Assessing Ontario dry bean germplasm for nitrogen fixing capacity

Lead Applicant: Karl Peter Pauls

Research Priority: Competitive Production Systems 

Program Type: Tier 1

Funding Cycle: 2023/2024

Research Centre: Ontario Crops Research Centre – Elora

Research Summary: Ontario dry bean growers add nitrogen fertilizer, rather than exploiting symbiotic bacteria that utilize atmospheric nitrogen for biological N-fixation (BNF). A previous study showed that BNF capacity varies tremendously among Pan-American bean varieties/genotypes, supplying 30-70% of their nitrogen needs. Some information about BNF-promoting bean genetic loci exists, but a systematic screen of the most important germplasm for breeding varieties suitable for Ontario has not been conducted, partly because the assay is complicated/expensive. For this project, we will develop a rapid leaf-punch based assay (GlnLux) for screening beans for BNF capacity and identify BNF-associated molecular markers to screen/improve Ontario bean germplasm. We will also improve N-fixing bacterial inoculant by identifying rhizobia and nodule-helper-microbes from the best, widely grown N-fixing Ontario varieties, then breed for stable N-fixation across Ontario soils/environments in the presence of (50%-reduced) N-fertilizer which suppresses BNF. Improved bean varieties/bacteria will encourage growers to reduce N-fertilizer use, therefore, reducing costs and greenhouse gas emissions associated with N-fertilization.