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

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. 2004. Seeding date and polymer seed coating effects on plant establishment and yield of fall-seeded canola in the Northern Great Plains. Can. J. Plant Sci. 84: 955-963. The time interval for planting fall-seeded Brassica napus L. canola in the Northern Great Plains is narrow, since seeding must occur as close to soil freeze-up as possible to minimize the risk of winter kill. The Prairie ecoregion tends to have more stable fall and winter temperatures than the Rocky Mountain foothill region, where fall and winter chinooks may initiate germination and increase the risk of winter mortality. Our objectives were to determine an optimum seeding date interval for fall-seeded canola and whether a water-impervious polymer seed coating could advance the seeding date and reduce the risk of stand loss and corresponding yield reduction in two distinct agroecoregions. A range of fall seeding dates and a water-impervious polymer seed coating vs. a control treatment (water-soluble film) were assessed at 14 sites (five locations) from 1998 to 2001 in Alberta and Saskatchewan (Prairie sites) and at six sites (four locations 1999-2001) in Montana, USA (Foothill sites). Highest seedling densities and canola yield responses for the control treatment were attained in the first 2 wk of November in the Prairie sites, while responses to seed date were much more variable in the Foothill region. In the Prairie sites, the water-impervious polymer seed coating improved seedling density and seed yield as seeding date was progressively moved forward from the first week of November to the first week of October. The benefit of the water-impervious polymer seed coating became notable when soil temperatures were above 5°C. The water-impervious polymer coating provided only marginal improvement in plant stand and canola yield in the Foothill region. In the Foothill region and at Lethbridge, fall-seeded canola densities were on average 60% lower than spring-seeded canola densities and fall seeding increased canola yield in only one site-year when compared with spring-seeded canola. In the Prairie region, a water-impervious polymer coating can broaden the time interval for fall seeding; however, it does not ensure that recommended densities of spring seedlings will be attained. The optimum seeding date for fall seeding in the Foothill region could not be adequately defined for either the control or the water-impervious polymer coated seed due to the variable nature of the late fall and winter weather. Le laps de temps dont on dispose pour semer le canola (Brassica napus L.) à l'automne dans le nord des grandes plaines est relativement court, car l'opération doit survenir aussi plus près que possible de la date où le sol gèle si l'on veut réduire les risques de destruction par l'hiver. L'écorégion des Prairies a tendance à connaître des températures automnales et hivernales plus stables que celle des contreforts des Rocheuses où le chinook amorce parfois la germination, donc accroît les risques de mortalité hivernale. Les auteurs voulaient établir...

Section: Prairie Ecoregionsupporting

confidence: 73%

Seeding date and polymer seed coating effects on plant establishment and yield of fall-seeded canola in the Northern Great Plains

Johnson¹,

Miller²,

Blackshaw³

et al. 2004

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“…Spring seeded canola plant density generally surpassed the specified critical level (Clayton et al 2004a). Among fall seeded canola, Beaverlodge showed a higher chance of density exceeding the critical level than either Lacombe or Lethbridge (Clayton et al 2004b). Early fall seeding treatments with PSC consistently had a lower probability of thin stand compared with without PSC across all locations.…”

Section: Re-seeding Canolamentioning

confidence: 87%

“…They found higher yield for canola planted in early spring as opposed to fall dormant or traditional normal spring seeding dates. Premature germination has been reported as a major yield-reducing factor for dormant fall seeded canola in the northern prairies (Kirkland and Johnson 2000;Clayton et al 2004b). Polymer seed coating could be a major innovation for fall seeding canola.…”

mentioning

confidence: 99%

“…Kirkland and Johnson (2000) indicated that PSC might benefit farmers by reducing the risk associated with erratic late fall or early spring temperature fluctuations, and would permit earlier seeding in the fall. Clayton et al (2004b) hypothesized that PSC in fall dormant seeded canola may prevent premature germination and thus result in higher canola yield. The potential of this technology to increase profitability and/or reduce business risk in canola has not been evaluated.…”

mentioning

confidence: 99%

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Economic evaluation of seeding decisions in hybrid and open-pollinated herbicide-resistant canola (Brassica napus)

Upadhyay¹,

Smith²,

Clayton³

et al. 2005

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. Economic evaluation of seeding decisions in hybrid and open-pollinated herbicide-resistant canola (Brassica napus). Can. J. Plant Sci. 85: 761-769. Herbicide-resistant canola (Brassica napus) is widely cultivated in western Canada. Data from a multi-year field experiment conducted at three locations in Alberta were used to investigate the effect of canola cultivar, time of seeding, polymer seed coating (PSC) on profitability and the net return risk. Cultivars included hybrid and open pollinated. Time of seeding was early and late fall, and early and normal spring. The hybrid canola generally had higher mean net return than the open-pollinated cultivar. The probability of thin canola stand was higher for fall dormant seeding compared with spring seeding. The use of PSC for early fall dormant seeding reduced the likelihood of thin canola stand, which translated into risk-efficient decision. However, PSC use for late fall seeding had mixed results. Early and normal spring seeding was generally risk-efficient at all locations. In exceptional cases, net returns from late fall dormant seeding (with or without PSC) were similar to that of spring seeding. Re-seeding of fall seeded canola in the spring could be beneficial, if the plant density was below 20 plant m -2 . Seeding decisions were robust across a wide range of canola prices, based on the probability of negative net returns. Les auteurs ont recouru aux données d'une expérience de plusieurs années effectuée sur le terrain à trois endroits de l'Alberta pour vérifier l'incidence du cultivar, du moment des semis et de l'enrobage des semences avec un polymère (ESP) sur la rentabilité et le risque relatif au rendement net de la culture. Les auteurs ont testé des cultivars hybrides et à pollinisation libre. Les graines ont été semées au début de l'automne, à la fin de l'automne, au début du printemps et à la date usuelle au printemps. Les cultivars hybrides donnent généralement un rendement net moyen plus élevé que les variétés à pollinisation libre. La probabilité d'un peuplement clairsemé est plus importante avec les graines dormantes semées en automne qu'avec celles semées au printemps. L'enrobage des graines dormantes semées au début de l'automne atténue les risques d'un peuplement clairsemé, ce qui facilite la prise de bonnes décisions par rapport aux risques. Néanmoins, employé avec les graines semées à la fin de l'automne, ce traitement donne des résultats mitigés. Les semis au début du printemps et au moment usuel donnent généralement de bons résultats à tous les endroits, compte tenu des risques. Sauf dans des cas exceptionnels, le rendement net des graines dormantes semées à la fin de l'automne (avec ou sans ESP) est analogue à celui obtenu avec les semis printaniers. Un réensemencement printanier du canola semé à l'automne pourrait donner des résultats intéressants quand la densité du peuplement est inférieure à 20 plants au mètre carré. Les décisions relatives aux semis restent robustes pour une grande fourchette de prix, compte tenu de l'éventualité d'u...

“…Dormant fall seeding of canola has become more feasible with the introduction of herbicide tolerant canola varieties, and the development of a polymer seed coat (Extender ® ) that prevents seed germination in the fall. In Alberta, canola plant density and yield were improved considerably when the polymer was used on canola seed planted in early October prior to soil freeze-up (Clayton et al 2004b). Reported benefits of fall-compared with spring-seeded canola in western Canada are variable.…”

mentioning

confidence: 99%

Effect of fall and spring seeding on canola productivity in the Peace River region of northern Alberta

O’Donovan¹,

Otani²,

Clayton³

et al. 2005

. 2005. Effect of fall and spring seeding on canola productivity in the Peace River region of northern Alberta. Can. J. Plant Sci. 85: 641-644. The feasibility of dormant seeding canola in the fall in the Peace River region of northern Alberta was assessed. Results indicated that there is a significant risk of crop failure with fall seeding, mainly due to poor spring seedling emergence. Where a fall-seeded canola crop established, flowering and seed maturity occurred earlier even though plant densities were lower with fall compared with spring seeding, and seeding date had little or no effect on canola seed yield or quality. Tillage (minimum or zero) or nitrogen rate, source or placement had no consistent effects on canola productivity. Canola growers in the Peace River region are unlikely to achieve higher yield and quality by seeding canola in the fall.Key words: Dormant seeding, fertilizer rate, source and placement, minimum and zero tillage, polymer coated canola seed O'Donovan, J. T., Otani, J., Clayton, G. W. et Soon, Y. K. 2005. Incidence des semis automnaux et printaniers sur la productivité du canola dans la région de la Rivière-de-la-Paix du nord de l'Alberta. Can. J. Plant Sci. 85: 641-644. Les auteurs ont essayé de déterminer si on peut semer des graines dormantes de canola à l'automne dans la région de la Rivière-de-la-Paix, dans le nord de l'Alberta. Les résultats indiquent que la culture court de grands risques d'échouer, principalement à cause d'une piètre levée au printemps. Quand la culture semée à l'automne parvient à s'établir, la floraison et la maturation des graines surviennent plus tôt même si les peuplements sont moins denses que ceux obtenus avec des semis printaniers. Dans ce cas, la date des semis a peu d'effet, sinon aucun, sur le rendement grainier et la qualité des graines de canola. Les labours (travail minimal ou nontravail du sol), le taux d'application des engrais azotés, la provenance de l'engrais et la méthode de placement n'ont pas d'incidence cohérente sur la productivité du canola. Les producteurs de canola de la région de la Rivière-de-la-paix. ne devraient pas voir le rendement ni la qualité de leurs cultures s'améliorer avec des semis automnaux.