WO2011028115A1

WO2011028115A1 - Controlled seed wetting

Info

Publication number: WO2011028115A1
Application number: PCT/NL2010/050554
Authority: WO
Inventors: Robert Jean Legro; Fransiscus Abraham Antonius Tetteroo; Paulus Ludovicus Servatius Klemann
Original assignee: Incotec International B.V.
Priority date: 2009-09-04
Filing date: 2010-09-03
Publication date: 2011-03-10
Also published as: CN102625650B; JP2013503629A; KR20120124385A; CN102625650A; BR112012004903A2; JP5757949B2

Abstract

The invention is directed to a method for preparing a coated seed and to a coated seed obtainable by said method. The method of the invention comprises providing a non-germinated seed and a) coating said seed with a coating composition comprising one or more binders and one or more active ingredients; and b) wetting said seed in a liquid, said liquid comprising an amount of water sufficient to induce germination, wherein said amount of water is such that essentially all the water is absorbed by the seed prior to germination of said seed.

Description

Title: Controlled seed wetting

The invention is directed to a method for preparing a coated seed and to a coated seed obtainable by said method.

For various reasons it can be desirable to provide seeds with a coating. Such a coating may for instance, protect the seeds from damage or may reduce the dust or may improve the plant ability by increasing the flow characteristics. Advantageously, the coating can comprise active ingredients that are able to assist in protecting the seeds and/or seedlings emerging from the seed, for instance against diseases from e.g. fungi or bacteria, or in protecting the seeds against pests from insects or nematodes. In addition, it is possible to apply a coating that contains active ingredients that are

advantageous for the seeds and/or the emerging seedlings, such as nutrients or growth regulators. Further, a seed coating may be applied to change the appearance of the seed, such as by giving the seed a coloured and/or a reflective appearance. Seed coating has become common practice.

On the other hand, it can be favourable to soak seeds in water or an aqueous solution prior to sowing so that the seeds can absorb water. Such seed wetting (in particular for specific types of seed, such as rice seed) generally results in faster and more uniform sprouting, a more uniform plant stand, and a quicker plant establishment. Conventionally, seed wetting is performed by soaking the seeds in a large excess of water of which the excess of water is drained after the soaking treatment.

One of the problems faced when combining coating and wetting of seeds is that the coating, including any active ingredients comprised therein, may be washed off during soaking in the excess of water or the draining. This considerably decreases the overall activity of active ingredient on the seed.

Depending on the soaking conditions, the active ingredient may even be totally lost.

It is not possible to solve this problem by reversing the steps of coating and soaking as described in WO-A-2005/077169, because then each farmer would need to have a coating apparatus. In addition, after soaking the seeds become much more vulnerable for mechanical stress during the coating step. Furthermore, the amount of coating liquid (slurry) that can be applied to soaked wet seeds is limited.

Other attempts to solve the above-sketched problem have been made. For instance, it is known to first soak the seeds in water and, after germination, spray a solution that contains active ingredient over the seeds. However, this typically results in an undesirable non-uniform distribution of the active ingredient over the seeds.

EP-A-0 904 681 describes a method for treating seeds in which the water content is controlled by using a semi-permeable membrane. The water content is kept below the level at or above which germination is possible.

There is no contact between seed and the osmotic material that wets the seed and the seeds need to be dried after the treatment. This document does not explicitly teach that essentially all the water required for inducing

germination should be absorbed prior to germination of the seed. Furthermore, this document does not teach or suggest coating the seed before wetting the seed.

Object of the invention is to provide a solution to the above- sketched problem and to provide a method which advantageously allows the

combination of coating seeds with a coating that contains one or more active ingredients and wetting of seeds.

The inventors came to the insight that the active ingredient in the seed coating is not (or only hardly) lost, when the amount of water used for soaking the seeds is adjusted to the amount of water that the seeds can absorb.

Accordingly, in a first aspect the invention is directed to a method for preparing a coated seed, comprising providing a non-germinated seed and a) coating said seed with a coating composition comprising one or more

binders and one or more active ingredients; and b) wetting said seed in an amount of water sufficient to induce germination, wherein said amount of water is such that essentially all the water is absorbed by the seed prior to germination of said seed.

By using an amount of water such that essentially all the water is absorbed by the seed, the inventors surprisingly found that no (or hardly any) active ingredient is washed off from the seed. Hence, the method of the invention allows combining the advantages of seed coating, with the advantages of seed wetting, which combination was heretofore not achieved.

The term "seed coating" as used in this application is meant to refer to any process whereby the seed is treated with one or more adhering coating layers. This term is meant to include film coating (application of a continuous or non-continuous layer of polymer film) but also pelleting (deposition of one or more layers of inert material to substantially increase seed weight and to improve seed plant ability), and combinations thereof.

The term "seed wetting" as used in this application is meant to refer to any process whereby the seed is led to absorb a liquid. Accordingly, the seed is in direct contact with the liquid. The liquid is preferably water, or an aqueous solution which may optionally comprise nutrients, gene eliciting agents such as harpin protein (commercially available from Plant health Care as Harpin), chitosan penta saccharide (commercially available from AgriHouse as YEA!™), or lipochitooligosaccharide (commercially available from EMD as Optimize^® LCO), protecting agents, growth regulators, etc.

The term "active ingredient" as used in this application is meant to refer to any component that is in one way or another advantageous for a plant or a plant seed. A plant or plant seed in this context includes a pelleted seed, a true seed, a plant seedling, a rootstock, plant cuttings or plant parts (such as a potato tuber or flower bulb).

The term "germination" as used in this application is meant to refer to the process wherein the embryonic axis emerges from its surrounding structures. Usually, this corresponds to a radicle emerging from the testa or pericarp.

The expression "to induce germination" as used in this application is meant to include the initiation of physiological processes (such as respiration, protein synthesis, DNA replication etc.) within the seed which are needed for germination (radicle emergence) due to water uptake of non-germinated seed.

In accordance with the method of the invention a non- germinated seed is provided. This may be any kind of seed. The seed may be primed or unprimed. Further, the seed can be of the order of Monocotyledoneae or from the order of Dicotyledoneae. A preferred example from the order of

Monocotyledoneae is rice seed. More preferably the seed is a rice seed selected from the group consisting of Oryza sativa japonica, Oryza glaherrima javanica, Oryza sativa indica, Zizania palustris, and hybrids thereof. A preferred example from the order of Dicotyledoneae is oil seed rape (Brassica napus).

Optionally, the seed may be deprived of husk (so-called husked seed or de-hulled seed). This may be done by using twin rolls. More specifically, intact seeds can be passed between twin rolls with a predetermined gap between the rolls, one of which rolls has a rotation speed and a rotation direction different from those of the other roll. This causes suitable friction between the twin rolls and the intact seeds to remove the husk from the seeds. If this operation does not completely remove the husk from the seeds, the operation may be repeated. The rotation speed and gap of the twin rolls can be suitably determined by the person skilled in the art. Such husking of seeds may be particularly suitably in the case of rice seeds, as described for instance in WO-A-01/78507.

The seed is coated with a coating composition comprising one or more binders and one or more active ingredients. Conventional means of coating may be employed for coating the seeds. Various coating machines are available to the person skilled in the art. Some well-known techniques include the use of drum coaters, fluidised bed techniques, rotary coaters (with and without integrated drying) and spouted beds. It is further possible to film-coat the seeds with film-forming compositions. A film coating can be applied directly on the seed, but also as an overcoat on a seed which already has a coating.

The coating composition comprises one or more binders. Many suitable binders are known. The binder can for example be selected from the group consisting of polyvinyl acetates, polyvinyl acetate copolymers, polyvinyl alcohols, polyvinyl alcohol copolymers, polyurethane, celluloses (including ethylcelluloses and methylcelluloses, hydroxymethylcelluloses,

hydroxypropylcellulose, ethylcellulose, carboxymethylcellulose and

hydroxymethylpropylcelluloses), polyvinylpyrolidones, dextrins,

malto-dextrins, polysaccharides, fats, oils, proteins, gum arabics, shellacs, vinyhdene chloride, vinyhdene chloride copolymers, calcium lignosulphonates, acrylic copolymers, starches, polyvinylacrylates, zeins, casein, gelatin, chitosan, pullulan, polyethylene oxide, ethylene vinylacetate, acrylimide polymers and copolymers, polyhydroxyethyl acrylate, methylacrylimide monomers, poly(N-vinylacetamide), sodium alginate, polychloroprene and syrups. Also waxes such as carnauba wax, paraffin wax, polyethylene wax, bees wax, and polypropylene wax can be used as a binder. These binders may be used alone or in combination of two or more. Preferred binders include polyvinyl acetates, polyvinyl alcohols, hydroxypropyl methyl cellulose, polysaccharides (such as starch), proteins, polyethylene glycol, and polyvinyl pyrrolidones.

The amount of binder in the coating composition is normally in the range of 0.1-100 g per kg of the seed, preferably 0.5-50 g per kg of the seed, more preferably 1-20 g per kg of the seed. Based on the total weight of the coating composition, the amount of the binder in the coating composition can be 1 wt.% or more, preferably 10 wt.% or more, and 80 wt.% or less, preferably 60 wt.% or less. The coating composition further comprises one or more active ingredients. Suitable examples of active-ingredients are fungicidal agents, bactericidal agents, insecticidal agents, nematicidal agents, molluscidal agents and other biocides. Further active ingredients include disinfectants, micro-organisms, rodent killers, weed killers (herbicides), attracting agents, repellent agents, plant growth regulators (such as gibberellic acid, auxin or cytokinin), nutrients (such as potassium nitrate, magnesium sulphate, iron chelate), plant hormones, minerals, plant extracts, acaricides or miticides, molluscicides, germination stimulants, pheromones, biological preparations, chitosan, chitine-based preparations, etc.

The amount of active ingredient applied, of course, strongly depends on the type of active ingredient and the type of seed used. Usually, however, the amount of one or more active ingredients is in the range of 0.001-200 g per kg of the seed. The skilled person is able to determine suitable amounts of active ingredient depending on the active ingredient and the type of seed used.

Typical fungicidal agents include Captan (N-trichloromethyl)thio- 4-cyclohexane- 1,2-dicarboximide), Thiram (tetramethylthioperoxydicarbonic diamide; commercially available as Proseed™), Metalaxyl (methyl

N- (2 , 6- dimethylphenyl) - N- (methoxyacetyl) - DL-alaninate) , Fludioxonil

(4-(2,2-difluoro- l,3-benzodioxol-4-yl)- l-H-pyrrol-3-carbonitril; commercially available in a blend with mefonoxam as Maxim™ XL), difenoconazole

(commercially available as Dividend™ 3FS), carbendazim iprodione

(commercially available as Rovral™), ipconazole, mefonoxam (commercially available as Apron™ XL), tebuconazole, carboxin, thiabendazole, azoxystrobin, prochloraz, and Oxadixyl (N-(2,6-dimethylphenyl)-2-methoxy-

N-(2-oxo-3-oxazolidinyl) acetamide). A fungicide can be included in the seed coating composition in an amount of 0.0001- 10 wt.%, based on the total weight of the coated seeds.

Typical bactericidal agents include streptomycin, penicillins, tetracyclines, ampicillin, and oxolinic acid. Typical insecticidal agents include pyrethroids, organophosphates, caramoyloximes, pyrazoles, amidines, halogenated hydrocarbons,

neonicotinoids, and carbamates and derivatives thereof. Particularly suitable classes of insecticides include organophosphates, phenylpyrazoles and pyrethoids. Preferred insecticides are those known as terbufos, chlorpyrifos, fipronil, chlorethoxyfos, tefluthrin, carbofuran, imidacloprid, and tebupirimfos. Commerially available insecticides include imidacloprid (commercially available as Gaucho™), and clothianidin (commercially available from Bayer as Poncho™), thiametoxam (commercially available from Syngenta as Cruiser™) and fipronil (commercially available from BASF as Regent™).

Commercially available nematicidal agents include abamectin (commercially available from Syngenta as Avicta™) thiodicarb (commercially available from Bayer as Aeris™).

Typical molluscidal agents include metaldehyde (commercially available from Lonza as Meta^®) or niclosamid (commercially available from Bayer as Bayluscide^®).

The coating composition can comprise further components such as a wetting and dispersing additive (sometimes also referred to as pigment dispersant), a filler, a solvent, a thickener, a colouring agent, an anti-foaming agent, a biocide, a surfactant and an effect pigment.

A wetting and dispersing agent can aid in mixing inorganic particles in the seed coating composition and can further have a positive effect on the flow ability of coated seeds. Suitable wetting and dispersing additives include ionic and non-ionic products and include solutions of organo-modified polyacrylates, polyacrylates, sodium polyacrylate, polyurethane, phosphoric acid ester, star polymers, and/or modified polyethers. The wetting and dispersing additive can for instance be present in the seed coating composition of the invention in an amount of 0-40 wt.%, based on the total weight of the inorganic particles. Suitable thickeners include agar, carboxy methylcellulose, carrageen, chitin, fucoidan, ghatti, gum arabic, karaya, laminaran, locust bean gum, pectin, alginate, guar gum, xanthane gum and tragacanth, bentonite clays, HEUR (hydrophobically modified, ethoxylated urethane) thickeners, HASE (hydrophobically modified, alkali- swellable emulsion) thickeners and polyacrylates. Gums are generally preferred because of their low cost, availability and superior ability to enhance the physical characteristics of the resultant film.

Suitable colouring agents can be dyes or pigmented colorants.

Suitable dyes include: anthraquinone, triphenylmethane, phthalocyanine and derivatives thereof, and diazonium salts. Colorants can contain pigments such as pigment red 112 (CAS No. 6535-46-2), pigment red 2 (CAS No. 6041-94-7), pigment red 48:2 (CAS No. 7023-61-2), pigment blue 15:3 (CAS No. 147-14-8), pigment green 36 (CAS No. 14302-13-7), pigment green 7 (CAS No. 1328-53-6), pigment yellow 74 (CAS No. 6358-31-2), pigment orange 5 (CAS No.

3468-63-1), pigment violet 23 (CAS No. 6358-30-1), pigment black 7 (CAS No. 97793-37-8), and pigment white 6 (CAS No. 98084-96-9). The colouring agent may be present in the seed coating composition in an amount of 0-50 wt.%, based on the total weight of the coating composition.

Suitable anti foaming agents include polyethylene glycol, glycerine, mineral oil defoamers, silicone defoamers, and non silicone defoamers (such as polyethers, polyacrylates), dimethylpolysiloxanes (silicone oils), arylalkyd modified polysiloxanes, polyether siloxane copolymer containing fumed silica. The anti foaming agent may be present in the seed coating composition of the invention in an amount of 0.1-0.3 wt.%, based on the total weight of the coating composition.

Suitable effect pigments include pearlescent pigment in different particle sizes. Effect pigments having a particle size of 15 μηι or less, or a particle size of 60 μηι or less are commonly used. The particle size of the effect pigments is normally not more than 200 μηι, preferably not more than 100 μηι. Usually, the particle size of the effect pigment is 1 μηι or more. Another effect pigment can be aluminium. All effect pigments are commonly used to create a nice cosmetic look on the seeds.

A biocide can be included in the seed coating composition of the invention in order to prolong the shelf life of the seed coating composition before being applied to a seed, such as when being stored. Suitable biocides include MIT (2-methyl-4-isothiazolin-3-one, CAS No. 2682-20-4) and BIT (l,2-benzisothiazolin-3-one; CAS No. 2632-33-5).

In an embodiment the coating composition further comprises flakes of a translucent polymeric film on an inert carrier (a carrier which has no detectable, harmful consequences for the environment, in particular for the seed or the outgrowing plant in the quantities present) for providing the seeds with a light-reflecting appearance, such as described in WO-A-03/003812. Preferably, the translucent polymeric film comprises light-reflecting particles.

The method of the invention further requires a step wherein the seed is wetted in a liquid. The liquid comprises an amount of water sufficient to induce germination, wherein said amount of water is such that essentially all the water is absorbed by the seed prior to germination of said seed. The liquid can consist of water, but may optionally comprise further components. The liquid may for example also be an aqueous solution containing e.g.

nutrients.

Wetting can be performed as a single step, but it is also possible to wet the seed in two or more steps separated in time, as long as the overall amount of water used is sufficient to induce germination and that essentially all of the water supplied is absorbed by the seed prior to germination.

In an embodiment, the wetting is performed in a single step for at least 5 minutes. The exact duration of the wetting step depends on the type of seed. The wetting step can for instance take at least 10 minutes or at least 1 hour. Furthermore, depending on the type of seed, the wetting step preferably does not last more than 72 hours, more preferably not more than 48 hours, or not more than 30 hours.

The seed is normally wetted at a temperature of 0-40 °C, such as 5-40 °C, depending on the type of seed. For example, it is preferred to wet rice seed at a temperature of 25-35 °C, such as 25-30 °C, whereas OSR (oil seed rape) seed is preferably wetted at a temperature of 15-25 °C.

Usually, the amount of water is 20-50 wt.% based on total wet seed weight (i.e. the weight of the seed including absorbed water after the wetting step), preferably 25-40 wt.% based on total wet seed weight, more preferably 30-35 wt.% based on total wet seed weight. At the end of the wetting step, the water activity of the seed is preferably 0.95 or more, more preferably 0.98 or more, and most preferably in the range of 0.99-1.0.

During the wetting phase the seeds are preferably turned, rolled or manually moved. This results in more uniform moisture uptake from seed to seed and better oxygen availability.

Furthermore, it is possible to add oxygen releasing compounds and/or oxygen in the form of gas during the wetting treatment (such as in solution) in order to meet at least some of the oxygen needs of the seeds of which the germination is induced.

In accordance with the invention, the amount of water is such that essentially all the water is absorbed by the seed prior to germination of the seed. With this expression it is meant that 95-100 wt.% of the amount of water used for wetting is absorbed by the seed prior to germination, preferably 98-100 wt.%, more preferably 100 wt.%.

It is preferred in accordance with the invention to coat the seeds prior to wetting. Advantageously, this allows active ingredients present in the seed coating to be absorbed into the seed together with the water that is provided during the wetting step. Due to the limited amount of water the one or more active ingredients will not be washed off and wasted. An optional incubation step may be performed after the wetting step, during which the seed is maintained at a high water content and specific temperature. Preferably, the water activity of the seed is maintained during incubation at a value of 0.95 or more, more preferably 0.98 or more, and most preferably in the range of 0.99-1.0. Such an incubation step may further get the germination process going. Incubation of the seed can for instance be done at a temperature of 5-40 °C, such as at a temperature of 25-35 °C, 25-30 °C, 15-25 °C, or 15-20 °C.

In an embodiment, the seeds are subjected to a heat treatment process. This heat treatment can be conducted prior to or after the method of the invention. Such heat treatment may involve supplying to the seeds non-water-borne heat while regulating the treatment time and temperature depending on the condition and moisture content of the seeds. More

specifically, the seeds, by supply of hot air, can be heated for a short period of time to a predetermined temperature, while not changing the moisture content of the seeds. Thereafter, the seeds can be kept warm during a predetermined time with constant temperature and moisture content. Such heat treatment is e.g. disclosed in WO-A-97/38734. Application of such heat treatment allows efficient disinfection of the seeds by means of a carefully controlled heating.

Optionally, after the method of the invention has been completed, additional water may be applied to the seed, e.g. in order to promote growth after germination.

In a further aspect, the invention is directed to a seed obtainable by the method of the invention. The seed advantageously combines a high moisture content (typically 25-50 wt.%), with an active ingredient- containing coating.

The invention will now be further demonstrated by means of the following Examples, which are not intended to limit the present invention in any way. Example 1

For the first example Oryza japonica seeds of cultivar Koshihikari were used. The seed was coated in a 30 cm rotary coater with spinning disc. The batch size was 575 g. A mixture was made of film coat formulation Disco AG red L200 (commercially available from Incotec), water and Gaucho^® 70 WP (commercially available from Bayer) in a weight ratio of 10:15:12.6. The mixture was applied in the coating machine at such a dose that the Gaucho^® dose was 12.6 g/kg seed. The seed batch was subsequently dried in a seed dryer at 35 °C for 2 hrs. The resulting moisture content was measured with an oven protocol (4 hours at 130 °C) and was 11.5 wt.% based on total wet seed weight.

Based on the determined water content (11.5%) and the target resulting water content after treatment (27.5 wt.% and 30 wt.%) the water quantity to be added in the wetting step was calculated according to the following formula:

w_wa = 7——— ,xw_s x{ioo% - Μ )- ^χ Μ

w^a (100 % - C₂ )

wherein W_wa is the weight of water to be added in gram, MC_X is the initial moisture content of the seed in wt. %, MC₂ is the target moisture content of the seed in wt. %, and W_s is the initial seed weight in gram (i.e. the weight of the seed before the wetting step).

With a seed moisture content after film coating and drying of 11.5 wt.% and a target moisture content of 27.5 wt.%, 126.9 g water had to be added to 575 g seed.

The coated seed quantity of 575 g was poured into a container with airtight lid. The calculated quantity of water was added and the lid was placed on the container. The container was shaken in order to distribute the water in the seed. The container was than placed at 30 °C for 24-48 hours. During this period the seed container was manually turned upside down and back two times per 24 hours to redistribute the water uniformly. After the wetting period all the added water had been absorbed. The treated seeds (800 per treatment) were planted in germination boxes containing Japanese rice soil 510 ml saturated with water, after which the seeds were covered on top with 255 ml Japanese rice soil. After sowing both soil layers were pressed.

Germination conditions were 3 days dark 28-30 °C followed by 4 weeks 25 °C greenhouse.

Watering in greenhouse was done with a tidal system, flood time 30 min. once every 2 days; later, when plants really start growing the regime was increase to 1 time each day.

The results of these examples are shown in Figure 1. This Figure shows two comparative samples wherein coated seed was not wetted (2 boxes in the front), four samples wherein coated seed was wetted for 24 h to a moisture content of 27.5 wt.% based on wetted seed weight, four samples wherein coated seed was wetted for 24 h to a moisture content of 30 wt.% based on wetted seed weight, four samples wherein coated seed was wetted for 48 h to a moisture content of 27.5 wt.% based on wetted seed weight, and four samples wherein coated seed was wetted for 48 h to a moisture content of 30 wt.% based on wetted seed weight. This Figure clearly demonstrates that the seeds which were treated with the method of the invention grow quicker and more uniform than the seeds of the comparative example.

Example 2 For the second example Oryza indica seeds cultivar OMCS 2000 were used. The seed was coated in a 30 cm rotary coater with spinning disc. The batch size was 575 g. A mixture was made of film coat formulation Disco AG red L200 (commercially available from Incotec), water and Cruiser^® 70 WP (commercially available from Syngenta) in a weight ratio of 10:20:16. The mixture was applied in the coating machine at such a dose that the Cruiser^® dose was 16 g/kg seed. The seed batch was subsequently dried in a seed dryer at 35 °C for 2 hrs. The resulting moisture content was measured with an oven protocol (4 hours 130 °C) and was 9.5 wt.% based on total wet seed weight.

Based on the determined water content and the target resulting water content after treatment, the water quantity to be added was calculated. For example: with a seed moisture content after film coating and drying of 9.5 wt.% and a target moisture content of 27.5 wt.%, 142.8 g water had to be added to 575 g seed.

The seed quantity of 575 g was poured in a container with airtight lid. The calculated quantity of water was added and the lid was placed on the container. The container was shaken in order to distribute the water in the seed. The container was than placed at 30 °C for 24-48 hours. During this period the seed container was continuously turned upside down and back to redistribute the water. After this period the water had been absorbed. The water activity was determined at the end of the wetting period and was 0.997.

For comparison, the same amount of seeds was also treated with the traditional Thai soaking method with excess of water (2 litres). After the treatment the remaining active ingredients were measured with standard HPLC methodology (UV detector 220 nm, C18 reverse phase column and methanol). The results of this comparison are shown in Figure 2. This figure clearly shows that in accordance with the invention, the active ingredient remains on the seeds (dotted line), whereas with traditional soaking (using an excess of water) all the active ingredients were washed off (solid line).

Figure 3 shows a cumulative germination curve of the seeds of Example 2. This figure demonstrates that seed treated with the method of the invention (curve B, film-coated seed wetted for 24 hours to a water content of 27.5 wt.%; and curve C, film-coated seed wetted for 48 hours to a water content of 27.5 wt.%) results in a faster germination than seed that is only coated but has not been subjected to controlled wetting (curve A, film-coated seed). Example 3

For the third example OSR (Brassica napus) seeds of cultivar 43A56 were used. The seed was coated in a 30 cm rotary coater with spinning disc. The batch size was 500 g. A mixture was made of film coat formulation Disco Agroblue L204 (commercially available from Incotec), and Cruiser^® OSR (commercially available from Syngenta) in a weight ratio of 10:17.2. The mixture was applied in the coating machine at such a dose that the Cruiser^® dose was 17.2 g/kg seed. The seed batch was subsequently dried in a seed dryer at 35 °C for 0.5 hrs. The resulting moisture content was measured with an oven protocol (4 hours at 130 °C) and was 5.03 wt.% based on total wet seed weight.

Based on the determined water content (5.03%) and the target resulting water content after treatment (38.0 wt.%) the water quantity to be added in the wetting step was calculated using the equation described in Example 1. With a seed moisture content after film coating and drying of 5.03 wt.% and a target moisture content of 38.0 wt.%, 265.9 g water had to be added to 500 g seed.

The coated seed quantity of 500 g was poured into a container with airtight lid. The calculated quantity of water was added and the lid was placed on the container. The container was shaken in order to distribute the water in the seed. The container was than placed at 30 °C for 24 hours. During this period the seed container was manually turned upside down and back two times per 24 hours to redistribute the water uniformly. After the wetting period all the added water had been absorbed.

Germination conditions were 20 days dark 5 °C on top of filter paper saturated with water. Each 24 hours germination counts were made in order to determine the germination characteristics The germination results of this Example are shown in the cumulative germination curve of Figure 4, wherein the percentage of germinated seed is illustrated as a function of time. This figure demonstrates that seed treated with the method of the invention (curve 1, film-coated seed wetted for 24 hours to a water content of 38.0 wt.%) results in a faster germination than seed that is only coated but has not been subjected to controlled wetting (curve 2, film-coated seed).

Claims

1. Method for preparing a coated seed, comprising providing a non-germinated seed and

a) coating said seed with a coating composition comprising one or more

binders and one or more active ingredients; and

b) wetting said seed in a liquid, said liquid comprising an amount of water sufficient to induce germination, wherein said amount of water is such that essentially all the water is absorbed by the seed prior to germination of said seed.

2. Method according to claim 1, wherein the water activity of the seed at the end of step b) is 0.95 or more, preferably 0.98 or more, more preferably in the range of 0.99-1.0.

3. Method according to claim 1 or 2, wherein the amount of water 20-50 wt.% based on total wet seed weight, preferably 25-40 wt.% based on total wet seed weight, more preferably 30-35 wt.% based on total wet seed weight.

4. Method according to any one of claims 1-3, wherein said amount of water is such that 95-100 wt.% of the amount of water used for wetting is absorbed by the seed prior to germination of said seed, preferably 98-100 wt.%, more preferably 100 wt.%.

5. Method according to any one of claims 1-4, wherein said seed is coated before said seed is wetted.

6. Method according to any one of claims 1-5, wherein said one or more binders are selected from the group consisting of polyvinyl acetates, polyvinyl alcohols, hydroxypropyl methyl cellulose, polysaccharides (such as starch), proteins, polyethylene glycol, and polyvinyl pyrrolidones.

7. Method according to any one of claims 1-6, wherein the amount of one or more binders is in the range of 0.3-30 g per kg of the seed, preferably 0.5-10 g per kg of the seed, more preferably 1-6 g per kg of the seed.

8. Method according to any one of claims 1-7, wherein said one or more active ingredients are selected from the group consisting of fungicidal agents, bactericidal agents, insecticidal agents, nematicidal agents, disinfectants, micro-organisms, rodent killers, herbicides, attracting agents, repellent agents, plant growth regulators, nutrients, plant hormones, minerals, plant extracts, acaricides or miticides, molluscicides, germination stimulants, pheromones, biological preparations, chitosan, and chitine-based preparations.

9. Method according to any one of claims 1-8, wherein the amount of one or more active ingredients is in the range of 0.001-200 g per kg of the seed.

10. Method according to any one of claims 1-9, wherein said seed is selected from the order of Monocotyledoneae, preferably said seed is rice seed, more preferably said rice seed is selected from the group consisting of Oryza sativa japonica, Oryza glaberrima javanica, Oryza sativa indica, Zizania palustris, and hybrids thereof.

11. Method according to any one of claims 1-10, wherein said seed is selected from the order of Dicotyledoneae, preferably said seed is carrot

(Daucus carota) seed.

12. Method according to any one of claims 1-11, wherein said wetting step is performed for a period in the range of 5 minutes to 72 hours, preferably for a period in the range of 10 minutes to 48 hours.

13. Method according to any one of claims 1-12, wherein said wetting step is performed at 5-40 °C, preferably 25-30 °C in case of rice seed and 15-20 °C in case of carrot seed.

14. Method according to any one of claims 1-13, wherein said seed is subjected to an incubation step after said wetting.

15. Seed obtainable by the method according to any one of claims 1-14.