Root the Future: Defying Climate Stress with Heritage Winter Wheat Genetics

Transcript:

Hi, I'm Ahilesh, and this is my project, Root of the Future. Rising temperatures and droughts threaten global food security. Winter wheat avoids summer heat, but its survival depends on strong fall root establishment. I hypothesize that modern breeding focused on above-ground yield has inadvertently weakened these crucial root systems. I tested three varieties, a modern Canadian cultivar developed in Lethbridge, Alberta, a 126-year-old heritage variety called Karkov, and a wild Japanese landrace. I exposed them to cold and induced drought stress, then analyzed their architecture over a six-day period using a rhizovision explorer. The results were striking. Karkov outperformed the modern cultivar in every metric, producing 62% more total root length. Even the wild landrace showed superior resilience under combined stress.This proves we have traded root robustness for yield. To protect future crops, we must look and reintroduce these forgotten heritage genetics. Thank you.

Why?

Growing up in Saskatchewan, I watched the province change. The summers got hotter, the wildfire smoke thicker, the growing seasons shorter. My family immigrated from South India, where food insecurity is not abstract. Watching the same pressures arrive in Canada made me wonder: what happens to our wheat when the climate becomes as unpredictable as the monsoon?

Problem: Compressed Growing Season/Food Security: Global temperatures are rising at an unprecedented rate; 2026 is projected to be the hottest summer in Canadian history (Canada, 2026). This has produced intensifying drought, wildfires, and a compressed growing season; threatening food security as global wheat demand is projected to increase 60% by 2050 (Gandaria, 2020).

Winter Wheat avoids peak summer stress through fall planting and an early spring harvest, contingent on three factors (Ober et al., 2021):

Root systems must develop deep, branched architecture before Winter.

Root systems largely determine resilience in the Spring season.

Modern breeding has focused on above-ground growth, potentially at the expense of root systems.

Research Question: Do heritage winter wheat varieties demonstrate greater root system resilience under combined osmotic and cold stress compared to modern cultivars?

Approach: I chose three cultivars, the wild landrace (Abura Komugi), 1900 heritage variety (Karkov), and Canada's modern domestic cultivar (AAC Gateway). These cultivars represent a holistic arc of wheat development. They were grown under replicated Canadian fall conditions osmotic and cold stress, then analyzed using RhizoVision Explorer.

Reintroducing heritage root traits into modern cultivars could produce varieties equipped for increasingly harsh conditions.

Background Research: Literature was reviewed on osmotic stress physiology in T. aestivum, root system architecture methodology, and winter wheat agronomy. [Tanino, K. K. (2016). Development of physiological markers for high‑throughput field screening of drought‑tolerant wheat lines (Agriculture Development Fund and SaskWheat Project Final Report No. 20160229)].

Supplies:

· Seeds (Karkov, Aburka Komugi, AAC Gateway)

· 70% ethanol

· 3% bleach

· Petri plates

· Agar powder

· NaCl

· Distilled water

· Sterile distilled water

· Scale

· Laminar flow hood

· Autoclave

· Autoclavable jars and containers

· Growth chambers

Media Preparation: Agar media was prepared at 9 g/L in distilled water. NaCl was calculated stoichiometrically: 2.62 g/600 mL (75 mM) and 5.25 g/600 mL (150 mM). These sodium levels mimicked historic prairie drought from Agriculture Canada. Media was autoclaved (121°C, 20 min) and cooled to ~50°C before pouring to sterilize. Nutrients were omitted due to the timeframe and to reduce risk of agar contamination.

Plate Sterilization: Large square Polystyrene petri plates (245 × 245 mm, Corning) were sterilized under a laminar flow hood with 70% ethanol, filled, solidified (~5 min), and sealed with Parafilm until plating.

Seed Sterilization: Seeds were sterilized following ActinoBase protocol: 70% ethanol (30 sec), 3% bleach (10 min), three sterile water rinses, then germinated on sterile filter paper in the dark until radicle emergence (~2 days).

Plating: 10 germinated seeds per genotype were evenly spaced and pressed into each plate, producing 36 plates total (3 varieties × 3 NaCl levels × 2 temperatures × 2 replicates).

Growth Conditions: Plates were kept at 15°C - Control (Thermo Scientific Precision Model 818) or 7.5°C - Cold (Powers Scientific Diurnal Growth Chamber) for 6 days.

Imaging/Analysis: Plates were scanned daily on an Epson LA2400. RhizoVision Explorer (v2.0.3) yielded branching frequency, total root length, surface area, and average diameter per treatment group.

LEGEND: (KA = Karkov, AK = Abura Komugi, AG = AAC Gateway)

Constants/Variables:

Constants: Agar volume per plate (150 mL); scanner resolution (600 DPI); RhizoVision Explorer settings (Broken Roots mode, pruning threshold = 5).

Independent: Varieties (T. aestivum; Abura Komugi - Landrace, Karkov - Old, AAC Gateway - Modern); osmotic stress (0, 75, 150 mM NaCl); temperature (7.5°C, 15°C).

Dependent: Total root length (mm), surface area (mm²), volume (mm³), branching frequency (mm⁻¹), average diameter (mm), root tip count.

Findings:

Karkov consistently produced the greatest total root length, surface area, volume, branch points, and root tips across every day and every treatment combination, except under the most extreme combined stress (150 mM NaCl at 7.5°C), where growth metrics converged for all cultivars. By Day 6, Karkov reached a mean total root length of 383.2 mm, compared to 268.5 mm for Abura Komugi and 236.6 mm for AAC Gateway which is a 44% and 62% advantage respectively (Figure 2).

Notably, the wild landrace Abura Komugi outperformed the modern cultivar AAC Gateway in most significant metrics, despite having no history of formal breeding selection.

Temperature: Temperature was the dominant factor suppressing root growth. At 15°C, all three varieties showed rapid and consistent root growth throughout the experiment. At 7.5°C, growth was severely stunted across all varieties from Day 1. By Day 6, the best performing variety (Karkov) grown at 15°C reached a mean of 583.1 mm, while the same variety under cold conditions grew only 183.2 mm, a 218% reduction (Figure 3).

Osmotic Stress: NaCl concentration had a smaller, yet meaningful suppressive effect. The 75 mM and 150 mM treatments correspond to soil water potentials of approximately −3.5 bar and −7.0 bar respectively, calculated using the van't Hoff equation (Ψs = −iRCT). For context, −3.5 bar falls within the range of severe drought stress for a typical prairie (75 mM NaCl), while −7.0 bar (150 mM NaCl) represents conditions approaching the upper limits of crop survival. Under maximum stress (150 mM, 7.5°C), all three varieties converged to similar root lengths by Day 6, suggesting Karkov's genetic advantage is most expressed under moderate stress and diminishes under extreme combined conditions (Figure 4).

Root Tips: Root tip count increased consistently across all three varieties over the six-day period. Karkov produced the greatest number of root tips at day 6 reaching a mean of 70 under control temperature conditions, compared to 67 for Abura Komugi and 58 for AAC Gateway (Figure 5). This trend is consistent with the total root length data. Karkov not only builds longer roots but generates more growing points, suggesting a fundamentally more productive root development system than the modern cultivar and landrace.

[Figure 1: Total Root Length Over Time] [Figure 2: Total Root Length Growth Day 1-6 (%)] [Figure 3: Effect of Temperature on Total Root Length] [Figure 4: Effect of NaCl (Drought Stress) on Root Growth][Figure 5: Number of Root Tips at Control Temperature]

Implication:

Karkov, the 126-year-old variety, outperformed Canada's own domestic cultivar AAC Gateway in almost all root architecture metrics, across every day, under every treatment condition tested. By Day 6, Karkov produced 62% more total root length than AAC Gateway. This was not expected.

Abura Komugi, a wild Japanese landrace with no formal breeding history, also outperformed AAC Gateway (Figure 1). Two varieties from completely different ecosystems both surpassed the modern cultivar suggests that something was lost in modern breeding processes.

The likely explanation is economic. Breeders select for what is visible, easily measurable, and profitable; grain yield, plant height, and disease resistance. Root systems are underground, slow to measure, and are largely ignored in comparison. Decades of this screening may have accumulated into a measurable deficit in modern root architecture.

This matters because roots are not a secondary trait. They determine water uptake, drought resilience, and fall establishment survival, precisely traits that will be needed as climate change takes hold globally influencing weather patterns and growing seasons.

In conclusion, it is likely that the genetics needed to build more resilient winter wheat already exist. However, are sitting in old seed collections or in the wild, largely overlooked because root systems are invisible and are not largely screened in the modern breeding process. Although these root traits are not a top priority currently, with Climate Change taking hold perhaps it is time to revisit these older cultivars.

What's Next?

Accuracy: Increasing replication beyond two replicates per treatment, extending imaging beyond six days, and using identical growth chambers would enhance the accuracy of this expiriment.

Bigger Picture: Screening genotypes from additional countries/breeding programs to clarify whether Karkov's advantage reflects a broader pattern in pre-modern wheat genetics or is variety-specific.

Pre Processing: Improved Machine Learning segmentation trained on wheat seedling images in agar to reduce false detections from agar cracking/seed tissue in Rhizovision.

Application: Using these findings to reincorporate heritage root genetics such as Karkov's into modern cultivars for a combination of root resiliance and yield.

Institutions

University of Saskatchewan, College of Agriculture and Bioresources

Agriculture and Agri-Food Canada, Saskatoon

Supervisor

Karen Tanino, Ph.D., Professor, Plant Sciences Department

Mentor

Julie Clarke, Masters Student, Plant Sciences Department

Acknowledgements

I would like to thank my supervisor, Karen Tanino, for her generous support and regular feedback throughout this project, as well as for providing access to lab materials and space. Thank you to Julie Clarke for nearly daily mentorship, including hands-on training in media preparation, plant growth, and data analysis; this project would not have been possible without her guidance. I would also like to thank Colleen Nielson at Agriculture and Agri-Food Canada for providing the wheat cultivars used in this study. Thank you!

Additionally thank you to all the staff and sponsors for the Saskatoon Regional Science Fair for hosting and making such a wonderful event possible!

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