Intercropping Chickpea with Flax in Saskatchewan, Canada, Reduces Ascochyta Blight

ABSTRACT Chickpea is a nutritious crop grown in drier parts of Saskatchewan. The disease Ascochyta blight, caused by Ascochyta rabiei , makes production risky. Small plot trials at four Saskatchewan locations from 2018 to 2022 aimed to test the hypothesis that intercropping chickpea with flax reduces Ascochyta blight. Three factors were tested: flax seeding rate, row arrangement (both crops in the same rows vs. in alternating rows) and nitrogen fertilizer application. Intercropping with flax reduced disease when all site‐years were considered. The site‐years differed in disease, ranging from < 1 on a 0–9 scale to 4.0, considered moderate disease. At the one site‐year where seed infection was seen, higher flax seeding rates reduced the fraction of infected seeds. Nitrogen fertilization resulted in more severe disease overall; the results differed between site‐years. Row arrangement had no overall effect on disease but had an impact on disease severity at some site‐years. Higher flax seeding rates resulted in the lowest chickpea pods being higher above the ground and fewer lateral branches. Nitrogen application had the opposite impact. Mean canopy relative humidity and temperature in the 5 days before the highest disease was recorded were impacted by intercropping, as compared to monocropping, at only one and two site‐years, respectively. Changes in canopy microclimate may contribute to disease reduction in chickpea/flax intercropping under high relative humidity. Changes in chickpea morphology, such as pod height and lateral branches, may also play a role. Intercropping flax with chickpea has potential for Ascochyta blight management in Saskatchewan. Additional research under wetter conditions with more severe Ascochyta blight is needed.