Development of physiological markers for high throughput field screening of drought tolerant wheat lines

Funding Partners: Saskatchewan Ministry of Agriculture – Agriculture Development Fund (ADF)

---

Project Description

This project links biochemistry and physiology to whole plant phenotyping by identifying key biochemical markers for greater drought stress resistance in wheat, which will enable breeders to target specific responses and accelerate the selection of more drought adapted wheat varieties.

Climates are increasingly more extreme and less predictable and this places crops at significant risk, elevating the vulnerability to environmental stress like drought stress which is predicted to impact the prairie region. Therefore, breeding for drought resistance is essential to maintain crop production in unpredictable environmental conditions. The objectives include, developing a rapid non-destructive method to screen drought stress resistant wheat cultivars in a “field-to-lab” approach through hydroponic saline solutions followed by whole plant drought stress experiments; to develop a non-destructive methods using for root mass quantifications using synchrotron technology; to determine non-destructively the role of wax composition or quantity and specialized cells in drought stress resistance through synchrotron technology; to identify the biochemical or physiological marker which best distinguishes resistant from sensitive wheat genotypes, and to develop a simple, cost-effective, fast and high throughput digital root phenotyping and chemo-phenotyping (leaf composition) systems.

For future extension to the field, UV-Visible-NIR spectroscopy and spectral imaging will be investigated for quantifying glaucousness, wax characteristics, and leaf rolling. Leaf surface optical characteristics will be assessed for leaves displaying a range of these characteristics. Based on the comparative analysis between phytotron and field based study, a comprehensive plan will be developed for the field based high throughput phenotyping for screening wheat cultivars for drought tolerance.

Objectives:

1. Nondestructive quantification of root biomass and architecture of drought tolerant and susceptible spring wheat varieties. In a “field-to-lab” based approach, we will pre-screening a of large number of varieties contrasting for drought stress contrasting varieties as previously identified under field conditions for root growth. and Root-related traits will be executed quanitified by growing plants hydroponically and by applying saline stress. A Sub-set of tolerant and susceptible varieties elected from the pre-screening study will be then be used for more detailed study by growing plants grown in soil and performing phase contrast X-ray imaging (PCI) method will be used to continuously monitor the root growth and root biomass of spring wheat in-situ.
2. Nondestructive determination of the epicuticular wax thickness and wax composition, and bulliform cells. Specialized cell types and wax profiles of contrasting cultivars, and the effect of drought stress on wax profile will be non-destructively evaluated. The mid infrared (mid-IR) and attenuated total internal reflection (ATR) method will be used to measure the epicuticular wax thickness and to determine the wax types from the adaxial and abaxial sides of leaves.
3. Determine the role of essential ions to drought tolerance in spring wheat varieties. The role of essential ions in the leaves to drought tolerance in spring wheat will be determined by measuring total calcium to potassium present in the leaves. The hard X-ray spectroscopy method will be used to quantify the amount of calcium and potassium from the leaves of drought tolerant and susceptible spring wheat.
4. Identify phenotyping methods for high throughput screening of drought tolerant wheat varieties. Based on outcomes of objectives 1, 2 and 3, best methods to scale up for digital field high throughput phenotyping suitable for screening genotypes for breeding programs will be identified, in a “lab-back-to-field” approach.