Other Plant Sciences Commons^™

Fungicide Application Timing And Disease Control, Tamra A. Jackson-Ziems, Loren J. Giesler, Robert M. Harveson, Stephen N. Wegulo, Kevin Korus, Anthony O. Adesemoye

Department of Plant Pathology: Faculty Publications

Wet weather that persisted during much of the 2015 growing season proved to be very favorable for disease development in several crops across Nebraska. In particular, diseases caused by fungi were favored by repeated rainfall events and high relative humidity, fog, etc., that supported the production of more spores and continuous plant infection. On some susceptible varieties and hybrids, diseases developed early and quickly eventually reaching moderate to severe levels. Foliar fungicides were applied one or more times to some crops in an effort to mitigate losses due to disease. However, low crop prices and narrow profit margins made foliar …

Corn Disease Update, Tamra A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The 2015 corn crop was impacted by several corn diseases from the beginning to the end of the season and in all areas of Nebraska. The increased severity and incidence of some diseases was largely due to the extended periods of favorable weather conditions in varying parts of the state that supported the increase in some diseases. In particular, frequent rainfall and high relative humidity were especially favorable for several fungal diseases. Unfortunately, almost all diseases of corn (except rusts) are caused by pathogens that can successfully overwinter in Nebraska. For this reason, making detailed notes on disease development and …

Trivapro A + Trivapro B Application Timing And Disease Efficacy In Field Corn In Nebraska, 2015, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was to evaluate foliar fungicides and application timings for crop response and foliar disease efficacy. Irrigated corn was grown based on Nebraska Extension irrigation recommendations at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8 % OM and the previous crop was soybean. Reduced tillage was performed to the field prior to planting. Corn (DKC 65-79 RIB, tolerant to grey leaf spot (GLS)) was planted at approximately 34,000 seed/A on 26 May. Seven treatments were arranged in a randomized complete block design with six replications. …

Foliar Fungicide Comparison For Southern Rust Management, Stay Green, Push Lodging, And Yield In Nebraska, 2015, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was to compare foliar fungicides for southern rust (SR) efficacy. Irrigated corn was grown based on Nebraska Extension irrigation recommendations at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8 % OM and the previous crop was soybean. Reduced tillage was performed to the field prior to planting. Corn (DKC 65-79 RIB, tolerant to gray leaf spot (GLS)) was planted at approximately 34,000 seed/A on 26 May. Eight treatments were arranged in a randomized complete block design with six replications. . . . Stalk lodging …

Fungicide And Herbicide Effects On Grey Leaf Spot In Nebraska Field Corn, 2015, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was to compare foliar fungicides applied to three growth stages of corn for grey leaf spot (GLS) efficacy. Irrigated corn was grown based on Nebraska Extension irrigation recommendations at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8 % OM and the previous crop was soybean. Reduced tillage was performed to the field prior to planting. Corn (DKC 65-79 RIB, tolerant to gray leaf spot (GLS)) was planted at approximately 34,000 seed/A on 26 May. Five treatments were arranged in a randomized complete block design …

A Foliar Fungicide Plus Herbicide Tank Mixture Evaluation In Field Corn In Nebraska, 2015, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was to evaluate the tank mixture of Laudis herbicide plus Stratego YLD fungicide for corn response. Irrigated corn was grown based on Nebraska Extension irrigation recommendations at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8 % OM and the previous crop was soybean. Reduced tillage was performed to the field prior to planting. Corn (DKC 65-79 RIB, tolerant to gray leaf spot (GLS)) was planted at approximately 34,000 seed/A on 26 May. Four treatments were arranged in a randomized complete block design with six …

Corn Disease Profiles: Diseases Favored By Dry Conditions, Tamra A. Jackson-Ziems, Anthony O. Adesemoye, Loren J. Giesler, Robert M. Harveson, Kevin A. Korus, Stephen N. Wegulo

Department of Plant Pathology: Faculty Publications

Extension Circular 1910 (EC1910)

Extreme weather events are predicted to become increasingly common and could bring periods of drought as well as intense rainfall events. Wet conditions are favorable for many plant pathogens and the development of diseases, but some diseases may also develop during or following dry weather. The timing during the season when dry conditions occur, as well as other factors, such as temperature, impact which diseases develop and when. The list summarizes some of the most common corn diseases that can develop during dry conditions: Seedling Root Rot Diseases, Nematodes, Common Smut, Rust Diseases Charcoal Rot, Stalk …

Corn Disease Profiles: Diseases Favored By Wet Conditions, Tamra A. Jackson-Ziems, Anthony O. Adesemoye, Loren J. Giesler, Robert M. Harveson, Kevin A. Korus, Stephen N. Wegulo

Department of Plant Pathology: Faculty Publications

Extension Circular 1909 (EC1909)

Extreme weather events are predicted to become increasingly common and could bring periods of more intense rainfall. Wet conditions are favorable for many plant pathogens and the development of diseases. Seasonal timing when these conditions occur, as well as other factors such as temperature, impact which diseases develop and when. Listed, described, and illustrated are some common corn diseases favored by wet conditions: Pythium Root Rot, Eyespot, Northern Corn Leaf Blight, Gray Leaf Spot, Physoderma Brown Spot, Rust Diseases (Puccinia spp.), Stalk and Crown Rot Diseases (such as those caused by Fusarium and Diplodia spp.), …

Association Of Neonectria Macrodidyma With Dry Root Rot Of Citrus In California, A. O. Adesemoye, J. S. Mayorquin, B. B. Peacock, K. Moreno, S. Hajeri, R. Yokomi, A. Eskalen

Department of Plant Pathology: Faculty Publications

During yearly surveys that started in 2010 to identify pathogens associated with dry root rot disease of citrus in California, samples with root rot symptoms were collected in Tulare County. Small pieces of tissue from root samples were plated onto potato dextrose agar amended with 0.01% tetracycline and incubated at 25°C. Pure cultures of fungal isolates were identified by morphology and sequence analysis of the Internal Transcribed Spacer and Beta Tubulin regions. Neonectria macrodidyma (Cylindrocarpon macrodidymum) was first recovered in 2011 and has subsequently been recovered multiple times from citrus samples. The pathogen appeared to be widely distributed …

Shrubland Resilience Varies Across Soil Types: Implications For Operationalizing Resilience In Ecological Restoration, Carissa L. Wonkka, Dirac L. Twidwell, Jacob B. West, William E. Rogers

Department of Agronomy and Horticulture: Faculty Publications

In ecosystems with alternative stable states, restoration success can be thought of as overcoming the resilience of an undesirable state to promote an alternative state that yields greater ecosystem services. Since greater resilience of undesirable states translates into reduced restoration potential, quantifying differences in resilience can enhance restoration planning. In the context of shrub- encroached rangeland restoration, shrubland resilience is the capacity of a woody vegetated state to absorb management interventions designed to produce a more desirable grass- dominated state, and remain within its current regime. Therefore, differences in the resilience of a state can be quantifi ed in a …

Growing Sensitivity Of Maize To Water Scarcity Under Climate Change, Qingfeng Meng, Xinping Chen, David B. Lobell, Zhenling Cui, Yi Zhang, Haishun Yang, Fusuo Zhang

Department of Agronomy and Horticulture: Faculty Publications

Climate change can reduce crop yields and thereby threaten food security. The current measures used to adapt to climate change involve avoiding crops yield decrease, however, the limitations of such measures due to water and other resources scarcity have not been well understood. Here, we quantify how the sensitivity of maize to water availability has increased because of the shift toward longer-maturing varieties during last three decades in the Chinese Maize Belt (CMB). We report that modern, longer-maturing varieties have extended the growing period by an average of 8 days and have significantly offset the negative impacts of climate change …

Information Thermodynamics Of Cytosine Dna Methylation, Robersy Sanchez Rodriguez, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Cytosine DNA methylation (CDM) is a stable epigenetic modification to the genome and a widespread regulatory process in living organisms that involves multicomponent molecular machines. Genome-wide cytosine methylation patterning participates in the epigenetic reprogramming of a cell, suggesting that the biological information contained within methylation positions may be amenable to decoding. Adaptation to a new cellular or organismal environment also implies the potential for genome-wide redistribution of CDM changes that will ensure the stability of DNA molecules. This raises the question of whether or not we would be able to sort out the regulatory methylation signals from the CDM background …

Horizontal Gene Acquisitions, Mobile Element Proliferation, And Genome Decay In The Host-Restricted Plant Pathogen Erwinia Tracheiphila, Lori R. Shapiro, Erin D. Scully, Timonthy J. Straub, Jihye Park, Andrew G. Stephenson, Gwyn A. Beattie, Mark L. Gleason, Roberto Kolter, Miguel C. Coelho, Consuelo M. De Moraes, Mark C. Mescher, Olga Zhaxybayeva

Department of Agronomy and Horticulture: Faculty Publications

Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains of the cucurbit bacterial wilt pathogen Erwinia tracheiphila (Enterobacteriaceae) isolated from infected squash plants in New York, Pennsylvania, Kentucky, and Michigan. These genomes exhibit a high proportion of recent horizontal gene acquisitions, invasion and remarkable amplification of mobile genetic elements, and pseudogenization of approximately 20% of the coding sequences. These genome attributes indicate that E. tracheiphila recently emerged as a …

Herbicide Options For Effective Weed Management In Dry Directseeded Rice Under Scented Rice-Wheat Rotation Of Western Indo- Gangetic Plains, Vijay Singh, Mangi L. Jat, Zahoor A. Ganie, Bhagirath S. Chauhan, Raj K. Gupta

Department of Agronomy and Horticulture: Faculty Publications

Farmers' participatory field trials were conducted at Madhuban, and Taraori, the two participatory experimental sites/locations of the Cereal Systems Initiative for South Asia (CSISA), a collaborative project of IRRI and CIMMYT in Karnal district of Haryana, India, during Kharif (wet season) 2010 and 2011. This research aimed to evaluate preemergence (PRE) and postemergence (POST) herbicides for providing feasible and economically viable weed management options to farmers for predominant scented rice varieties. Treatments with pendimethalin PRE fb bispyribac-sodium þ azimsulfuron POST had lower weed biomass at 45 days after sowing (DAS). At Madhuban, highest grain yield of scented basmati rice (3.43 …

Prospects For Increasing Sugarcane And Bioethanol Production On Existing Crop Area In Brazil, Fabio R. Martin, Geraldo B. Martha,Jr, Kenneth G. Cassman, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

This article assesses sugarcane yield gaps (YG) in Brazil to determine the degree to which production can be increased without land expansion. In our scenario assessments, we evaluated how much of the projected sugarcane demand to 2024 (for both sugar and bioethanol) can be satisfied through YG closure. The current national average yield is 62% of yield potential estimated for rainfed conditions (i.e., a YG of 38%). Continuing the historical rate of yield gain is not sufficient to meet the projected demand without an area expansion by 5% and 45% for lowand high-demand scenarios, respectively. Closing the exploitable YG to …

Glyphosate-Resistant Weed Control And Soybean Injury In Response To Different Ppo-Inhibiting Herbicides, Jatinder S. Aulakh, P. S. Chahal, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

In Nebraska, 5-enolpyruvyl shikimate-3-phosphate synthase (EPSPS) as well as acetolactate synthase (ALS)-inhibitor-resistant weeds occur in many soybean fields where herbicides from these modes-of-action have been frequently used in the past. Currently, the protoporphyrinogen oxidase (PPO)-inhibitors are the only effective herbicides for POST control of both glyphosate- and ALS-inhibitor-resistant weeds in soybean. Greenhouse experiments were conducted in 2014 to evaluate the efficacy of PPO-inhibitors applied POST for the control of three glyphosate-resistant (GR) weeds and potential for soybean injury, when applied at two growth stages. All herbicide treatments controlled 10- and 20-cm tall GR common waterhemp ≥ 95% at 21 DAT. …

Estimation Of The Degree Of Diversity For Some Iraqi Wheat Varieties Through Issr, Srap And Rapd Markers, Dhafir H. Al-Kaab, Majid Sh. Hamdalla, Ismail M. Dweikat, Noora J. Al-Saedi

Department of Agronomy and Horticulture: Faculty Publications

DNA-based molecular markers such as Inter Simple Sequence Repeat (ISSR), Sequence-Related Amplified polymorphism (SRAP) and Random Amplified Polymorphic DNA (RAPD) were used in this study to examine the genetic differences among sixteen Iraqi wheat varieties. Seventy three primers out of 177 were reproducible and showed clear amplified bands. The degree of genetic diversity, Polymorphism information content (PIC) and resolving power (RP) were estimated. All the studied molecular markers were informative and showed good ability to classify and distinguish 16 wheat varieties. Total number of polymorphic bands is 134, 221 and 55 for ISSR, SRAP and RAPD respectively. PIC and RP …

Nutrients In The Nexus, Eric A. Davidson, Rachel L. Nifong, Richard B. Ferguson, Cheryl Palm, Deanna L. Osmond, Jill S. Baron

Department of Agronomy and Horticulture: Faculty Publications

Synthetic nitrogen (N) fertilizer has enabled modern agriculture to greatly improve human nutrition during the twentieth century, but it has also created unintended human health and environmental pollution challenges for the twentyfirst century. Averaged globally, about half of the fertilizer-N applied to farms is removed with the crops, while the other half remains in the soil or is lost from farmers’ fields, resulting in water and air pollution. As human population continues to grow and food security improves in the developing world, the dual development goals of producing more nutritious food with low pollution will require both technological and socioeconomic …

The C-Terminal Motif Of Siago1b Is Required For The Regulation Of Growth, Development And Stress Responses In Foxtail Millet (Setaria Italica (L.) P. Beauv), Xiaotong Liu, Sha Tang, Guanqing Jia, James C. Schnable, Haixia Su, Chanjuan Tang, Hui Zhi, Xianmin Diao

Department of Agronomy and Horticulture: Faculty Publications

Foxtail millet (Setaria italica (L.) P. Beauv), which belongs to the Panicoideae tribe of the Poaceae, is an important grain crop widely grown in Northern China and India. It is currently developing into a novel model species for functional genomics of the Panicoideae as a result of its fully available reference genome sequence, small diploid genome (2n=18, ~510 Mb), short life cycle, small stature and prolific seed production. Argonaute 1 (AGO1), belonging to the argonaute (AGO) protein family, recruits small RNAs and regulates plant growth and development. Here, we characterized an AGO1 mutant (siago1b) in foxtail millet, which …

Genomic Prediction Models For Grain Yield Of Spring Bread Wheat In Diverse Agro-Ecological Zones, C. Saint Pierre, Juan Burgueño, Jose Crossa, G. Fuentes Dávila, P. Figueroa López, E. Solís Moya, J. Ireta Moreno, V. M. Hernández Muela, V. M. Zamora Villa, P. Vikram, K. Mathews, C. Sansaloni, D. Sehgal, Diego Jarquin, P. Wenzl, Sukhwinder Singh

Department of Agronomy and Horticulture: Faculty Publications

Genomic and pedigree predictions for grain yield and agronomic traits were carried out using high density molecular data on a set of 803 spring wheat lines that were evaluated in 5 sites characterized by several environmental co-variables. Seven statistical models were tested using two random cross-validations schemes. Two other prediction problems were studied, namely predicting the lines’ performance at one site with another (pairwise-site) and at untested sites (leave-one-site-out). Grain yield ranged from 3.7 to 9.0 t ha⁻¹ across sites. The best predictability was observed when genotypic and pedigree data were included in the models and their interaction with …