. Thomas, Juan F. Medrano, Gonzalo Rincon

IGC Proceedings (1977-2023)

Spatial behaviour of livestock is a critical factor in grassland management. Recent and ongoing research suggests that new approaches can be used to manipulate where cattle graze. The combination of strategic supplement placement and low-stress herding can be used to target cattle grazing and potentially may be useful for managing fine fuels. A phenotype to genotype association study of cattle spatial behavior suggests that use of rugged terrain and areas far from water is inherited. Although more research is needed, selection for animals specifically adapted for mountainous terrain or extensive paddocks may be an alternative for managing grasslands in the …

Case Studies Which Demonstrate The Financial Viability Of Precision Dairy Farming, Ian Yule, Hayden Lawrence, Craige Mackenzie, Carolyn Hedley, Miles Grafton

IGC Proceedings (1977-2023)

A number of case studies are used to demonstrate the financial viability of precision farming methods for intensively managed pastures. Precision farming has sometimes been criticized as being technology-led where the management goals and desired outcomes are sometimes poorly defined. Case studies presented in this paper demonstrate a strong management approach where appropriate technologies are selected to contribute to the financial success of the farm. The first case study farm has increased milk production by 70% in four years, increased pasture production by 43%, reduced fertilizer costs to 43% of previous levels and has successfully predicted annual production to within …

Do Coffee Agroforestry Systems Always Improve Soil Carbon Stocks Deeper In The Soil?—A Case Study From Turrialba, Costa Rica, Nilovna Chatterjee, P. K. Ramachandran Nair, Vimala D. Nair, Abhishek Bhattacharjee, Elias De Melo Virginio Filho, Rheinhold G. Muschler, Martin R.A. Noponen

Department of Agronomy and Horticulture: Faculty Publications

Shaded perennial agroforestry systems (AFS) are regarded as desirable land‐use practices that improve soil carbon sequestration. However, most studies assume a positive correlation between above ground and below ground carbon without considering the effect of past and current land management, textural variations (silt and clay percentage), and such other site‐specific factors that have a major influence on the extent of soil C sequestration. We assessed SOC stock at various depths (0–10, 10–30, 30–60, and 60–100 cm) in shaded perennial coffee (Coffea arabica L.) AFS in a 17‐ year‐old experimental field at the Centro Agronómico Tropical de Investigación y Enseñanza, (9°53′44′′ …

Altitudinal Distribution And Monthly Occurrence Of Butterflies In The Kihansi Gorge Forest, Tanzania, With A Checklist Of Species, Devolent Mtui, Colin Congdon, Ivan Bampton, Parson Kalenga, Haule Leonard

Tanzania Journal of Science

The goal of this project was to establish a checklist of butterflies occurring in Kihansi gorge to serve as baseline for monitoring of gorge ecosystem health. The key questions were what and how many species of butterflies occur in the gorge with respect to time and space. The study was conducted between October 2005 and February 2007. Butterflies were recorded twice a week, along a walking trail, using malaise traps and sweep net. The traps were located at upper (> 750 – 1100 m), mid (> 580 – 750 m) and lower (300 – 580 m) gorge. A total of …

Crop Pests, Control Measures And Potential Impacts In Kihansi Catchment Area, Beatrice Pallangyo, K. Mdily, C. Mkondo, A. Kibola

Tanzania Journal of Science

A baseline survey which covered 349 households in Bomang’ombe and Masisiwe (Kilolo district), Kibengu and Mapanda (Mufindi district) and Chita and Chisano (Kilombero district) was conducted to identify major pests, control measures and potential impacts in Kihansi catchment area. Maize was the most predominant crop being cultivated by 55% of the total respondents in all the study districts. Pests and diseases were the major constraints to crop production, whereby cereal stem borers were the most serious pests being reported by 88.2% of respondents. Application of synthetic pesticides was the major pest control measure, being applied by 66% of the respondents. …

Morphological Diversity Of Wild Coffee (Coffea Kihansiensis) A Potential Coffee Species For Genetic Improvement, Paul M Kusolwa, Faraja Makwinja, Jackson Nashon, Mayomba Marianna, Amina Kibola

Tanzania Journal of Science

Coffee belongs to the genus Coffea in the Rubiaceae family, and is mostly grown in the tropical and subtropical regions. The Coffea genus comprises 103 species, of which Coffea arabica L. (Arabica coffee) and Coffea canephora P. (Robusta coffee) are the two most important commercial species. C. Arabica is a commercially important high quality coffee with low genetic diversity, while C. canephora is cultivated mostly in the northwestern region of Tanzania. Of recent, a discovered wild coffee (Coffea kihansiensis) in Tanzania may be a genetic resource for improvement of cultivated coffee.  Morphological descriptors from accessions evaluated in different sites at …