EFFECT OF LOW-TEMPERATURE AND SEEDING DEPTH ON THE GERMINATION AND EMERGENCE OF 7 FLAX (LINUM-USITATISSIMUM L) CULTIVARS

Cool, moist soils combined with deep seeding can have a dramatic negat ive effect on percent emergence and the time to emergence of flax seed lings. The effects of temperature (over a range of 5-15 degrees C) on seed germination, and seedling emergence from a sowing depth of 20 and 40 mm, were determined for seven cultivars of flax. Temperature had n o effect on percent germination; however, the time for 50% of the seed s to germinate at 5 degrees C was on average 160 h compared with 30 h at 15 degrees C. The time for 50% of the seeds to germinate at tempera tures less than 8 degrees C was the least for Andro and Vimy and the g reatest for Dufferin, McGregor and Norlin. Temperatures less than 10 d egrees C had a dramatic effect on seedling emergence from both seeding depths. On average, fewer seedlings emerged from the 40-mm seeding de pth than from the 20-mm seeding depth. The time for 50% seedling emerg ence at 5 degrees C was on average 450 h for seeds sown 20 mm deep and 600 h for seeds sown 40 mm deep. In contrast at 15 degrees C, 50% of the seedlings for all seven cultivars emerged after 150 h from 20 mm a nd 180 h from 40 mm. At the cooler temperatures and 40 mm seeding dept h, Vimy and Andro had the highest emergence rates, while Dufferin and Norlin had lowest emergence rates. This study demonstrates the importa nce of seeding depths when seeding into cool soils. Also genotypes suc h as Andro and Vimy are more likely to provide uniform stands when soi ls are cool and moist and when flax is seeded deep.