ENHANCEMENT OF CANOLA SEED-GERMINATION AND SEEDLING EMERGENCE AT LOW-TEMPERATURE BY PRIMING

Some seedlots of canola (Brassica napus L. and B. campestris L.) have low percentage germination and poor seedling vigor. The effect of prim ing canola on both seed germination and seedling emergence was investi gated in controlled environment cabinets. Germination was investigated using petri dish assays, whereas emergence was studied by sowing seed s into pots containing a sandy learn soil. Seed germination and seedli ng emergence from soil at 10 degrees C was enhanced for several cultiv ars of both species due to priming. Time to 50% germination and emerge nce was also reduced. A B. campestris cv. Goldrush seedlot, which show ed low germination in preliminary studies, was found to be particularl y responsive to priming and, therefore, was used in subsequent studies to optimize the technique. The optimal priming time varied with tempe rature. Excellent response; occurred with priming for 14 to 16 h at 23 degrees C or 60 h at 10 degrees C. Temperature during priming had lit tle effect on percentage germination, emergence percentage, or time to 50% germination or emergence. Seeds primed for 16 h at 23 degrees C o r for 60 h at 10 degrees C initiated seedling emergence at 10 degrees C 4 d earlier than nonprined seeds. Seedling emergence of primed seeds was 73% compared with 31% for the nonprimed seeds. The benefits of pr iming on both percentage emergence and time to 50% emergence were redu ced if the seeds were primed under anaerobic conditions. In addition, the leachate from primed seeds was inhibitory to both percentage germi nation and time to 50% germination, particularly at 10 degrees C. The results obtained from this study indicate that seed priming has potent ial for improving seed germination anti subsequent seedling establishm ent of canola seedlots with low germination, with low vigor, or when s eeds are planted in cool (< 10 degrees C) soils.