Field evaluation of ascorbic acid seed priming on growth, physiology, yield, and nutritional quality of broccoli (Brassica oleracea L. var. italica ‘Gypsy’)

Abstract

Seed priming with ascorbic acid (AsA) has been widely recognized for enhancing early plant development; however, its effectiveness in improving growth, physiology, yield, and nutritional quality of broccoli under field conditions remains limited. This two-year field study evaluated the effects of AsA seed priming on broccoli under Atlantic Canada soil conditions using a randomized complete block design across two field sites. Four treatments were assessed: non-primed control, water-primed (0 mgL-1), and AsA-primed seeds at 1 mgL-1 and 10 mgL-1. AsA priming significantly (p < 0.05) enhanced plant height, canopy length, stem girth, and leaf area, with the greatest improvements observed at 10 mgL-1, resulting in increases of 17.4%, 19.7%, 51.7%, and 69.4%, respectively, compared to the control. Net photosynthesis, stomatal conductance, transpiration, and chlorophyll index, were also significantly improved (p < 0.001). Biochemical analysis showed significant increases (p < 0.05) in chlorophyll a and carotenoid content at 10 mgL-1. Meanwhile phenolics, flavonoids, and most nutrients were not significantly affected (p ≥ 0.05), except for a slight but significant (p < 0.05) reduction in phosphorus concentration at 10 mgL-1. Yield components were significantly (p < 0.05) improved by AsA priming, with 10 mgL-1 increasing primary yield by 38.4% and secondary yield by 80.4%, whereas 1 mgL-1 significantly (p < 0.05) increased the number of secondary heads per plant by 15.3% compared with the control. Overall, AsA seed priming enhanced growth, physiological performance, and yield without compromising nutritional quality, demonstrating its potential as a practical and sustainable approach to improve broccoli production under field conditions.