Canola Seed Survival Over Winter in the Field in Alaska

109

. 2000. Alternative seeding dates (fall and April) affect Brassica napus canola yield and quality. Can. J. Plant Sci. 80: [713][714][715][716][717][718][719]. Brassica napus L. canola production on the Canadian prairies often is limited by hot, dry growing conditions in early July and a short growing season. Brassica napus canola seeded in the fall just prior to freeze-up or in the early spring as soon as fields are passable may allow canola to avoid these adverse conditions. Our objective was to determine if late October (fall), or mid-to late April (April) seeding dates improve canola yield and quality relative to a mid-May (15 to 20 May) seeding date. Plant density and height, phenological development, seed yield, seed weight and seed oil content were assessed in plots sown to herbicide-tolerant B. napus canola at three seeding dates on five fallow sites and three stubble sites at Scott, SK, from 1994 to 1998. A thinner plant stand occurred for the fall compared with spring seeding dates; however, this difference rarely corresponded with less canola yield. Fifty percent flowering occurred 20 d earlier (June rather than July), reproductive growth (50% flowering to maturity) was 10 d longer, plants were 23 (fall) or 8 (April) cm shorter, and maturity occurred 13 d earlier when canola was seeded in the fall and April compared with mid-May seeding. Canola seed yield was 38% greater when seeded on the alternative dates rather than the more traditional mid-May seeding date. The yield advantage for alternative seeding dates was greater and more consistent on stubble than on fallow likely because of lack of soil crusting and temperature and wind protection from stubble. The response of seed weight to seeding date was similar to that for seed yield, indicating that a portion of the positive yield response to alternative seeding dates was associated with larger seed size. Oil content also was greater for the fall and April compared with mid-May seeding dates, but the improvement was smaller (6%) than that for seed yield. Fall-and April-seeded canola tolerated spring frosts and avoided adversely hot, dry weather during the flowering period, thus improving canola seed yield and quality. Alternative seeding dates provide canola producers in semi-arid regions with a sustainable option to diversify their cropping systems.Key words: Seeding date, dormant, stubble, fallow, herbicide tolerant, alternative cropping practice.Kirkland, K. J. et Johnson, E. N. 2000. Effets de la date de semis, automne ou avril, sur le rendement et la qualité de Brassica napus (type canola). Can. J. Plant Sci. 80: 713-719. La production du colza (Brassica napus L.) de type canola dans les prairies canadiennes est souvent plafonnée par le temps chaud et sec qui sévit en début de juillet et par la longueur insuffisante de la saison de végétation. Le semis réalisé en automne, juste avant l'installation du gel ou en début de printemps dès que les champs sont praticables permettrait éventuellement d'éviter ces mauvaises conditions. Dans cette optique, n...

Section: Emergence and Seedling Densitymentioning

confidence: 99%

Alternative seeding dates (fall and April) affect Brassica napus canola yield and quality

Kirkland¹,

Johnson²

2000

109

“…There was also a year effect; seed derived from the 1998 fall harvest had higher emergence than seed derived from the 1997 fall harvest for all site-years. Sparrow et al (1990) also noted that 1-yr-old canola seed did not over-winter in Alaska as well as recently harvested seed. This may be due in part to aging of the seed or to environmental conditions during the reproductive phase.…”

Section: Field Studiesmentioning

confidence: 99%

Effect of seeding date on canola seed quality and seed vigour

Gusta¹,

Johnson²,

Nesbitt³

et al. 2004

. 2004. Effect of seeding date on canola seed quality and seed vigour. Can. J. Plant Sci. 84: 463-471. Seedling vigour is a key critical component to produce well-established canola (Brassica napus) seedlings under less than ideal conditions in western Canada. Our objective was to determine if seed lots from late October (fall) or early spring (April) seeding dates improve seed vigour relative to mid-May (May) seeding dates. We compared seed size, seed maturity, germination percentage, and seedling emergence under controlled-environment conditions from six seed lots obtained from fall-sown (1997, 1998), April-sown (1998April-sown ( , 1999 and May-sown canola (1998May-sown canola ( , 1999 cv. Quest. On average, 80% of fall-derived seed for both years was larger than 1.7 mm compared to only 32% for May-derived canola seed. April-derived seed was intermediate. Fall and April derived seed were considered 40% mature compared to 16% for May-derived seed. In germination tests at 8°C, May derived seed germinated and emerged slower with a lower total germination percentage compared to falland April-derived seed lots. Priming reduced differences in emergence between the seed lots. Field studies at Scott, SK, sown in the fall of 1999 and 2000, and in early May of 2000 demonstrated that seed derived from fall-and April-sown canola produced higher plant densities, higher biomass at bolting, and higher seed yield than seed derived from May-sown canola. Yield was 10 to 45% less from seed derived from May-sown canola than seed derived from fall-and April-sown canola. This study established the impact of seeding date on seed quality and vigour, which in turn affected emergence, seedling vigour and yield. Also, seed vigour slowly declined within 1 yr, primarily with seed derived from the May-sown canola. Le canola issu des semences de mai donne un rendement de 10 à 45 % inférieur à celui du canola venant des graines d'automne ou d'avril. L'étude illustre bien l'incidence de la date des semis sur la qualité et la vigueur des graines, ce qui a un effet sur la levée, la vigueur des plants et le rendement. Par ailleurs, la vigueur des graines du canola semé en mai s'affaiblit à mesure que l'année progresse.Mots clés : canola, Brassica napus, vigueur (graines), semis (automne), levée, rendement (qualité) Seed germination and seedling emergence result from a sequence of biological events initiated by water imbibition followed by enzymatic metabolism of storage nutrients. All of those events are regulated by the environment and the quality of the seed. Low soil temperature and lack of available soil moisture in the spring delay and reduce seedling emergence, particularly in small seeded crops such as canola (Brassica spp.). The mean spring soil temperature in the canola production area of western Canada ranges from 5 to 13°C at a 5-cm depth. The optimal temperature for canola seed germination and emergence is 15 to 20°C (Kondra et al. 1983). Both suboptimal soil temperature and lack of soil moisture delay and reduce germination perce...

“…Poor plant establishment after fall seeding is usually related to inadequate or excessive moisture, high fall temperatures and soil crusting (Kirkland and Johnson 2000;Angadi et al 2003). Incomplete acclimation results in cool temperature seedling injury and subsequent mortality after repeated spring frosts can also contribute to low plant density from fall-seeded canola (Gusta and O'Connor 1987;Kirkland and Johnson 2000;Sparrow et al 1990). Optimum canola populations have been reported to be 80 to 180 plants m -2 (Thomas 2002).…”

mentioning

confidence: 99%

Polymer seed coating of early- and late-fall-seeded herbicide-tolerant canola (Brassica napus L.) cultivars

Clayton¹,

Harker²,

O’Donovan³

et al. 2004

, T. 2004. Polymer coating of early-and late-fall-seeded herbicide-tolerant canola (Brassica napus L.) cultivars. Can. J. Plant Sci. 84: 971-979. Polymer seed coatings offer an opportunity to fall seed Brassica napus earlier in October, thus avoiding difficult seeding conditions (wet/frozen soils) common in late October or early November. A multi-year field experiment was conducted at four locations in Alberta, Canada, to investigate the effect of early (mid-October) and late fall (late October-early November) canola seeding with and without a germination-inhibiting polymer seed coat. Yield and yield components were determined in glufosinate (hybrid and open-pollinated), glyphosate (open-pollinated), and imidazolinone (open-pollinated) herbicide-tolerant canola cultivars. Early-seeded canola without the polymer coat had a reduced plant density of 58% compared to late-fall-seeded canola. Application of the polymer coat on early-seeded canola increased plant density by 80% compared to uncoated seed. Seed yield and dockage were not affected by seeding date when a polymer seed coating was used. Without the polymer seed coat, canola yield was reduced 42% and dockage increased 6% when seeding occurred in early vs. late fall. Increased pod production from early-fall-seeded uncoated canola compared to other seeding dates could only partially compensate for canola yield. Cultivar interactions generally were not agronomically important. The use of polymer seed coatings with all these herbicide-tolerant cultivars will allow producers to seed earlier in fall, rather than waiting for cooler soil conditions in late fall.. et Ferguson, T. 2004. Enrobage des graines de cultivars de canola (Brassica napus L.) tolérant les herbicides semées au début et à la fin de l'automne avec un polymère. Can. J. Plant Sci. 84: 971-979. L'enrobage des graines de Brassica napus avec un polymère per-met de les semer plus tôt en octobre et ainsi d'éviter les conditions souvent difficiles (sol humide ou gelé) survenant à la fin d'oc-tobre et au début de novembre. Plusieurs années durant, les auteurs ont effectué des essais sur le terrain à quatre endroits en Alberta (Canada) en vue d'établir l'incidence des semis au début (mi-octobre) et à la fin de l'automne (de la fin d'octobre au début de novembre) avec et sans enrobage des semences avec un polymère inhibant la germination. Le rendement et les composantes du rendement ont été mesurés avec des cultivars tolérant le glufosinate (hybrides et pollinisation libre), le glyphosate (pollinisation libre) et l'imidazolinone (pollinisation libre). Sans polymère, les cultivars semés au début de l'automne présentaient une densité de peuplement de 58 % plus faible que celui des cultivars semés à une date ultérieure. Le polymère accroît la densité de peuple-ment des cultivars semés au début de l'automne de 80 % comparativement à ceux dont la semence n'avait pas été traitée. Le ren-dement grainier et la proportion de criblures ne sont pas affectés par la date des semis quand les semences sont enrobées de polym...