Assessment and deployment of a new dwarfing gene in red spring wheat

• Term: 3 years, beginning in 2016

• Status: Complete (CLICK HERE to read the performance story)

• Funding Amount: $ 81,941

• Lead Researcher(s): Dr. Pierre Hucl (U of S)

• Funding Partners: Alberta Wheat Commission (AWC), Saskatchewan Ministry of Agriculture - Agriculture Development Fund (ADF)

Project Description

This project focuses on the evaluation of CWRS wheat lines introgressed with dwarfing gene Rht18 from durum in the CDC Bread Wheat Program, for any deleterious effects on agronomic and end-use quality traits and to determine if the Rht 18 gene can be readily deployed in common wheat breeding programs.

The two dwarfing genes deployed in western Canadian wheat cultivars, Rht1 and Rht2 are both semi-recessive and GA-insensitive. Both genes have several drawbacks, including reduced coleoptile lengths, which can result in poor seedling emergence and reduced crop establishment. This is especially a concern when seeding depth is increased due to poor soil moisture conditions near the soil surface, a common occurrence in SK. Both genes have been associated with reduced levels of Type-1 resistance to Fusarium Head Blight (FHB) but increased resistance to spread within the wheat spike (Type 2 resistance). Both genes are also prone to aneuploidy resulting in high frequency of tall variants which can cause problems for pedigree seed growers.

The dwarfing gene “Rht18” is GA-responsive, partially dominant, and has a different physiological dwarfing mechanism than Rht1 and Rht2. The transfer to, and deployment of, Rht18 in common wheat should address the concerns over reduced coleoptile length and the association of GA-sensitivity with increased FHB levels. The objective is to evaluate near-isogenic lines with Rht18 for potential linkage drag and to develop a high throughput KASP marker that is more closely linked to Rht18 than the currently available SSR marker. Once a promising KSAP marker has been identified, it would be strategic to convert FHB-tolerant Rht1 carriers to Rht18. The research findings would result in, reduced costs to Pedigreed wheat seed growers’ due to reduced labour costs for rouging seed fields, potentially reduced FHB infection levels (relative to currently deployed Rht genes) and thus higher grain yields. This will also enable better grades for the harvested crop and better management of shorter, stronger straw cultivars under higher input conditions (environmental and agronomic).