Work

Long hypocotyls facilitate deeper sowing to improve canola establishment in a warming climate

Year: 2026

Type: article

Abstract: KEY MESSAGE: Deeper sowing of canola into cooler, moist soil could improve crop establishment in stressful conditions. We demonstrate cultivars with long hypocotyls emerge better from deeper sowing than short hypocotyl cultivars. Poor seedling establishment is a major constraint to canola (Brassica napus L.) productivity globally. Optimum seeding depths are commonly 1-2 cm under favourable soil moisture and temperature conditions., However, drying autumn conditions with climate change coupled with increasing farm size often results in canola sown earlier when the soil surface is hot and dry. Deeper sowing (> 3-4 cm) into stored water and more stable temperature allows for timely establishment of early sown crops. Under favourable moisture and temperature conditions, current cultivars establish well at shallow sowing depths but emerge poorly when sown deeper. This study investigated the potential to breed canola cultivars with longer hypocotyls to improve emergence from deep sowing as a strategy to adapt to earlier sowing under climate change - a concept demonstrated successfully with longer coleoptile wheat. A diverse panel of 255 open-pollinated accessions was phenotyped using high-throughput laboratory assays for hypocotyl length and cross-sectional area. Genome-wide association analysis revealed hypocotyl length was under polygenic control, and several significant marker-trait associations were identified. Emergence was validated in multiple field environments with both conventional (2 cm) and deeper (5 cm) sowing. Increased hypocotyl length was strongly associated with improved emergence from deep sowing, supporting its value as a breeding target to improve canola establishment under increasingly variable and challenging growing conditions.

Source: Theoretical and Applied Genetics

DOI: 10.1007/s00122-026-05396-2