John L. Snider Third Year Review Crop Physiologist University of Georgia Department of Crop and Soil Sciences
Responsibilities Teaching: 15% Appointment Advanced Crop Production: CRSS 8050 Crop Physiology: CRSS 4450/6650 Graduate Student Advising Research: 85% Appointment Drought Stress Irrigation Management Heat Stress Drought and Heat Tolerance Screening Seedling Vigor
Teaching
Crop Physiology
PeanutTobacco Cotton Corn Advanced Crop Production
Graduate Student Advisement Graduate Student Major Advisor Calvin Meeks to Present. PhD Daryl Chastain to Present. PhD Graduate Student Advisory Committee Member Seth Byrd to Present. PhD Harold Owiti to Present. MS Calvin Meeks to MS
RESEARCH FOCUS 1 Drought Stress Physiology & Irrigation Management
2012 Drought Stress Study
Location Stripling Irrigation Research Park: Camilla, GA Three Cultivars DP 0912 B2RF, DP 1050 B2RF, PHY 499 WRF Two Irrigation Treatments Dryland 100% Checkbook Statistical Design/Analysis Split-plot, RCBD, n=4, 3 Mixed Effects ANOVA 100 % checkbook irrigation amounts Growth Stagecm/week Pre-Bloom2.54 1st Bloom (week 1)2.54 Week Week Week Week Week Week Week 82.54
Temperature: T air T leaf Water Status: Ψ PD Ψ MD PSII: F v /F m Φ PSII ETR Gas Exchange: P N P G R D g s E
Summary MeasurementTrend Photosynthesis↓ R D /P G ↑ gs, E↓ Canopy Temperature↑ PS II = Cultivar= Lint Yield↓ Arrows indicate direction of effect for dryland relative to 100% checkbook. How do underlying mechanisms interact to inhibit net photosynthesis and drive yield loss? J. Plant Physiol., 2014 J. Agron. Crop Sci., 2014
Plant-Based Irrigation Scheduling
Predawn Water Potential for Scheduling Irrigation Location Stripling Irrigation Research Park: Camilla, GA Two Cultivars FM 1944 PHY 499 Five Irrigation Treatments 100% Checkbook -0.5 Mpa -0.7 Mpa -0.9MPa Dryland Design RCBD n = 4 Sampling Leaf sampled from 4 th main-stem node below the apical meristem three days per week.
Rainfall and Irrigation: 2013 & 2014 All data are in cm. Treatment Irrigation 2013 Irrigation 2014 Rainfall 2013 Rainfall 2014 Total 2013 Total 2014 Checkbook MPa MPa MPa Dryland
Predawn Water Potential (Ψ PD ) 2013 2014
Season-Average Predawn Water Potential 2013 2014
Yield x Average Ψ PD Yield & WUE optimized
T C - T a Well-Watered Baseline Can Use This Model to Calculate Crop Water Stress Index
T C -Derived Crop Water Stress Index
T C -Derived Crop Water Stress Index
Yield x CWSI
RESEARCH FOCUS 2 Heat Stress Physiology & Drought/Heat Tolerance Screening
Assessing Heat Tolerance
T 15 as a Common Heat Tolerance Threshold
Overview of Heat Tolerance Work Seasonal and Genotypic Differences (J. Plant Physiol., 2013) Stage of Plant Development (J. Agron. Crop Sci., in press) Thermotolerance and yield stability Leaf Development
RESEARCH FOCUS 3 Seedling Vigor
Multi-Location Seedling Vigor Trial Current work focusing on fatty acid saturation & seedling response to temperature. J. Cotton Sci. 2014
QUESTIONS?