Enhancement of Canola Seed Germination and Seedling Emergence at Low Temperature by Priming

Abstract

Some seedlots of canola (Brassica napus L. and B. campestris L.) have low percentage germination and poor seedling vigor. The effect of priming canola on both seed germination and seedling emergence was investigated in controlled environment cabinets. Germination was investigated using petri dish assays, whereas emergence was studied by sowing seeds into pots containing a sandy loam soil. Seed germination and seedling emergence from soil at 10°C was enhanced for several cultivars of both species due to priming. Time to 50% germination and emergence was also reduced. A B. campestris cv. Goldrush seedlot, which showed low germination in preliminary studies, was found to be particularly responsive to priming and, therefore, was used in subsequent studies to optimize the technique. The optimal priming time varied with temperature. Excellent responses occurred with priming for 14 to 16 h at 23°C or 60 h at 10°C. Temperature during priming had little effect on percentage germination, emergence percentage, or time to 50% germination or emergence. Seeds primed for 16 h at 23°C or for 60 h at 10°C initiated seedling emergence at 10°C 4 d earlier than nonprimed seeds. Seedling emergence of primed seeds was 73% compared with 31% for the nonprimed seeds. The benefits of priming on both percentage emergence and time to 50% emergence were reduced if the seeds were primed under anaerobic conditions. In addition, the leachate from primed seeds was inhibitory to both percentage germination and time to 50% germination, particularly at 10°C. The results obtained from this study indicate that seed priming has potential for improving seed germination and subsequent seedling establishment of canola seedlots with low germination, with low vigor, or when seeds are planted in cool (<10°C) soils.