Sub-activity 1. A qualitative molecular diagnostic approach for the detection of several important Fusarium species that attack pea roots (F. solani, F. acuminatum, F. avenaceum and F. redolens) has been standardized. Species-specific probes for additional pathogenic Fusarium spp. isolated from pea root samples, e.g., F. sporotrichiodes, were tested and validated. Primers for Aphanomyes euteiches have been developed, optimized and standardized with successful detection of A. euteiches from roots and stems in preliminary PCR testing. The development of species-specific primers and probes for use in a novel, high-throughput molecular diagnostic system for other pea root pathogens is ongoing.
Sub-activity 2. Four years of field studies identified three field pea cultivars that appear to combined partial resistance to root rot with resistance to seedling blight. When this reaction has been validated, this resistance can be used by growers to reduce yield losses in commercial production.
A multi-year study of two recombinant inbred line populations led to the identification of molecular markers that have been mapped and appear to be closely linked to genes for resistance or tolerance to Aphanomyces root rot. When this work is completed, it will be used by plant breeders to increase the accuracy of selections from crosses with resistant lines and so speed up breeding for resistance to root rot.
Sub-activities 3 and 4. Surveys of pea fields in Alberta and Saskatchewan in 2016 revealed that root rot was widespread across both provinces, and was likely exacerbated by extremely wet conditions in many areas. A. euteiches, F. avenaceum and F. solani were the predominant pathogens detected in roots.
In greenhouse studies where pea plants were inoculated with these three pathogens individually or in mixtures, a mixture of the pathogens always caused more disease compared to an individual pathogen. A risk assessment tool based on quantifying DNA of these three pathogens in soil or previous crop (cereal) stubble samples was tested on samples collected from commercial fields prior to seeding, and compared to root rot severity observed in the same fields in July. F. avenaceum inoculum was primarily present in stubble and detection was low from soil. Detection and quantification of F. solani and A. euteiches was low in soil, and levels of all three pathogens were not well correlated to observed root rot severity. Methods to improve pathogen DNA extraction from soil and to improve sensitivity of DNA detection will be the focus of studies in 2017.
Field trials were also conducted to evaluate cultivar performance, seed treatment and soil- or foliar-applied chemical products at sites in Alberta and Saskatchewan. There was no difference in yield response among treatments for any of the cultivars, seed treatments or other chemical products tested.
Project lead: Dr. Bruce Gossen (306) 385-9409 email@example.com