Source: UNIVERSITY OF FLORIDA submitted to
A SYSTEMS APPROACH TO IMPROVING ABIOTIC STRESS TOLERANCE IN PEANUT
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
EXTENDED
Funding Source
Reporting Frequency
Annual
Accession No.
1000595
Grant No.
2013-67013-21108
Project No.
FLAW-2013-02139
Proposal No.
2013-02139
Multistate No.
(N/A)
Program Code
A1141
Project Start Date
Sep 1, 2013
Project End Date
Aug 31, 2018
Grant Year
2013
Project Director
Rowland, D. L.
Recipient Organization
UNIVERSITY OF FLORIDA
207 GRINTER HALL
GAINESVILLE,FL 326115500
Performing Department
AG-AGRONOMY
Non Technical Summary
Maintaining sustainable crop production under limited water resources has become the single most important challenge in the U.S. agricultural industry and worldwide. To find solutions to this challenge, we aim to take a top-down approach, integrating crop management, physiological screening, and genetic expression evaluation of peanut cultivars in both southwest and southeast U.S. environments. Ultimately, we will evaluate diverse germplasm for the capacity to physiologically acclimate to a water conservative production system our team has developed. Specifically, we will: 1) investigate the physiological and molecular basis of crop response to abiotic stress that occurs in limited water production systems, and the role of stress acclimation in this response, 2) develop straightforward crop management protocols that maximize plant acclimation capacity and effective water use while maintaining economic and environmental sustainability, and 3) use physiological and molecular methods to assist in selection and development of abiotic stress-tolerant peanut cultivars. Field trials will be conducted in both Texas and Florida using previously identified genotypes that have shown contrasting abilities to acclimate to mild water deficits early in development, along with a wider screening of genotypes from the core and mini-core collections. Large scale as well as in-depth physiological screening combined with genetic expression analysis will be conducted to elucidate mechanisms behind abiotic stress tolerance. This project will ultimately provide improved germplasm with improved acclimation potential that, when combined with our water conservative production system, will deliver optimized production in water limited environments.
Animal Health Component
0%
Research Effort Categories
Basic
50%
Applied
40%
Developmental
10%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
11102101020100%
Knowledge Area
111 - Conservation and Efficient Use of Water;

Subject Of Investigation
0210 - Water resources;

Field Of Science
1020 - Physiology;
Goals / Objectives
Our major goals in the project are: 1) investigate the physiological and molecular basis of crop response to abiotic stress that occurs in limited water production systems, and the role of stress acclimation in this response, 2) develop straightforward crop management protocols that maximize plant acclimation capacity and effective water use while maintaining economic and environmental sustainability, and 3) use physiological and molecular methods to assist in selection and development of abiotic stress-tolerant peanut cultivars.
Project Methods
This project will focus on physiological and genetic screening of germplasm from the core and mini-core collections as well as current breeding lines from the Texas (Texas Tech University), New Mexico (New Mexico State University), and Florida (University of Florida) programs. The project will be conducted in Years 1, 2, and 3 of the project across a range of regions and sites. At each site, the overall plot design will consist of a split plot design with at least three replications (determined by space available at each location) with water treatments as the main plot and genotypes as subplots. Overall management of the crop will follow best management practices for the particular region. Water treatments. Two water treatments will be applied: 60% PA and approximately 100% evapotranspiration (ET). The 60% PA treatment will consist of applying 60% ET replacement for the first 45 days after planting (DAP) and then fully irrigating the crop for the remainder of the season, except during a one-week period in mid-season when drought tolerance will be evaluated (see below). The 100% ET treatment will consist of 100% ET replacement for the entire growing season. Genotypes to be utilized. Previous work in our labs and by others has identified several genotypes showing improved production characteristics under water-deficit irrigation and elevated temperature (described above). The central theme of the proposed work is to investigate the response of novel, stress-tolerant peanut germplasm to a primed acclimation production model in semi-arid and humid environments. Initial experiments on genotype response to PA irrigation will include 70 genotypes from the U.S. mini-core collection in addition to 15 selected genotypes. Regional check cultivars with known tolerance and sensitivity to water-deficit and thermal stress will be employed as controls and to develop PA-canopy temperature models for current production schemes. Screening methods - physiological performance and gene response under acclimation. Physiological measurements will occur on two scales: 1) general physiological and field performance; and 2) in-depth physiological performance measurements taken in all water treatments on 15 of the genotypes previously identified as having contrasting acclimation potential. The general scale measurements will occur on all genotypes within the test at all locations; therefore, because of the sheer numbers of genotypes to screen, these will be more general performance measures. These measurements will be taken every 30 days during the growing season beginning at 30 DAP for a total of 4 measurement periods prior to harvest (30, 60, 90, 120 DAP). The general measurements will include Normalized Difference Vegetation Index (NDVI), paraheliotropism, SPAD, yield, and grade. Tissue samples for gene expression profiling by next-generation sequencing (RNA-Seq) will be collected for all genotypes during stages of the physiological measurement. Leaf, root, and pod (90 and 120 DAP) will be harvested at the time of physiological measurements, flash-frozen in liquid nitrogen, and stored at -80C. Following final harvest, physiological (including canopy temperature data), morphological, environmental, and yield analysis will be performed to determine which specific tissue samples will be used for gene expression studies (described in detail below). Anovel proteomics approach will be applied to analyze the effects of acclimation on the proteome of peanut pod tissues. Single Nucleotide Polymorphism (SNP) markers in the candidate genes identified by MapMan will be identified by SNP variant analysis among the tolerant and susceptible genotypes by DNAStar 10.1.2 suite. These markers will be used for both mapping and marker assisted selection in peanut breeding for abiotic stress tolerance. General acclimation potential across all the genotypes at each location will be quantified by examining the differences among lines in general physiological performance when exposed to mid-season drought stress and end-season yield and grade variation between PA and 100% treatments for each line. The influence of genotype X environment can also be evaluated by comparing among locations. For the lines where contrasting performance has already been previously demonstrated under controlled conditions, the more in-depth physiological and molecular mechanisms responsible for the priming response will be evaluated from the fine-scale measurements. In addition to the biological assays used to assess acclimation and acclimation potential (plasticity), we will use harvest index and yield penalty assessment within a set of treatments for each genotype to identify the best candidates for breeding and RNA-seq analysis. Controlling stress level for accurate PA application. Assessment of thresholds and season-long monitoring of the BIOTIC model using measurements of infrared canopy temperature will be evaluated in Years 1, 2, and 3 at two of the sites established from both FL and TX. Efforts: This integrated, multi-disciplinary proposal will provide insight into the underlying physiological and molecular mechanisms controlling peanut abiotic stress responses, as well as the impact of those responses on cellular physiology, biochemistry, and whole-plant physiology. This project is closely allied AFRI-1141 and directly addresses pre-breeding and development of novel approaches to phenotyping and the genpotype-phenotype and SNP data generated here will directly feed into public peanut breeding programs. We will be serving the grower community in this project by establishing the framework for more efficient irrigation scheduling models designed for the limited input production regions relying on regulated deficit irrigation for agronomic sustainability. Such models will improve the efficiency of irrigation for growers and ultimately provide a more consistent peanut crop in yield, maturity, and flavor. Our extension efforts will disseminate the information from this project to growers in the southwest and southeast. There will be ample opportunity for the on-going work in this project to be integrated into the educational mission of the participating institutions. One of the key aspects of the training that students will receive in this project is that it will be multi-disciplinary, extending from gene function, spanning molecular genetics to physiology and agronomy. Training from this project will teach students how to address basic biological problems with functional genomics and classical molecular approaches and how to integrate these findings into agronomy and crop physiology. All participating institutions have strong and aggressive outreach programs that attract high school students and undergraduate students from diverse backgrounds. Analysis, assessment, interpretation, and dissemination of results: Physiological data will be subject to analysis of variance utilizing general linear mixed models with appropriate fixed and random factors defined. Comparative gene expression profiling of sequencing data will be done to identify molecular and regulatory responses between contrasting stress-tolerant genotypes and acclimated and non-acclimated treatments. Treatment differences associated with PA for check cultivars will be used to provide recommendations to growers for optimal water application periods and possible developmental stages where water application could be delayed or reduced due to inadequate irrigation supplies without negatively affecting NV. By correlating the NV with optimal irrigation applied per area, recommendations can be made to growers who have limited irrigation supplies during a given growing season regarding what acreage can be supported for maximal economic return. This information has been requested by growers and manufacturers in the region.

Progress 09/01/16 to 08/31/17

Outputs
Target Audience:Audiences included: scientific professional societies through invited seminars and submitted abstracts; U.S. universities through invited seminars; international universities through invited seminars; producer groups through extension workshops and field days; undergraduate and graduate students through formal classes. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Students trained One MS (K. Racette) and one PhD (B. Zurweller) student were involved in the field trials conducted in Florida. Ms. Racette received a PhD assistantship to continue to work on related projects for 2016-2020. Mr. Zurweller presented his results at the annual meeting of the Trisocieties, Agronomy, Crops, and Soil Association in November 2016. At TTU, two M.S. students (TTU Biotechnology; Poornasree Kumar and Ashwini Challa) aided in carrying out the transcriptome analysis. One Ph.D. student (TTU Plant and Soil Sciences; Haydee Laza) also participated in the transcriptome analysis. Ms. Kumarapathiranalage will graduate in May 2017. How have the results been disseminated to communities of interest?International and national presentations have been given at conferences and invited seminars have been presented during the reporting period. In addition, the results of the project continue to be disseminated through extension workshops, training conferences, and popular press. An interactive functional genomics website was designed and launched in November 2015 continues to be maintained. This website is titled: Peanutomics.org What do you plan to do during the next reporting period to accomplish the goals?The team is currently working on three manuscripts in draft associated with the dissertation of B. Zurweller (slated to graduate in December, 2017. Focus is now on the additional data analysis, and synthesis of results for completion of the six (and possibly additional) manuscripts.

Impacts
What was accomplished under these goals? FLORIDA: there were two project conducted in Florida for the reporting time period (8/2016-8/2017). Project 1:The second year of a field study continued from 2015 was completed in 2016 at the University of Florida's Plant Science Research and Education Unit in North-Central Florida (29° 24' 38" N, 82° 10' 12" W). The experimental design consisted of a split plot arrangement in a randomized complete block design with whole plots were irrigation treatments consisting of (i) 1.9 cm per application (100%); (ii) a primed acclimation (PA) treatment consisting of 1.1 cm of water per application until mid-bloom and then 1.9 cm of water for the remainder of the season (60%PA); (iii) 1.1 cm of water per application for the entire season (60%); and (iv) a rainfed control (RF). Sub-plots consisted of four genotypes, two Valencia genotypes (Arachis hypogaea L. var. fastigiata) COC 041 (PI 493631) and New Mexico Valencia C (NMVC), and two runner (Arachis hypogaea L. var. hypogaea) commercial cultivars FloRunTM '107' and TUFRunnerTM '511'. Mini-rhizotron tubes were installed directly into and parallel to the row at a 45° angle immediately after crop emergence and root imaging occurred at 21, 28, 35, 49, and 75 days after planting (DAP). Measurements of leaf area index (LAI) were recorded on 28, 35, 49, 64, and 77 DAP in both site years (LI-COR, Lincoln, Nebraska). Harvest was completed when pods were mature. Differences in TRL growth was observed among the peanut genotypes at the first measurement day at 21 DAP. Greater root growth occurred in COC 041 when compared to all other genotypes. At 28 DAP greater separation in TRL occurred and the difference continued to magnify at 35 DAP after which the TRL growth rate began to decrease. Total root length measurements after 35 DAP show two delineations between the peanut genotypes. Total root length was similar between the two Valencia market types. Total root length development also varied among peanut genotypes by soil depth. From 0-20 cm soil depth, COC 041 had a greater TRL than all other genotypes across all measurement dates. Irrigation management impacted LAI development over the growing season. The LAI was greatest in the 100% irrigation treatment which was larger than the RF treatment, although similar to the 60%PA and 60% irrigation treatments. Irrigation treatments of 100%, 60%PA, and 60% had higher pod yields relative to the RF control of 23, 15, and 17%, respectively. In 2016, pod yield of FloRunTM '107' was 672 kg ha-1 greater than TUFRunnerTM '511'. Yields were significantly reduced among all genotypes in 2016, a likely impact of less mid-season precipitation resulting in water stress among all genotypes and irrigation treatments. This resulted in a genotypic pod yield decline in 2016 of 21, 30, 68, and 59% with FloRunTM '107', TUFRunnerTM '511', NMVC, and COC 041, respectively. Project 2: A field study was conducted during 2016 in an adjacent plot area to Project 1.The experimental design consisted of a split plot arrangement in a randomized complete block design. The whole plots were irrigation treatments consisting of (i) 1.9 cm per application (100%) for the first 50 days after planting (DAP); (ii) a primed acclimation (PA) treatment consisting of 1.1 cm of water per application for the first 50 DAP. Sub-plots consisted of two genotypes used in Project 1, COC 041 and TUFRunnerTM '511'. Two mini-rhizotron tubes were installed in each plot directly into and parallel to the row at a 45° angle immediately after crop emergence. At each measurement date, images were captured at 13.5 mm increments along the mini-rhizotron tubes using a camera system (Bartz Technology Corporation, Carpinteria, CA). Root parameters analysis was conducted using WinRHIZO Tron software (Regent Instruments Inc., Quebec, Canada). Root image sampling dates occurred at 60, 67, 75, 82, and 88 days after planting (DAP). Measurements of leaf level gas exchange were recorded using a LICOR-6400XT portable photosynthesis system at 61, 68, 75, 82, 89, and 96 DAP (LICOR, Lincoln, Nebraska). Volumetric soil water content was quantified using time domain reflectometry (TDR) with the TRIME-PICO IPH/T3 probe (IMKO, Ettlingen, Germany). These measurements were recorded prior to sunrise and sunset at 61, 68, 75, 82, 89, and 96 DAP to correspond with the gas exchange measurements. Soil water depletion was estimated for each day by taking the difference between pre-dawn and pre-dusk for each quantified soil depth. Plots were harvested when mature. The root system characteristics varied among the two peanut genotypes in this study. TUFRunnerTM '511' had less overall TRL with greater coarse roots with diameter classes greater than 3.5 mm 10-1. The early season irrigation did influence the genotypic RSA. The peanut genotype COC 041 had similar amounts of TRV in the top 60 cm when comparing the two irrigation treatments. The genotype COC 041 did respond to the 60%PA treatment by having greater TRV growth at the deepest quantified soil depth range from 60-80 cm. TUFRunnerTM '511' plants irrigated with the 100% irrigation treatment had greater TRV in the soil depth ranges of 0-20 and 20-40 cm when compared to the 60%PA irrigation treatment. Total root volume of genotype TUFRunnerTM '511' was reduced in the 100% irrigation treatment at 60-80 cm of soil. A quadratic regression model was fitted to examine the relationship between the daily transpiration flux and total soil water depletion to a soil depth of 70 cm. A moderately high coefficients of determination (R2=0.61 and 0.67) was estimated for the genotypes COC 041 and TUFRunner '511', respectively. Under high amounts of soil water content, the estimated percent of soil water depletion occurring in the top 30 cm of soil was 86, 66, and 71% at 61, 75, and 89 DAP, respectively. When the soil reached drier conditions the predominant percent of soil water depletion occurred at 30-60 cm of soil depth. On these dates of 68, 82, and 96 DAP the estimated percent of soil water depletion at 30-60 cm was 59, 67, and 76%, respectively. At 61, 68, and 82 DAP TUFRunnerTM '511' had greater mid-morning transpiration rates than COC 041. This demonstrates that the two genotypes have the ability to maintain similar amounts of transpiration following a wetting event when no water deficit stress is present. TEXAS: Samples from the Physiology Experiments were processed for RNA-Seq and gene expression analysis. A drought-tolerant runner genotype (also used in a previous experiment and for transcriptome analysis) was selected for whole-genome sequencing using single molecule real time sequencing (PacBio) at the Interdisciplinary Center for Biotechnology Research at the University of Florida. Tetraploid peanut genotype C76-16 is being sequenced using a combination of 4 different technologies namely Illumina HiSeq, Pacbio RS II, Bionano, and HiC (Phase genomics). We generated 180X data using HiSeq and 25X data using Pacbio sequencers. This data was assembled using Discovar software followed by SSPACE and scaffolds were generated. We reached the target genome size of 2.8 GB using this assembly algorithm. However the assembly was fragmented and to move forward, we started HiC sequencing through Phase Genomics. After first assembly using Phase genomics algorithm, we obtained decent scaffolds and contig N50 improved with PBJelly assembly. Now we are in the process of integrating the scaffolds with Bionano scaffolds and finishing the genome assembly.

Publications

  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Zurweller, B.A., D.L. Rowland, B. Tillman, P.P. Payton, and K.R. Kottapalli. Identification of traits for optimized root system architecture in peanut. National Association of Plant Breeders. 2017 Aug. 7-10, Davis, CA.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2016 Citation: Zurweller, B.A., D.L. Rowland, B. Tillman, K.L. Migliaccio, P.P. Payton, J. Erickson, and D.L. Wright. Peanut genotypic root architecture in response to irrigation. ASA, CSSA, and SSSA: Resilience emerging from scarcity and abundance. 2016 Nov. 6-9; Phoenix, Arizona.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Zurweller, B.A., and D.L. Rowland. PeanutFARM and the impacts of irrigation on peanut development. Georgia Peanut Farm Show & Conference. 19 Jan. 2017; Tifton, GA.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2016 Citation: Zurweller, B.A., E.C. Carter, R. Gloaguen, and D.L. Rowland. Impacts of irrigation on peanut development. Irrigation and Crop Management Field Day. 13 Sept. 2016; Escambia County, FL.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2016 Citation: Zurweller, B.A., K. Racette, and R. Gloaguen. Impacts of irrigation on root development and inter-generational stress in peanut. 2016 UF/IFAS Peanut Field Day. 11 Aug. 2016; Marianna, FL.


Progress 09/01/15 to 08/31/16

Outputs
Target Audience:Audiences included: scientific professional societies through invited seminars and submitted abstracts; U.S. universities though invited seminars; international universities through invited seminars; producer groups through extension workshops and field days; undergraduate and graduate students through formal classes. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Students trained One MS (K. Racette) and one PhD (B. Zurweller) student were involved in the field trials conducted in Florida. Ms. Racette received a PhD assistantship to continue to work on related projects for 2016-2020. Mr. Zurweller presented his results at the International Society of Root Research in Canberra, Australia in October 2015. At TTU, two M.S. students (TTU Biotechnology; Poornasree Kumar and Ashwini Challa) were hired to carry out the glasshouse priming study and transcriptome analysis. One Ph.D. student (TTU Plant and Soil Sciences; Haydee Laza) was hired to direct the field trials in Lubbock and direct the transcriptome analysis. All students are on track to graduate. Ms. Laza presented data from this project at two meetings: Annual Meeting of the Southern Section of the American Society of Plant Biology in April and the Annual Meeting of the American Society of Plant Biology in July. Nethanji Kumarapathiranalage (M.S. Biotechnology) presented her work on gene expression and acclimation at the Annual Meeting of the Southern Section of the American Society of Plant Biology in April. Ms. Kumarapathiranalage will graduate in May 2017. How have the results been disseminated to communities of interest?International and national presentations have been given at conferences and invited seminars have been presented during the reporting period. In addition, the results of the project continue to be disseminated through extension workshops, training conferences, and popular press. An interactive functional genomics website was designed and launched in November 2015 during the 2015 AAGB conference in Brisbane, Australia. This website is titled: Peanutomics.org What do you plan to do during the next reporting period to accomplish the goals?The team is currently working on two manuscripts in draft and have planned at least six additional manuscripts in preparation. To accomplish these goals during the remainder of the project, emphasis will be placed on completing the measurements and plot harvest for the 2016 season in both FL and TX. Focus will then switch to data analysis, and synthesis of results for completion of the six (and possibly additional) manuscripts. Mr. Zurweller is planned to finish his PhD degree program at the termination of the project in 2017.

Impacts
What was accomplished under these goals? Florida Project 1: The field study was initiated in 2015 at the University of Florida's Plant Science Research and Education Unit in North Central Florida (29° 24' 38" N, 82° 10' 12" W). The soil is classified as an Arredondo sand (Loamy, siliceous, semiactive, hyperthermic Grossarenic Paleudults). Daily meteorological data will be recorded using an automated weather station located within 1500 m of the experiment. Both canopy and root development varied among the peanut genotypes over the growing season. Measurements of leaf area index (LAI) after 48 days after planting (DAP) showed an increased amount of leaf area index when comparing the runner (TUFRunnerTM '511'and FloRunTM '107') to the valencia (New Mexico Valencia C and COC 041) peanuts. The opposite trend was observed with the total amount of measured root length over the growing season. This trend was increased amounts of total root length following 35 DAP when comparing valencia to runner peanuts. Pod yield of particular peanut genotypes did vary among the irrigation treatments. These differences were an increase in pod yield when comparing the 100% irrigation treatment to both the PeanutFARM scheduling and rainfed control irrigation treatments for peanut genotypes of COC 041 and FloRunTM'511'. The 100% treatment had similar yields to the 60% and 60PA irrigation treatments for all genotypes. Irrigation treatments were also averaged across genotypes for an overall impact of the irrigation effect on pod yield of all genotypes. Project 2: Irrigation, peanut genotypes, and illumination treatments were set up in a randomized complete block with a split-split plot arrangement with irrigation as the whole plot and peanut genotype and light treatments as the sub-plots. Rainout shelters were used to shed rainfall on all plots until mid-bloom. Irrigation treatments included: 1) 1.9 cm (100%) for the entire season; and 2) a PA treatment that received 1.1 cm (60% of optimum treatment) until mid-bloom and 1.9 cm following mid-bloom. Irrigation was applied using surface drip irrigation with a 30 cm emitter spacing producing 3721 L hr-1 100 m-1 at 69 kPa (JAIN Irrigation Inc, Haines City, FL) and scheduled using tensiometers installed at 0.31 m (Irrometer Company, Inc., Riverside, CA). Irrigation scheduling was determined when tensiometers reached 25-35 kPa in the optimum irrigation treatment (100%) at a depth of 30 cm. Sub-plots were planted as four row plots (7.6 m in length with 0.91 m between rows) of TUFRunner '511'TM and COC 041. Measurements occurred subsequent to the end of the priming period at 44, and at around 68, and 84 DAP. Illumination treatments were implemented with the intention to create plants that transpire (illuminated) and do not transpire (non-illuminated) in the dark. Mini-rhizotron tubes were imaged the day before plots were illuminated. Prior to illuminating, volumetric soil moisture were determined at 15 cm increments along the entire length of the mini-rhizotron tube using a TRIME-PICO IPH/T3 probe using time domain reflectometry (TDR) (IMKO, Ettlingen, Germany). After illumination was initiated, soil water content was measured two hours after dark and mid-morning the following day. Leaf gas exchange, including transpiration, was measured simultaneously with the volumetric soil moisture using the LICOR 6400-XT infrared gas analyzer (LI-COR, Lincoln, Nebraska). 2016: Both Project 1 and 2 were repeated in the field in 2016. Texas: Summary of activities at TTU 2015-2016: Controlled environment studies. Two primed acclimation experiments were conducted in a glasshouse environment at the USDA-ARS Cropping Systems Research Laboratory in Lubbock (Payton Lab). Five selected genotypes (two runner types and three Spanish types) were subjected to water deficit stress from sowing through the initiation of flowering. For priming, water deficit was maintained at approximately 40% volumetric water content as determined by lysimeters. Pots were irrigated twice weekly to maintain a constant water deficit. Leaf gas-exchange was measured before and after irrigation events to physiologically characterize the water-deficit stress and plant growth measurements were made weekly. At anthesis, primed plant pots were irrigated to field capacity and pots were maintained at 80-100% VWC for three weeks. Subsequently, pots (primed and non-primed controls) were subjected to a slow-onset water deficit stress (approximately 10% daily decline in VWC) and leaf gas-exchange was measured to characterize the physiological response. After 10 days of water deficit stress, plants were re-watered and the response to irrigation and recovery was monitored by leaf gas-exchange for one week. For all genotypes, priming resulted in a decreased growth rate from sowing to anthesis that was correlated with lower net CO2 assimilation rates and transpiration rates. Following initiation of full irrigation, growth rates of the acclimated plants were similar to control plants. Primed plants showed slower response to the subsequent water deficit stress and had higher photosynthesis rates compared to non-primed plants at the same soil VWC, suggesting that the priming was successful. Primed plants also showed increased rates fo recovery of photosynthesis following the return to full irrigation. After 2 weeks, all plants, primed and non-primed, showed similar rates of growth, photosynthesis, and water use as controls. Leaf and root samples were collected during key time-points of priming, the slow-onset water deficit, and recovery phases of the experiments. These samples are currently being processed for RNA isolation for transcriptomic response to priming and water deficit stress. Field studies. Two field trials designed to study acclimation response were planted in Lubbock, Texas at the USDA-ARS-CSRL (Payton Lab). Experiment 1 was planted under center pivot irrigation on May 20, 2015. This site received record rainfall in 2015 and no priming was achieved. A second trial was planted at USDA-ARS-CSRL and plots were covered with continuous evapotranspiration assimilation (CETA) chambers to measure acclimation response on the canopy level. Although early season rainfall was significant (250 mm during the first 20 days after planting) and priming was not achieved, the CETA chambers excluded enough rain to conduct late season priming experiments. Plants were irrigated by surface drip and soil water content, plant canopy temperature, soil temperature, and leaf area index were measured continuously. Plants were subjected to 3 water deficit stress and recovery events at the initiation of flowering, peak flowering, and peak pod fill. During each subsequent stress and recovery event, plants showed acclimation of photosynthesis and respiration for longer periods at soil water contents and air temperatures. Leaf, root, and pod samples were collected for RNA and metabolite analysis. Next-generation sequencing: Samples from the Physiology Experiments are currently being processed for RNA-Seq and gene expression analysis. A drought-tolerant runner genotype (also used in the experiments listed above and for transcriptome analysis) was selected for whole-genome sequencing using single molecule real time sequencing (PacBio) at the Interdisciplinary Center for Biotechnology Research at the University of Florida. The data (25X coverage) was analyzed and reads, after error correction, were assembled with an Illumina assembly generated by the Texas Tech University Center for Biotechnology and Genomics (Kottapalli Lab) to obtain scaffolds. These data are being processed for annotation and represent the first tetraploid peanut genome sequence, to date. Data analyzed and manuscript under preparation.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Invited Talk Kameswara Rao Kottapalli, Sandhiya Arun, Pratibha Kottapalli, Diane Rowland, Paxton Payton (2015) RNA-Sequencing to understand mechanisms of drought stress acclimation response in peanut roots. Invited Talk at Advances in Arachis through Genomics and Biotechnology 8th International conference, at Brisbane, Australia.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Nethanji Kumarapathiranalage, Ashwini Challa, Pratibha Kottapalli, Kameswara Rao Kottapalli, Paxton Payton. RNA-Sequencing to understand mechanisms of drought stress acclimation response in peanut leaf. Southern Section of the American Society of Plant Biology, Denton, Texas 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Haydee Laza, Diane Rowland, Jeff Baker, James Mahan, Dennis Gitz, Paxton Payton. Interactive effects of deficit irrigation, elevated temperature, and elevated [CO2] on peanut growth in low irrigation production settings. Annual Meeting of the American Society of Plant Biology, Austin, Texas 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Zurweller, B., D.L. Rowland, P.P Payton, B.Tillman. Peanut genotypic root responses to irrigation. In: Proceedings of International Society of Root Research: Roots Down Under; 2015 Oct. 6-9; Canberra, Australia.
  • Type: Websites Status: Published Year Published: 2016 Citation: Zurweller, B., and D.L. Rowland. PeanutFARM irrigation and harvest tool is now mobile friendly. In: Panhandle Ag e-News; 2016 May. 20.
  • Type: Other Status: Published Year Published: 2016 Citation: Leidner, J. Root work for drought tolerant genectics. In: Southeastern Peanut Farmer; 2016 Jan./Feb., Vol. 54.


Progress 09/01/14 to 08/31/15

Outputs
Target Audience:Audiences include: scientific professional societies through invited seminars and submitted abstracts; U.S. universities through invited seminars; international universities through invited seminars; producer groups through extension workshops and field days; undergraduate and graduate studetns through formal classes. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Several graduate student have now been involved in various projects in FL, TX, and NM. Training activities in physiological evaluation, agronomic assessment, gene responses, breeding, and statistical analyses are occurring through one-on-one and group activities with faculty mentors and advisors. Many of these students have presented at professional scientific meetings on their results (see conference presentation citations). Numerous undergraduate students are also involved in the project and have been trained with all appropriate methods. How have the results been disseminated to communities of interest?International and national presentations have been given at conferences and invited seminars during the reporting period. In addition, the results of the project continue to be disseminated through extension workshops and training conferences. What do you plan to do during the next reporting period to accomplish the goals?We plan on repeating all field trials in FL, TX, and NM to provide replication of field results over time. The same as well as additional measurements and tissue collections are planned based on previous results - this has allowed us to refine our measurements of choice and add what additional information is needed. Greenhouse trials are ongoing and will continue to add a level of assurance of completion of results if rainfall conditions are not adequate for priming. We have successfully designed and constructed rainout shelters in FL; we will be refining some of the elements of the structures and will continue to utilize them in FL to insure priming. We have begun to design and implement laboratory tests of hydrotropism and field tests of hydaulic lift to explain the mechanisms of priming that might differ among peanut genotypes. We plan on continuing these tests in the upcoming year.

Impacts
What was accomplished under these goals? Florida: 2014: irrigation and peanut genotypes treatmentswere randomized in a complete block in split plot arrangement with irrigation as the whole plot and peanut genotype as the sub-plot. The irrigation treatments included: 1) an optimum application amount of 1.9 cm (100%) for the entire season; 2) A season long irrigation reduction of 1.1 cm (60%); 3) a rainfed control. All irrigation was scheduled using the University of Florida's PeanutFARM soil water mass balance scheduling tool. Sub-plots will be planted to four rows (15.2 meters in length with 0.91 meter between rows) of runner (Arachis hypogaea) type peanuts FloRun '107'TM and TUFRunner '511'TM, and Valencia (Arachis fastigiata) type peanuts New Mexico Valencia C and COC 041. Root images, LAI, yield, and grade were evaluated and statistically compared. 2015: Irrigation and peanut genotypes treatmentswere randomized in complete block with a split plot arrangement with irrigation as the whole plot and peanut genotype as the sub-plot. Irrigation will be applied using a lateral move system equipped with variable rate irrigation (VRI) (Lindsey Corporation, Omaha, NE). The irrigation treatments included: 1) irrigation scheduled using the University of Florida's PeanutFARM soil water mass balance scheduling tool with applications at a 1.9 cm amount for the entire season; 2) irrigation scheduled with tensiometers at an optimum application amount of 1.9 cm (100%) for the entire season; 3) PA managed using the treatment #2 to trigger irrigation but with an application of 1.1 cm until mid-bloom and 1.9 cm following mid-bloom; 4) irrigation triggered using #2 but with 1.1 cm application amount for the entire season; and 5) a rainfed control. The tensiometer treatment has sensors installed at 0.31, 0.70, and 0.91 m (Irrometer Company, Inc., Riverside, CA). Irrigation in treatments 2, 3, and 4 will be triggered when the tensiometers reach 30-40 kPa in the optimum irrigation treatment (100%) using tensiometers placed at 30 cm. Sub-plots will be planted to four rows (7.6 meters in length with 0.91 meter between rows) of runner (Arachis hypogaea) type peanuts FloRun '107'TM and TUFRunner '511'TM, and valencia (Arachis fastigiata) type peanuts New Mexico Valencia C and COC 041. Root architecture, LAI, leaf temperature, yield and grade are being evaluated and will be completed by harvest (October 2015). Texas and New Mexico: Conducted drought acclimation study in the greenhouse for 4 genotypes and collected tissue for RNA-Seq experiments. Analyzed the physiology data and selected critical time points for genotype and treatment comparisons. Generated whole root reference transcriptomes for NM Valencia-C and COC041 genotypes. Arrived at a hypothetical model to explain the mechanisms of drought stress acclimation in tolerant COC041 peanut roots. In order to create a RNA-Seq atlas for peanut, sequenced the transcriptome libraries of NM Valencia-C and C76-16 genotypes on HiSeq2500. Assembled raw reads by Trinity software and created whole plant reference transcriptomes for NM Valencia-C and C76-16 genotypes. The assembled contigs/transcripts were annotated and will be used for future comparison of condition/tissue/treatment specific transcriptomes. A second set of experiments were completed to examine the persistence of the acclimation signal by testing the effect of priming on seedling and vegetatively mature plants in the glasshouse. Preliminary analyses suggest that priming by thermal stress in the absence of water deficit stress results in a short-term, transient acclimation response in all genotypes tested to date. The transient nature of the signal is relative to the more persistent response observed in plants exposed to short-term water deficit stress or water-deficit and simultaneous thermal stress. Our initial detection of the signal was based on photosynthetic response to subsequent water deficit or thermal stress, as well as the differential expression of selected heat shock proteins. Interestingly, both priming events result in acclimation to subsequent events, but thermal priming to a lesser degree than water deficit. However, under glasshouse conditions, no statistical differences were measured between thermal- or water-deficit stress-primed plants. Currently, we are preparing leaf and root samples for RNA-seq analysis. Preliminary data from field and glasshouse studies indicate significant differences in root morphology across the genotypes, specifically later root production under water deficit conditions. We are currently developing a model for using canopy temperature response to water deficit and irrigation as a surrogate for root growth and activity. Two field experiments were conducted during 2014 cropping season at USDA-ARS, Lubbock- Texas and Delwin Marrow Farm, Brownfield-Texas. Seeds were planted on May 9, 2014 at Brownfield and harvested on October; In Lubbock seeds were planted on May 14, 2014 and harvested in November. Due to frequent rains during the early season at both locations, plants were not stressed so they were not primed acclimated. Twelve genotypes representing the four market groups were used in this study (COC-041, TMV2, TAMSPAN-90, ICGV - 86051, ICGV -86388, Serenut- 5R, FR-458, Georgia Green, C76-16, ICGS-76, Serenut-6T, Valencia-C). All these genotypes showed promising results in early drought screening studies from previous experiments. Genotype C76-16 and Tamspan-90 showed promising yields under limited irrigation conditions. Gas exchange rate were measured on all genotypes during stress and during recovery. Leaf area, leaf dry weight, SPAD chlorophyll were measured on all genotypes at both locations. Total water received at Lubbock field was 630 mm under full irrigation treatment and 478 mm under limited irrigation treatment. Water received at Brownfield was 670 mm under full irrigation treatment and 502 mm under limited irrigation treatment.

Publications

  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Valencia peanut breeding for increased shelf life, enhanced drought tolerance and improved disease resistance. 2015. N. Puppala, P. Payton, D. Rowland, K.R. Kottapalli, M. Burow, N. Barkley, K. Chenault, S. Sanogo, A. Xavier and G. Sandhu. 5th International Conference on Next Generation Genomics and Integrated Breeding for Crop Improvement. Feb. 18-20, 2015. ICRISAT, Patancheru, India.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Screening of peanut cultivar under water-limited conditions. 2015. Abishek Xavier*, Paxton Payton, James Mahan, Kameswara Rao Kottapalli, Diane L. Rowland, C. Corley Holbrook, Young koo Cho, and Naveen Puppala. American Society of Plant Biologist- Southern Section (SS-ASPB). Dauphin Island, Alabama. March 29, 2015.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Yield and physiological response of different peanut genotypes under water-limited conditions. 2015. Abishek Xavier, Paxton Payton, James Mahan, Kameswara Rao Kottapalli, Diane L. Rowland, Corley Holbrook, Young koo Cho, and Naveen Puppala. American Peanut Research and Education Society (APRES). Charleston, South Carolina. July 16, 2015.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Zurweller, B.A., D. Rowland, B. Tillman, and P. Payton. Peanut Genotypic Root Architecture in Response to Irrigation. American Society of Plant Biologists, Dauphin Island, AL 29 May 2015.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Zurweller, B.A., D. Rowland, B. Tillman, and P. Payton. Peanut Genotypic Root Architecture in Response to Irrigation. American Peanut Research and Education Society, Charleston, SC, 16 July 2015.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Sandhiya Arun, Kameswara Rao Kottapalli, Paxton Payton (2015) Transcriptomics of drought stress acclimation response in Peanut (Arachis hypogaea L.). Poster presentation at ASPB-SS, at Dauphin Island, AL, USA.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Sandhiya Arun, Kameswara Rao Kottapalli, Paxton Payton (2015) Transcriptomics of drought stress acclimation response in Peanut (Arachis hypogaea L.). Poster presentation at Texas Tech University Graduate school competition, Lubbock, TX (Awarded 2nd Prize)
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Kameswara Rao Kottapalli, Paxton Payton, Naveen Puppala (2014) Whole-transcriptome analysis of peanut tissues using next-generation sequencing: Toward an RNA-Seq atlas for NM Valencia C. Invited Talk at Advances in Arachis through Genomics and Biotechnology 7th International conference, at Savannah, Georgia, USA.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Kameswara Rao Kottapalli, Paxton Payton, Naveen Puppala (2014) Charaterization of thermal acclimation response in peanut. Invited Talk at American Peanut Research and Education Society annual conference, at San Antonio, Texas, USA.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Paxton Payton, Diane Rowland, Naveen Puppala, James Mahan, and KR Kottapalli (2014). Primed acclimation as tool for water conservation and crop management in low irrigation environments. Invited seminar, Hawkesbury Institute for the Environment, Univ. of Western Sydney, Australia.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Kameswara Rao Kottapalli, Zabet-Moghaddam Masoud, Diane Rowland, Wilson Faircloth, Mirzaei Mehdi, Paul Haynes, Paxton Payton (2013). Shotgun label-free quantitative proteomics of water-deficit stressed mid-mature peanut (Arachis hypogaea L.) seeds. Journal of Proteome Research 12: 5048-5057.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Aspinwall, M.J., Loik, M.E., Resco de Dios, V., Tjoelker, M.G., Payton, P., and Tissue, D. 2014. Utilizing intraspecific variation in phenotypic plasticity to bolster agricultural and forest productivity under climate change. Plant Cell Environ. doi: 10.1111/pce.12424. 2014.


Progress 09/01/13 to 08/31/14

Outputs
Target Audience: Audiences include: scientific professional societies through invited seminars and submitted abstracts; U.S. universities through invited seminars; International universities through invited seminars; producer groups through extension workshops and field days; undergraduate and graduate students through formal classes. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Several graduate students have now been involved in the various projects in TX and FL. Training activities are taking place through one-on-one work with faculty mentors and advisors. The students include: Hired Abishek Xavier (will begin his Ph.D. from spring 2015 at New Mexico State University), Bertha Nguku (is in her 2nd year of her Ph.D. at the University of Florida) and Brendan Zurweller (began in Ph.D. at UF in summer, 2014). Numerous undergraduate students have been involved in activities in these projects and have been trained in appropriate methods for physiological assessment in peanut. How have the results been disseminated to communities of interest? Three international presentations have been given (UK, France) at conferences and invited seminars during the reporting period. In addition, the results from the project have been given at numerous extension workshops and training conferences. What do you plan to do during the next reporting period to accomplish the goals? Repeated field trials similar to those conducted in 2014 are scheduled for 2015 to provide replication of field results over time. The same measurements and tissue collections are planned. Continued evaluation of gene response with RNA-seq is scheduled. Greenhouse work has been initiated subsequent to the reporting period in TX due to the inability to achieve adequate priming during the early season because of large rainfall amounts received during this time period. Greenhouse trials have been initiated to test priming response to heat and drought stress by these same cultivars used in the field trials this year. To address the problem associated with achieving priming during the early crop developmental period in FL, rainout shelters along with a linear move irrigation system have been established and will be used in the growing season of 2015. Greenhouse trials similar to those being conducted now in TX are being considered for FL utilizing larger pot sizes in order to evaluate rooting responses under priming. This would be complimentary to the greenhouse trials being conducted in TX at this time. Over the next 6 months, controlled condition experiments in TX and FL investigating the possible hydrotropic responses within those genotypes found to be diverse in their responses in the field are planned. Methodologies discussed and being preliminarily investigated include the use of hydroponics, agar root panels, and MRI imaging to determine not only architectural differences among genotypes but root activity correlated with root presence as well.

Impacts
What was accomplished under these goals? Maintaining sustainable crop production under limited water resources has become the single most important challenge in the U.S. agricultural industry and worldwide. Ultimately, we will evaluate diverse germplasm for the capacity to physiologically acclimate to a water-conservative production system our team has developed called Primed Acclimation (PA). Primed acclimation is the use of limited irrigation application at the beginning of the crop’s development (prior to yield formation) in order to “harden” or make the plant better able to withstand drought stress later in the season. This stress tolerance is acquired through improved root growth, up-regulation of physiological processes, and changes to the plants gene response. In combination, these changes allow the plant to withstand stress better and usually to maintain yield. In addition by using PA, usually at least a 20% savings in water application can occur, thereby conserving water and increasing water-use efficiency of the system. The following project activities were initiated in 2014 at Citra, FL, and Lubbock and Brownfield, TXto address the project objectives: 1) Investigate the physiological and molecular basis of crop response to abiotic stress that occurs in limited water production systems, and the role of stress acclimation in this response. AND 3) use physiological and molecular methods to assist in selection and development of abiotic stress-tolerant peanut cultivars. In Texas: Fifteen peanut genotypes were evaluated at two locations: Brownfield, Texas and at USDA-ARS, Cropping System Research Lab, in Lubbock, Texas. All 15 genotypes were evaluated under two irrigation treatments: full irrigation (100% ET replacement) and reduced irrigation (70% ET replacement). The following measurements were taken through the season: amount of water applied in each irrigation treatment, photosynthetic rate, and SPAD chlorophyll content measurements. The crop will be harvested in October 2014 and dry matter production, pod yield, and grade will be evaluated using standard methods. Tissue samples were also collected for isolating genomic DNA for both control and drought stress treatments and RNA-seq analyses were performed on all genotypes in each treatment. We generated 600 million paired end reads using the HiSeq 2500 sequencer; sequences were assembled for transcriptome analysis. Key outcomes: variability among genotypes in their drought tolerance was documented this season. This information can be utilized as a basis for breeding for improved stress tolerance and to compare with the ranking of acclimation potential among peanut genotypes. Tissue was collected in preparation for comparing gene response under drought response among genotypes and can be linked to physiological responses that were evaluated simultaneously to the tissue collection. We assembled 600 million paired end reads to create the entire transcriptome of peanut. In Florida: Plot Trial 1: Fourteen peanut germplasm lines were grown in the field at the University of Florida, Plant Science Research and Education Unit (PSREU), Citra Florida in 2014. Planting was done on April 22nd 2014 and harvesting on September 11th 2014. The experimental design was a split plot with two levels of irrigation 100% and 60% primed acclimation (60PA). Leaf levelmeasurementsincluded photosynthesis,stomatalconductance,chlorophyll fluorescence, SPAD,relative water content,and specific leaf area. Canopy temperature was taken to monitor plant stress using hand-held infrared thermometers (IRTs). Yield and grade were determined at harvest. There was significant difference in canopy temperature and yieldbetween the 60PA and 100% treatments. Other traits did not vary between treatments. Genotypes with higher canopy temperature had lower yield compared. Key outcomes: variability among genotypes in their ability to acclimate was documented this season. This information can be utilized as a basis for breeding for improved acclimation among peanut genotypes. Further, basic information on the physiological processes involved and the traits that could be utilized for screening genotypes for acclimation potential were determined. Plot Trial 2: A second field study was initiated in 2014 at the University of Florida’s Plant Science Research and Education Unit. Irrigation and peanut genotypes were arranged in a split plot arrangement in a randomized complete block design. Each split plot consisted of six rows (12.2 meters in length with 0.91 meter between rows) of two runner (Arachis hypogea) type, FloRun 107 and TUFRunner 51', and two valencia (Arachis fastigiata) type, New Mexico Valencia C and COC 041 genotypes were planted. The irrigation treatments were the main blocks and consisted of a rain-fed,60% ET replacement, and100% ET replacement. Irrigation scheduling was determined using the University of Florida’s PeanutFARM model (http://agronomy.ifas.ufl.edu/peanutfarm/). Minirhizotron tubes were installed in the rowat a 45° angle to a depth of about 91 cm. Images were recordedusing a BTC 100X camera (Bartz Technology Corporation, Carpimteria, CA). These images were initiated 31 days after planting (DAP) and were repeated every two to three weeks until plant harvest. At 48 DAP planting, infrared temperature (IRT) sensors were installed in every plot and peanut canopy temperatures were used to determine the amount of crop stress time (SmartCrop, Lubbock, TX). Normalized difference vegetative index (NDVI)and leaf area index (LAI) were measured starting at 49 and 45 DAP and continued every two or three weeks during the growing season, respectively. Stomatal conductance (Decagon Devices, Inc., Pullman, WA) was recorded before three irrigation treatments occurring at 71, 94, and 101 DAP. No differences occurred in LAI among peanut genotypes with the different irrigation treatments. A greater yield of 361 kg ha-1 resulted from the reduced (60% of full) irrigation treatment in comparison to the full rate and rain-fed treatment planted to the New Mexico Valencia C cultivar. Yields were similar among the different irrigation treatments for the COC 041 cultivar. 2) Develop straightforward crop management protocols that maximize plant acclimation capacity and effective water use while maintaining economic and environmental sustainability. Two tools are being evaluated to aid in irrigation scheduling and eventual incorporation of PA options for growers: the PeanutFARM website that delivers an irrigation scheduling tool developed by our team; and the SmartCrop infrared temperature crop stress system developed by J. Mahan of our team. The following accomplishments occurred during this reporting period: Irrigation scheduling via PeanutFARM: In trial 2, irrigation scheduling was determined when 50 percent of the plant available water (PAW) was depleted using the University of Florida’s PeanutFARM model (http://agronomy.ifas.ufl.edu/peanutfarm/). The two irrigated treatments were replicated three times and the rain-fed treatment was replicated two times due to space limitations under a linear irrigation system. Canopy Assessment: Canopy status measurements were recorded over the duration of the growing season. At 48 DAP planting, infrared temperature (IRT) sensors were installed in every plot and peanut canopy temperatures were used to determine amount of crop stress time (SmartCrop, Lubbock, TX) (Figure 2). Key outcomes: PeanutFARM irrigation scheduling was shown to be an effective irrigation scheduling tool for the conditions in this trial. The use of PA was easily incorporated into the algorithm of PeanutFARM and this modification can be done easily in the publicly available website version to offer a water conservation option to growers.

Publications

  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Rowland, D., B. Tillman, P. Payton, B. Nguku, C. Vincent, B. Zurweller, B. Schaffer, and S. Byrd. 2014. Taking advantage of physiological priming in crops: breeding for greater acclimation to drought. Invited seminar, Breeding for Tolerance to Water Stress, National Association of Plant Breeders Annual Meeting, Minneapolis, MN 7 August.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Rowland, D. 2014. Breeding for the ability to acclimate to water deficit: physiological mechanisms behind priming for stress. Association for Applied Biologists  Breeding Plants to Cope with Future Climate Change. University of Leeds, Leeds, UK, 16-18 June.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Rowland, D. 2014. Development of sustainable cropping systems utilizing whole plant physiology at the University of Florida. Invited seminar, Harper Adams University, Shropshire, UK, 19 June.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Rowland, D. 2014. Development of sustainable cropping systems utilizing whole plant physiology at the University of Florida. Invited seminar, ISARA, Lyon, FR, 25 June.
  • Type: Other Status: Other Year Published: 2014 Citation: Rowland, D. 2014. Peanut maturity considerations and irrigation. Agronomic In-Service Training, NFREC, Quincy, FL, 21 January.
  • Type: Other Status: Other Year Published: 2014 Citation: Rowland, D. 2014. Drought tolerance of crops under overhead irrigation management. Agricultural Irrigation and 4R Plant Nutrition In-Service Training, Clearwater, FL, 3 June.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2013 Citation: Rowland, D.L., P. Payton, W. Faircloth, S. Byrd, D. Forbes, and B. Speer. 2013. Water conservation strategies utilizing primed acclimation. Invited seminar, ASA/CSSA/SSSA Trisocieties Annual Meeting, Tampa, FL, 3-6 November.