Project Overview & Scope

Standards and Methods

Click here to download Genomes to Fields phenotyping handbook guidelines

Project Summary Table

  2014 2015 2016 2017 2018
No. of experiments 23 28 40 43 40
No. of unique locations 19 24 34 38 31
No. of states/provinces 13 16 19 23 22
No. of Principal Investigators 19 25 29 32 28
No. of plots 12,678 13,650 19,360 21,186 27,298
No. of unique inbreds 380 553 313 295 295
Ex-PVP 25 55 76 83 83
Biparental derived 302 301 44 42 42
Diverse 53 197 193 170 170

2014 Experiment

The 2014 GxE Experiment consisted of a large hybrid trialing effort and a smaller inbred trialing effort. For our first year of field experiments, 25 principal investigators in 14 states and one Canadian province tested over 900 hybrids, deployed as groups of 250 hybrids with two replications at each location. With 23 participating locations, a total of 12,678 plots were grown. As part of the 250 hybrids, a set of 10 diverse hybrids was tested across all locations; other hybrids were selected based on reasonable maturity for specific locations. Except for the set of common hybrids, testers included LH198, LH195, LH185, CG102 and PB80. In addition, 31 inbred lines were replicated 2 to 12 times over 15 locations for a total of 1,598 plots. Inbred lines tested in 2014 include recombinant inbred lines (RILs), Expired Plant Variety Protection (exPVP) inbreds and lines from collaborator breeding programs.

2015 Experiment

For the second year of evaluations, the GxE experiment expanded to include Ohio, Kansas, and South Dakota, for a total of 17 states and one Canadian province overseen by 28 principal investigators. Data were collected from 28 hybrid experiments and 25 inbred experiments in 27 unique locations. For the hybrid experiment, effort was made to maintain continuity with 2014 while expanding the diversity of materials included in 2015 experiments and increasing overlap among locations. Most locations grew 500 hybrid plots, with a total of 13,650 plots. The design was modified from 2014 to increase the number of common hybrids to 45 hybrids in all locations plus 15 regional hybrid checks in Northern, Central, and Southern regions, each replicated twice per experiment for 120 entries. The remaining 380 hybrids were mostly unreplicated, except for the most northern and most southern locations where additional hybrids were included with two replications. Each hybrid was included in at least 8 locations and selected with consideration to adaptation, diversity, and replication of alleles. Except for the set of common hybrids, testers included PHB47, PHZ51, LH82 and LH195. For the inbred experiments, 32 inbred lines were replicated twice over 17 locations in 25 experiments for a total of 1,600 plots.

2016 Experiment

In 2016, the project continued to expand to Arkansas, Michigan, and South Carolina. In total, 40 hybrid experiments across 34 unique locations in 19 states and one Canadian province were overseen by 29 principal investigators. Significant growth in both the number of experiments, and the addition of several “mega locations” in Iowa, Wisconsin, and Missouri, resulted in 19,360 plots planted in 2016. New in 2016, the hybrid experiment was organized into five broad sub-experiments, summarized below:

  1. Ex-PVP Factorial ("Design 2") Experiment: Planned ex-PVP diallels integrated with genomic prediction based on ex-PVP-derived progeny. Three sets of materials selected for appropriate maturity were planted in 28 locations. Led by Jode Edwards (USDA ARS), Elizabeth Lee (Guelph), and Martin Bohn (University of Illinois Urbana-Champaign).
  2. Stiff Stalk GxE: Founder lines, public early releases, and ex-PVP lines, which represent a span of selection pressure, crossed by inbred line 3IIH6. The Stiff Stalk Set was planted in 17 locations. Led by Natalia de Leon and Shawn Kaeppler (University of Wisonsin-Madison).
  3. Near-Isogenic Lines Experiment: Teosintes introgressions; B73/Mo17 near-isogenic lines (NILs). The NILs experiment was planted in 17 locations. Led by Sherry Flint-Garcia (USDA-ARS) and Candice Hirsch (University of Minnesota).
  4. Germplasm Enhancement of Maize (GEM): A highly diverse set of materials containing un-adapted, exotic germplasm to enhance genetic diversity and trait performance, and to minimize risks to production. The GEM lines were crossed with inbred line LH195 and were planted in 17 locations.
  5. Common Hybrid Checks: A set of 50 common check hybrids and five local checks were planted in all locations. Two smaller sets of regional common hybrids (15 early and 5 late) were planted in locations based on maturity. Hybrid checks were selected for diversity and continuity with 2014-2015 experiments.

2017 Experiment

In 2017, the project will progress further with the addition of three new principal investigators in Arizona, Colorado, and Mississippi. As a result, over 20,000 plots comprising 41 experiments are being grown by 30 investigators in 37 unique locations.The experiment in 2017 will replicate the five broad sub-experiments planted in 2016, with the addition of a sixth sub-experiment headed by Randy Wisser (University of Delawaree).

2018 Experiment

For planting season 2018, the experiment utilized genetic materials with a relatively narrow maturity window, across all locations; thus, resulting in reduced impact flowering time on results, presenting more uniform data, and simplifying plot management for the collaborators.

Experimental Design:

Description of Randomization:

  1. Hybrids were grouped into four categories based on seed availability.
    1. Hybrids with 350 - 660 seeds = Group 4: tested in one rep at four randomly chosen environments.
    2. Hybrids with 660 - 1000 seeds = Group 8: tested in one rep at 8 randomly chosen environments.
    3. Hybrids with 100 – 1900 seeds = Group 24: tested in one rep at all environments.
  2. Within a site, there are two replicates 'reps'. Any hybrids tested twice at a site appear once in each rep. So, for the subset of replicated hybrids, the reps are RCBDs. For unreplicated hybrids, hybrids where randomly assigned with stratification to one of the two reps. Stratification ensured nearly equal proportional representation of families in each rep, and about equal numbers of hybrids in each rep
  3. Hybrids were grouped by families within reps (this grouping is labeled as 'block' in the design). Family order was randomized for each rep.
  4. Check hybrids were randomly assigned to plots within reps, without regard to the 'block' structure.



2019 Experiment

In 2019, further continue testing with the same genetic material as in 2018. A new international collaborator joined the initiative, Georg-August-University from Göttingen, Germany. As a result, over 27,000 plots were evaluated across 31 unique locations. The experiment in 2019 used the same experimental design and testers adapted to each location.

2020 Experiment

For the 2020 experiments, 3 testers were decided to be used to have more closely adapted material to each location. For the first time select locations tested HIPS (High Intensity Phenotyping Site) plots with novel phenotyping methods and tools. The initiative also began to use UAVs (unmanned aerial vehicles) to measure specific traits in thousands of plots.

Experimental Design:

Description of Randomization:

  1. Each trial is arranged in two replications (500 plots total). For the purposes of blocking in the field, the primary division is by replication (1 or 2) then by tester (PHP02, PHK76, PHZ51) if there are multiple testers. Most locations only included one tester.
  2. Additional external blocks were created upon request for external Yellow Stripe replications to facilitate sampling or additional phenotyping. External experiments with 2 replications of 25 entries were also created upon request for Hybrid HIPS and Inbreed HIPS.
  3. The objective of the experimental design was to balance the need for within-site replication against the overall goal of the GxE project to test as many different hybrids as possible at each trial site. If a location has hybrids with multiple testers, an equal amount of the plots were assigned to each tester as separate experiments.
  4. Within an experiment there are two replications and each replication will have one plot of each of the core check hybrids (YS-Hybrids) based on seed availability.
  5. Most hybrid trials are arranged in two-row plots, 20' long with 30-72" alleys between plots.



Hybrids Used

Download the full list of hybirds used in 2014, 2015, 2016, 2017, and 2018

DNA sequence data from 858 inbred parental lines was derived using Genotyping by Sequencing (GBS) techniques. An additional 206 inbred lines will be sequenced in spring 2016 to complete the set of parental inbreds for all hybrids included in experiments in 2014-2016.

Environmental Data Collected

Each experiment is furnished with a WatchDog 2700 Weather Station by Spectrum Technologies, Inc. The weather stations record air temperature, humidity, solar radiation, rainfall, wind speed and direction, soil temperature, and soil moisture every 30 minutes for the duration of the growing season. In addition, collaborators submit soil samples for basic nutrient and texture analysis to a central soil testing lab.

Phenotypic Traits

The following table summarizes phenotypic traits measured by each GxE experiment cooperator at each location.

Trait Abbrv. Unit Timing Description/Procedure
Green Snap (optional) GSP Count and date of causal event [DD/MM/YY] Before flowering Number of plants broken between ground level and top ear node before flowering
Anthesis DMF Date [DD/MM/YY] At flowering Days between planting and 50% of plants of a plot exhibit anther exertion on more than half of the main tassel spike
Silking DFF Date [DD/MM/YY] At flowering Days between planting and 50% of plants of a plot show silk emergence
Ear Height EHT Centimeter [cm] and date measured [DD/MM/YY] After flowering Placing measuring stick on ground next to the root crown, "ear height" is measured at the primary ear bearing node
Plant Height PHT Centimeter [cm] and date measured [DD/MM/YY After flowering Measure the distance between the base of a plant and the ligule of the flag leaf
Root Lodging RLD Count before harvest Number of plants that show root lodging per plot, i.e., those stems that lean substantially to one side (≥15% from vertical). Count includes "goosenecked" plants that have "straightened up" after becoming lodged earlier in the season
Stalk Lodging SLD Count Before harvest Number of plants broken between ground level and top ear node at harvest
Stand Count STC Count At harvest Number of plants per plot at harvest.
Plot Weight PWT lbs At harvest Shelled grain weight per plot
Grain Moisture GMT Percent [%] At harvest Water content in grain at harvest
Test Weight TWT lbs/bu At harvest Shelled grain weight per bushel