PH12015501388B1 - Use of tetramic acid derivatives on plants to control flowering - Google Patents

Abstract

The use of compounds of the formulae (I) and (II) for modulating flowering in plants, more preferably for delaying the time to flowering and/or increasing the duration of flowering.

Description

in plants. Such delay in the time to flowering is measurable in comparison with plants untreated with such tetramic acid derivatives. Preferably, the delay in the time to flowering is at least 1 day, most preferably at least 2 days, at least 3 days, at least 4 days, at least 5 days, at least 6 days, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, at least 12 days, at least 13 days, at least 14 days, at least 1 5 days, at least 16 days, at least 17 days, at least 18 days, at least 19 days, at least 20 days.

According to another preferred embodiment, the invention relates to the use of tetramic acid derivatives of formula (I) or (II) for increasing the duration of flowering in plants. Such increase in the duration of flowering is measurable in comparison with plants untreated with such tetramic acid derivatives.

Preferably, the increase in the duration of flowering at least 1 day, most preferably at least 2 days, at least 3 days, at least 4 days, at least 5 days, at least 6 days, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, at least 12 days, at least 13 days, at least 14 days, at least 15 days, at least 16 days, at least 17 days, at least 18 days, at least 19 days, at least 20 days.

Duration of flowering may have different meanings. In plants having one single flower, it may mean the time elapsed between the opening of the flower bud until the time when the flower withers. In plants having more than one flower, including in plants having inflorescences such as panicles, the duration of flowering is preferably understood in the context of the present invention as the time elapsed between the moment when the first flower bud of the plant or of the first inflorescence opens and the time when the last flower bud of the plant or of the last inflorescence opens. Preferably, the duration of flowering is understood as the time elapsed between the moment when 5% of all flower buds of the plant or of all inflorescences have opened and the moment when 95% of all flower buds of the plant or of all inflorescences have opened. Most preferably, the duration of flowering is understood as the time elapsed between the moment when 10%) of all flower buds of the plant or of all inflorescences have opened and the moment when 90% of a

11 flower buds of the plant or of all inflorescences have opened. A preferred inflorescence is a panicle.

Emphasis is given to compound of the formula (I).

Emphasis is also given to compound of the formula (IT).

The plants on which the invention can be applied include for example the following types of plants: turf, vines, cereals, for example wheat, barley, rye, oats, rice, maize and millet/sorghum; beet, for example sugar beet and fodder beet; fruits, for example pome fruit, stone fruit and soft fruit, for example apples, pears, plums, peaches, almonds, cherries and berries, for example strawberries, raspberries, blackberries; legumes, for example beans, lentils, peas and soybeans; oil crops, for example oilseed rape, mustard, poppies, olives, sunflowers, coconuts, castor oil plants, cacao and peanuts; cucurbits, for example pumpkin/squash, cucumbers and melons; fibre plants, for example cotton, flax, hemp and jute; citrus fruit, for example oranges, lemons, grapefruit and tangerines; vegetables, for example spinach, lettuce, asparagus, cabbage species, carrots, onions, tomatoes, potatoes and bell peppers;

Lauraceae, for example avocado, Cinnamomum, camphor, or else plants such as tobacco, nuts, coffee, aubergine, sugar cane, tea, pepper, dJrapevines, hops, bananas, latex plants and ornamentals, for example flowers, shrubs, deciduous trees and coniferous trees. This enumeration is no limitation.

Preferably, the plants on which the invention can be applied are cereals, most preferably wheat, rice or maize. A preferred plant for applying the invention is rice, Oryza sativa.

Preferably, the plants on which the invention can be applied are plant varieties which are used as parents for the production of hybrid varieties. Such parents for the production of hybrid varieties can be either the male-fertile, pollen-providing, parent plants, i.e. normal plants that are not male-sterile, hereinafter described as the male-fertile parent plants, or the male-sterile female parent plants. Preferably, the plants on which the invention can be applied are the male-fertile parent plants.

Under certain conditions, it way happen that the tetramic acid derivatives of formula (I) or (II) are selectively not effective on the male-sterile, female plants, or less effective than on the male-fertile parent plants. Accordingly, in a preferred embodiment, the tetramic acid derivatives of formula (I) or (II) are not delaying, or only slightly delaying, the time to flowering of the male-sterile, female plants.

According to another embodiment, the tetramic acid derivatives of formula (I) or (II) are not increasing, or slightly increasing, the duration of flowering of the male-sterile, female plants. Such feature may be of particular interest when hybrid varieties, in particular hybrid rice varieties, are produced in fields containing alternated rows of male-fertile parent plants, and rows of male-sterile, female, parent plants. In such situations, the tetramic acid derivatives of formula (I) or (II) can be applied on the whole hybrid variety production field to delay the time to flowering and/or increase the duration of flowering of the male-fertile parent plants, without affecting the time to flowering and/or the duration of flowering of the male-sterile female parent plants.

Accordingly, the invention relates to a method for synchronising the flowering time of male-fertile parent plants, and of male-sterile female parent plants in a production field of hybrid varieties comprising a step of applying a tetramic acid derivatives of formula (I) or (II) on the whole field, thereby delaying the time to flowering and/or increasing the duration of flowering of the male-fertile, parent plants without affecting the time to flowering and/or the duration of flowering of the male-sterile female parent plants.

Preferably, such method is applied on hybrid varieties production fields when the male-fertile parent plants are at a more advanced developmental stage than the male-sterile female parent plants, which may result in asynchronous flowering of the two types of parent plants.

Alternatively, when tetramic acid derivatives of formula (I) or (II) are effective on both the male- fertile parent plants and the male-sterile female parent plants, the invention relates to a method for synchronising the flowering time of male-fertile parent plants and of male-sterile female parent plants in a production field of hybrid varieties comprising a step of applying a tetramic acid derivatives of formula (I) or (II) on the field only on the rows of the parent plants in need of having a delay of its time to

BN EE E—— EEE flowering and/or an increase of its duration of flowering, thereby delaying the time to flowering and/or increasing the duration of flowering of the parent plants in need of such effect, i.e. the advanced parent, without affecting the time to flowering and/or the duration of flowering of the other parent plants, i.e. the late parent.

Synchrony of flowering refers to a period of time during which the male-fertile, parent plants and the male-sterile, female, parent plants both have opened flowers in mature stage, i.e. they have a synchronous flowering, thereby allowing the male-fertile parent plants to pollinate the male-sterile, female, parent plants so as to generate seeds of the hybrid variety.

According to the invention, the use of the tetramic acid derivatives can be made at various application rates. Preferred application rates are generally between 1 g of tetramic acid derivative per hectare of field (1 g/ha) and 500 g/ha, more preferably between 10 g/ha and 200 g/ha, even more preferably, between 30 g ha and 100 g/ha.

For the modulation, more preferably the delay, of the time to flowering, the use of the tetramic acid derivatives is preferably made at application rates between 30 g/ha and 100 g/ha, more preferably between 40 g/ha and 100 g/ha, between 50 g/ha and 100 g/ha, 60 g/ha and 100 g/ha, between 70 g/ha and 100 g/ha, between 80 g/ha and 100 g/ha, or between 90 g/ha and 100 g/ha. A preferred application rate is 72 g/ha.

Another preferred application rate is 96 g/ha.

For the modulation, more preferably the increase, of the duration of flowering, the use of the tetramic acid derivatives is preferably made at application rates between 30 g ha and 100 g ha, more preferably between 40 g/ha and 100 g/ha, between 50 g/ha and 100 g/ha, 60 g/ha and 100 g/ha, between 70 g/ha and 100 g/ha, between 80 g/ha and 100 g/ha, or between 90 g/ha and 100 g/ha. A preferred application rate is 48 g/ha.

Another preferred application rate is 72 g/ha. Another preferred application rate is 96 g/ha.

When the invention is used on cereal plants, application of the tetramic acid derivatives is preferably made after initiation of the panicle development (also referred in the art as panicle initiation). The development of the panicle of a cereal plant starts when the panicle starts growing and becomes visible to a person skilled in the art and ends when it stops growing and when the first flower opens.

The initiation of the panicle development therefore corresponds to the moment when the panicle starts growing and becomes visible to a person skilled in the art. The development of the panicle may be measured in time unit, e.g. days, or in length unit, e.g. millimetres (mm). More preferably, the application of the tetramic acid derivatives is done more than one day after initiation of the panicle development, but preferably before the start of flowering. More preferably, the application of the tetramic acid derivatives is done before the panicle has undergone hal of its complete development, even more preferably before the panicle has undergone a quarter of its complete development.

When the cereal is a rice plant, the panicle development is measured according to the stages defined by the International Rice Research Institute (IRRI) as described in the table shown in Example 1 hereafter.

Accordingly, the application of the tetramic acid derivatives on rice plants is preferably done after the panicle has reached stage 3, more preferably when the panicle has reached stage 4. A preferred time of application is when the panicle has reached a length comprised between 2 mm and 10 mm, most preferably when the panicle has reached a length comprised between 3 mm and 5 mm.

More than one application of the tetramic acid derivatives may be done on the plants to modulate the time to flowering and/or the duration of flowering.

When more than one application are made, the first application is preferably as described above.

Additional applications may preferably be made 5 days after the first application, more preferably 10 days after the first application.

For the modulation, more preferably the delay, in the time to flowering, the use of the tetramic acid derivatives is preferably made in two separate applications. Preferably, a first application is made as described above, and a second application is made 10 days thereafter. In the case of the use of the tetramic acid derivatives on rice plants, the first application is preferably made at stage 3 or 4 of the panicle development, and a second application is preferably made 10 days later, which amounts to about stage 6 of the panicle development. For delaying the time to flowering in rice plants, the two applications are preferably made at a dose of 72g ha of the tetramic acid derivatives. For the modulation, more preferably the increase, in the duration of flowering, the use of the tetramic acid derivatives is preferably made in two separate applications. Preferably, a first application is made as described above, and a second application is made 10 days thereafter. In the case of the use of the tetramic acid derivatives on rice plants, the first application is preferably made at stage 3 or 4 of the panicle development, and a second application is preferably made 10 days later, which amounts to about stage 6 of the panicle development. For delaying the time of flowering in rice plants, the two applications are preferably made at a dose of 72g/ha of the tetramic acid derivatives.

The active compounds can be converted into the customary formulations, such as solutions, emulsions, wettable powders, water- and oil-based suspensions, powders, dusts, pastes, soluble powders, soluble granules, granules for broadcasting, suspoemulsion concentrates, natural compounds impregnated with active compound, synthetic substances impregnated with active compound, fertilizers and also microencapsulations in polymeric substances.

These formulations are produced in a known manner, for example by mixing the active compounds with extenders, that is, 1ligquid solvents, and/or solid carriers, optionally with the use of surfactants, that is to say emulsifiers and/or dispersants, and/or foam-formers.

The formulations are prepared either in suitable facilities or else before or during application.

Suitable for use as auxiliaries are substances which are suitable for imparting to the composition itself and/or to preparations derived therefrom (for example spray liquors, seed dressings) particular properties such as certain technical properties and/or also particular biological properties. Typical suitable auxiliaries are: extenders, solvents and carriers.

Suitable extenders are, for example, water, polar and nonpolar organic chemical liquids, for example from the classes of the aromatic and non-aromatic hydrocarbons

-_———_——————,,————_—,—_—_—_—_—_—™MS_ (such as paraffins, alkylbenzenes, alkylnaphthalenes, chlorobenzenes), the alcohols and polyols (which, if appropriate, may also be substituted, etherified and/or esterified), the ketones (such as acetone, cyclohexanone), esters (including fats and oils) and (poly) ethers, the unsubstituted and substituted amines, amides, lactams (such as N-alkylpyrrolidones) and lactones, the sulphones and sulphoxides (such as dimethyl sulphoxide).

If the extender used is water, it is also possible to employ, for example, organic solvents as auxiliary solvents. Essentially, suitable liquid solvents are: aromatics such as xylene, toluene or alkylnaphthalenes, chlorinated aromatics and chlorinated aliphatic hydrocarbons such as chlorobenzenes, chloroethylenes or methylene chloride, aliphatic hydrocarbons such as cyclohexane or paraffins, for example petroleum fractions, mineral and vegetable oils, alcohols such as butanol or glycol and also their ethers and esters, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, strongly polar solvents such as dimethyl sulphoxide, and also water.

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According to the invention, a carrier is a natural or synthetic, organic or inorganic substance which may be solid or liquid and with which the active compounds are mixed or bonded for better applicability, in particular for application to plants or plant parts. The solid or liquid carrier is generally inert and should be suitable for use in agriculture.

Suitable solid carriers are: for example ammonium salts and ground natural minerals such as kaolins, clays, talc, chalk, quartz, attapulgite, montmorillonite or diatomaceous earth, and ground synthetic materials such as highly- disperse silica, alumina and silicates; suitable solid carriers for granules are: for example, crushed and fractionated natural rocks such as calcite, marble, pumice, sepiolite and dolomite, and also synthetic granules of inorganic and organic meals, and granules of organic material such as paper, sawdust, coconut shells, maize cobs and tobacco stalks; suitable emulsifiers and/or foam-formers are: for example, nonionic and anionic emulsifiers, such as polyoxyethylene fatty acid esters, polyoxyethylene fatty alcohol ethers, for example alkylaryl polyglycol ethers, alkylsulphonates, alkyl ee —————————————————————— ’ sulphates, arylsulphonates and also protein hydrolysates; suitable dispersants are nonionic and/or ionic substances, for example from the classes of the alcohol-POE and/or -POP ethers, acid and/or POP POE esters, alkylaryl and/or POP POE ethers, fat and/or POP

POE adducts, POE- and/or POP-polyol derivatives, POE- and/or POP-sorbitan or -sugar adducts, alkyl or aryl sulphates, alkyl- or arylsulphonates and alky I or aryl phosphates or the corresponding PO-ether adducts.

Furthermore, suitable oligo- or polymers, for example those derived from vinylic monomers, from acrylic acid, from EO and/or PO alone or in combination with, for example, (poly)alcohols or (poly)amines. It is also possible to employ lignin and its sulphonic acid derivatives, unmodified and modified celluloses, aromatic and/or aliphatic sulphonic acids and their adducts with formaldehyde.

Tackifiers such as carboxymethylcellulose and natural and synthetic polymers in the form of powders, granules or latices, such as gum arabic, polyvinyl alcohol and polyvinyl acetate, as well as natural phospholipids such as cephalitis and 1lecithins, and synthetic phospholipids, can be used in the formulations.

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It is possible to use colourants such as inorganic pigments, for example iron oxide, titanium oxide and

Prussian Blue, and organic colourants such as alizarin colourants, azo colourants and metal phthalocyanine colourants, and trace nutrients such as salts of iron, manganese, boron, copper, cobalt, molybdenum and zinc.

Other possible additives are perfumes, mineral or vegetable, optionally modified oils, waxes and nutrients (including trace nutrients), such as salts of iron, manganese, boron, copper, cobalt, molybdenum and zinc.

Stabilizers, such as low-temperature stabilizers, preservatives, antioxidants, light stabilizers or other agents which improve chemical and/or physical stability may also be present.

The formulations generally comprise between 0.01 and 98% by weight of active compound, preferably between 0.5 and 90%.

In a preferred embodiment of the invention, to boost the activity, a penetrant is additionally added to the crop protection compositions. Suitable penetrants also include, for example, substances which promote the availability of the compounds of the formula (I) or (II) in the spray coating. These include, for example, mineral or vegetable oils. Suitable oils are all mineral or vegetable - optionally modified - oils which are usually used in agrochemicai compositions. Mention may be made, by way of example of, sunflower oil, rapeseed oil, olive oil, castor oil, colza oil, maize seed oil, cotton seed oil and soya bean oil, or the esters of said oils. Preference is given to rapeseed oil, sunflower oil and their methyl and ethyl esters, in particular to rapeseed oil methyl esters.

The concentration of penetrant in the compositions according to the invention can be varied within a wide range. In the case of a formulated crop protection composition it is generally from 1 to 95%> by weight, preferably from 1 to 55% by weight, particularly preferably 15-40% by weight. In the ready-to- use compositions (spray liquors), the concentration is generally between 0.1 and 10 g/l, preferably between 0.5 and 5 g/1.

The active compounds according to the invention can furthermore be present in their commercially available formulations and in the use forms, prepared from these

. formulations, as a mixture with synergists. Synergists are compounds which increase the action of the active compounds, without it being necessary for the synergist added to be active itself.

The active compounds according to the invention can furthermore be present in their commercially available formulations and in the use forms, prepared from these formulations, as mixtures with inhibitors which reduce degradation of the active compound after use in the environment of the plant, on the surface of parts of plants or in plant tissues.

The active compound content of the use forms prepared from the commercially available formulations can vary within wide limits. The active compound concentration of the use forms can be from 0.00000001 to 95% by weight of active compound, preferably between 0.00001 and 1% by weight.

Application occurs in a customary manner, suitable for the use forms.

All plants and plant parts can be treated in accordance with the invention. By plants are understood here all plants and plant populations such as desired and undesired wild plants or crop plants (including naturally occurring crop plants). Crop plants can be plants which can be obtained by conventional breeding and optimization methods or by biotechnological and genetic engineering methods or combinations of these methods, including the transgenic plants and including the plant varieties which can or cannot be protected by varietal property rights.

Examples which may be mentioned are the important crop plants, such as cereals (wheat, rice), maize, soya beans, potatoes, sugar beet, tomatoes, peas and other vegetable species, cotton, tobacco, oilseed rape and also fruit plants (with the fruits apples, pears, citrus fruits and grapes). Plant parts are to be understood as meaning all above-ground and below-ground parts and organs of plants, such as shoot, leaf, flower and root, examples which may be mentioned being leaves, needles, stalks, stems, flowers, fruit bodies, fruits, seeds, roots, tubers and rhizomes.

The plant parts also include harvested material, and vegetative and generative propagation material, for example cuttings, tubers, rhizomes, offsets and seeds.

IB — ---- mk :-———_—_—_,,_m—————— ee ——

Treatment according to the invention of the plants and plant parts with the active compounds is carried out directly or by allowing them to act on the surroundings, environment or storage space by the

Customary treatment methods, for example by immersion, spraying, evaporation, fogging, scattering, painting on, injecting and, in the case of propagation material, in particular in the case of seeds, also by applying one Or more coats.

As already mentioned above, it is possible to treat all plants and their parts according to the invention. In a preferred embodiment, wild plant species and plant cultivars, or those obtained by conventional biological breeding methods, such as crossing or protoplast fusion, and also parts thereof, are treated. In a further preferred embodiment, transgenic plants and plant cultivars obtained by genetic engineering, if appropriate in combination with conventional methods (Genetically Modified Organisms), and parts thereof are treated. The terms "parts" or "parts of plants" or "plant parts" have been explained above.

Particularly preferably, plants of the plant cultivars which are in each case commercially available or in use

USE OF TETRAMIC ACID DERIVATIVES = ion

ON PLANTS TO CONTROL FLOWERING 5 ’ *

The present invention relates to the use of knowh i « tetramic acid derivatives on plants to modulate flowering, more specifically the time to flowering and the duration of flowering.

Background information

There are many advantages, in plant breeding and plant production, of being able to control the time at which plants flower and the duration of such flowering.

However, one main advantage of such possibility is in the production of seeds of hybrid varieties.

Hybrid varieties are varieties obtained from the cross between two distinct varieties of a same plant species.

One of their main advantages is to benefit a significant higher yield compared to inbred varieties (i.e. varieties obtained from self-pollination or crosses between plants of the same variety). This biological phenomenon is known as heterosis or hybrid vigor. Because of this advantage, hybrid varieties are are treated according to the invention. Plant cultivars are to be understood as meaning plants having new properties ("traits") and which have been obtained by conventional breeding, by mutagenesis or by recombinant

ON A techniques. They can be cultivars, biotypes or genotypes.

Depending on the plant species or plant cultivars, their location and growth conditions (soils, climate, vegetation period, nutrition), the treatment according to the invention may also result in superadditive ("synergistic") effects. Thus possible are, for example, reduced application rates and/or a widening of the activity spectrum and/or an increase of the activity of the compounds and compositions usable according to the invention, better plant growth, increased tolerance to high or low temperatures, increased tolerance to drought or to water or soil salt content, increased flowering, easier harvesting, accelerated maturation, higher harvest yields, higher quality and/or higher nutritional value of the harvested products, increased storability and/or processability of the harvested products, which exceed the effects normally to be expected.

The preferred transgenic plants or plant cultivars (i.e. those obtained by genetic engineering) which are to be treated according to the invention include all plants which, in the genetic modification, received genetic material which imparts particularly advantageous useful properties ("traits") to these plants. Examples of such properties are better plant growth, increased tolerance to high or low temperatures, increased tolerance to drought or to water or soil salt content, increased flowering, easier harvesting, accelerated maturation, higher harvest yields, higher quality and/or a higher nutritional value of the harvested products, better storability and/or processability of the harvested products.

Further and particularly emphasized examples of such properties are a better defence of the plants against animal and microbial pests, such as against insects, mites, phytopathogenic fungi, bacteria and/or viruses, and also increased tolerance of the plants to certain herbicidally active compounds. Examples of transgenic plants which may be mentioned are the important crop plants, such as cereals (wheat, rice), maize, soya beans, potatoes, sugar beet, tomatoes, peas and other types of vegetable, cotton, tobacco, ollseed rape and also fruit plants (with the fruits apples, pears, citrus fruits and grapes), with particular emphasis being given to maize, soya beans, potatoes, cotton, tobacco and oilseed rape. Traits that are emphasized in particular are increased defence of the plants against insects, arachnids, nematodes and slugs and snails by toxins formed in the plants, in particular those formed in the plants by the genetic material from Bacillus thuringiensis (for example by the genes Cryla(a),

CrylA(b), CrylA(c), CryIIA, CryIIIA. CryIIIB2, Cry9gc,

Cry2Ab, Cry3Bb and CryIF and also combinations thereof) (hereinbelow referred to as "Bt plants"). Traits that are also particularly emphasized are the increased defence of the plants against fungi, bacteria and viruses by systemic acquired resistance (SAR) , systemin, phytoalexins, elicitors and also resistance genes and correspondingly expressed proteins and toxins. Traits that are furthermore particularly emphasized are the increased tolerance of the plants to certain herbicidally active compounds, for example imidazolinones, sulphonylureas, glyphosate or phosphi nothricin (for example the "PAT" gene). The genes which impart the desired traits in question can also be present in combinations with one another in the transgenic plants. Examples of "Bt plants" which may be mentioned are maize varieties, cotton varieties, soya bean varieties and potato varieties which are sold under the trade names YIELD GARD® (for example maize, cotton, soya beans), Knockout® (for example maize),

StarLink® (for example maize), Bollgard® (cotton),

Nucotn® (cotton) and NewLeaf® (potato). Examples of herbicide -tolerant plants which may be mentioned are maize varieties, cotton varieties and scya bean varieties which are sold under the trade names Roundup

Ready® (tolerance against glyphosate, for example maize, cotton, soya beans), Liberty Link® (tolerance against phosphinothricin, for example oilseed rape),

IMI® (tolerance against imidazolinones) and STS® (tolerance against sulphonylurea, for example maize).

Herbicide-resistant plants (plants bred in a conventional manner for herbicide tolerance) which may be mentioned include the varieties sold under the name

Clearfield® (for example maize). Of course, these statements also apply to plant cultivars having these genetic traits or genetic traits still to be developed, which plants will be developed and/or marketed in the future.

The invention is illustrated by the examples below.

However, the invention is not limited to the examples.

Example 1: Design of experiments conducted with rice

Experiments have been conducted either with one rice variety usually used as a male line in hybrid rice production, i.e. a normal male-fertile rice line, or with two male-sterile rice varieties used as female lines in hybrid rice production.

Rice seeds were germinated in a nursery with a seed density of 40g/m’.

Field for rice cultivation has been leveled carefully to avoid any low or high spot, which might affect uniform plant growth. Rice plants were transplanted 21 -23 days after sowing to blocks consisting of 36 plots (in 4 m? plots), each plot being made of 2 subplots.

Each subplot has a size of 2 m? and contains 50 plants

IB EE —— (one plant per hill), planted with a distance of 20 cm in both directions. One subplot in each plot serves as untreated control.

Rice plants were then grown under good agronomic practices.

Developmental stages of the rice plants were monitored based on panicle initiation as described in the following table, issued by the International Rice

Research Institute (IRRI, Philippines):

Developmental Stage Approx. days | Approx. panicle before flowering Length {mm} [eee ew

A first application of spirotetramat was performed at stage 3 or 4, at a panicle primordia size of around 3 to 5 mm. When a second application was performed, it was done 10 days after the first application, i.e. at about stage 6.

Spirotetramat (Movento® 150 OD formulation) was sprayed on the whole plants using precise spray equipement, and spray drift of chemicals was prevented by using a suitable plastic drift guard during application to separate the untreated subplot to the treated omnes.

The time to flowering has been determined as follows:

From the start of panicle emergence stage (or heading) , primary (or 1°) and secondary (2™) tillers of 10 randomly selected plants of a subplot have been monitored for flowering. Time to flowering was determined when approximately 50% of the total number of monitored panicles have flowered/headed (at least 50%0 of panicle length have been exserted and/or has shown part of the panicles that has bloomed) .

Duration of flowering was determined from the time when approximately 10%> of the flowers of a panicle have opened (bloomed) until when 90 $s of the flowers of a panicle have opened (bloomed).

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Example 2: Effect of spirotetramat on the time to flowering of a male-fertile rice variety 2.1. Effect of one application of Spirotetramat on the time to flowering

Spirotetramat has been applied once (stage 3-4) at three different doses (48 g ha, 72 g ha and 96 g/ha).

The time to flowering is expressed as a number of days after sowing (DAS).

Treatment Dose rate Time to Flowering Delay in flowering (g/ha) (DAS) vs untreated (days)

Untreated 0 86 0

Spirotetramat 43 87 +

Spirotetramat n 96 +10

Spirotetramat 96 95 +9

Results of the above table show that spirotetramat has an effect on the time to flowering in rice plants. This effect is a delay in flowering. Such delay is limited when a dose of 48 g ha is applied, but doses of 72 g/ha and 96 g/ha are able to increase the time of flowering by about 10 days. 2.2. Influence of the time of application

Spirotetramat has been applied at stage 3-4, or 10 days after first application (stage 6) with two different

BN EE — doses (48 g/ha and 72 g/ha). The time to flowering is expressed as a number of days after sowing (DAS).

Treatment Doseraic ~~ Applicationtime Timeto flowering ~~ Delayin (g/ha) (development (DAS) flowering vs stage) unireated (days)

Untreated 0 86 0

Spirotetramat 48 34 §7 +

Spirotetramat 43 0 86 0

Spirotetramat 1 34 9% +0

Spirotetramat n 6 86 0

Results show that the effect of Spirotetramat on the time to flowering is obtained when the rice plants are treated at stage 3-4. No effect has been observed when the rice plants are treated at stage 6. 2.3. Influence of the number of applications

Spirotetramat has been applied once (stage 3-4) or twice (10 days after first application = stage 6) at two different doses (48 g/ha and 72 g/ha). The time to flowering is expressed as a number of days after sowing (DAS) .

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Treatment Dose rate Application time ~~ Time to flowering Delay in (g/ha) (development (DAS) flowering vs stage) untreated (days)

Untreated 0 86 0

Spirotetramat 48 © 34 87 +1

Spirotetramat 48 34+6 87 +]

Spirotetramat 72 3-4 96 +10

Spirotetramat 72 3-4+6 100 +14

Results confirm that the effect of Spirotetramat on delaying the time to flowering is limited when a dose of 48 g/ha is applied (+1 day), but that doses of 72 g/ha are able to increase the time to flowering by about 10 days. A second treatment at the same dose 10 days after the first one has no additional effect at the dose of 48 g/ha, but is able to further increase the delay at the dose of 72 g/ha (+14 days Vs. untreated control, and +4 days vs. only the first treatment).

Example 3: Effect of spirotetramat on the duration of ;flowering of a male-fertile rice variety 2.1. Effect of one application of Spirotetramat on the duration of flowering

Spirotetramat has been applied once (stage 3-4) at three different does (48 g/ha, 72 g/ha and 96 g/ha).

being used more and more around the world, and hybrid varieties are created in more and more crop species (maize, rice, wheat, canola...).

However, the production of hybrid seeds requires that one of the varieties used to produce them be prevented from generating viable pollen, so as to allow the pollen of the second variety to pollinate its female reproductive organs, from which the hybrid seeds are obtained. Breeders have been able to isolate plant varieties having non-viable male reproductive organs, thereby being male-sterile plants, which can be used for crossing with other varieties to obtain hybrid seeds. Such male-sterile plants are, for example, plants bearing a cytoplasmic male sterility (CMS) or a nuclear male sterility (NMS).

Using such plants, breeders are able to produce hybrid seeds by crossing two distinct varieties of interest, one of which being male-sterile, i.e. which does not produce viable pollen. For doing so, plants of the two varieties are usually sown in a same field according to a mixed or alternated sowing plan, and grown at the same time in the field so that the pollen of one

ET —————————————————————————————

Treatment Dose rate Duration of flowering Increase in duration of (g/ha) (days) flowering vs untreated (days)

Untreated 0 6 0

Spirotetramat 48 13 +7

Spirotetramat 72 16 +10

Spirotetramat 96 16 +10)

Results of the above table show that spirotetramat has an effect on the duration of flowering in rice plants.

This effect is an increase in the duration of flowering. Such increase is obtained at all doses tested, and doses of 72 g a and 96 g ha are able to increase the time of flowering up to about 10 days. 2.2. Influence of the time of application

Spirotetramat has been applied at stage 3-4, or 10 days after first application (stage 6) with two different doses (48 g ha and 72 g ha).

IB -_—

Treatment Dose rate Application time Duration of Increase in (g/ha) (development flowering duration of stage) (days) flowering vs untreated (days)

Untreated 0 6 0

Spirotetramat 48 3-4 13 +7

Spirotetramat 48 6 6 0

Spirotetramat 72 3-4 16 +0

Spirotetramat 72 6 7 +1

Results show that the effect of Spirotetramat on the duration of flowering is obtained when the rice plants are treated at stage 3-4. No effect, or very limited effect, has been observed when the rice plants are treated at stage 6. 2.3. Influence of the number of applications

Treatment Dose rate Application time Duration of Increase in (g/ha) (development flowering duration of stage) (days) flowering vs untreated (days)

Untreated 0 6 0

Spirotetramat 48 3-4 13 +7

Spirotetramat 43 3-4+6 13 , tT

Spirotetramat 72 3-4 16 +10

Spirotetramat 72 3-4+6 21 +135

Results show that the effect of Spirotetramat on the duration of flowering is not further increased when a dose of 48 g/ha is applied a second time, but that a second treatment at doses of 72 g ha is able to significantly increase the duration of flowering by about 15 days (+5 days vs. only the first treatment) .

Example 4: Effect of spirotetramat on the time to flowering of a male-sterile, femaie, rice variety

The effect of spirotetramat has been tested on two male-sterile rice varieties used as female lines in hybrid rice production.

No effect on the time to flowering has been observed on these two male-sterile, female, rice lines, or only a much lower effect than the effect observed on the pollen-producing male fertile rice lines. This observation has been made at all application rates tested (48 g a, 72 gha and 96 g/ha) and at all application times tested (with treatment at stage 3-4 only, at stage 6 only, or with a double treatment once at stage 3-4 and a second one at stage 6).

variety pollinates the female reproductive organs of plants of the male-sterile variety.

However, one of the problems encountered by hybrid seed producers 1s to make sure that flowers of both varieties get mature at the same time, or that at least a sufficient time frame is allowed during which flowers of both varieties are mature together. Indeed, if flowers of one variety get mature, e.g. the flowers of the pollen-producing variety start releasing pollen, while flowers of the other variety are not yet mature, e.g. flowers of the male-sterile plant have immature female organs, the cross between the two varieties will not be possible and no hybrid seed will be obtained. A reverse situation leads to the same result. Considering that reproductive organs maturity usually occurs about two to three months after sowing, that different varieties generally have different maturity rates, and that for a given variety, time of flower maturity can be significantly influenced by the environment, such as e.g. climatic conditions, flowering synchrony is not a given and hybrid seed production is constantly put at risk.

In order to optimize their chances to have flowering synchronicity, hybrid seed producers calculate precisely the time of sowing (or transplanting for transplanted crops) of both varieties, but still have the risk that the climatic conditions or some other environmental stresses will affect the normal time to flowering and/or duration of flowering of one or both varieties. Some have been trying to apply certain compounds such as urea or 2,4-D to delay flowering time by 1 or 2 days (Huang et al., 1994, in Hybrid Rice

Technology, new developments and future prospects, IRR

I, Eds. SS Virmani, p 64-65;).

However, hybrid seed production is affected every year by lack of flowering synchronicity, and there still exists a need for new solutions enabling hybrid seed producers to modulate, i.e. advance r delay, flowering of the parent varie;ties of their hybrid variety.

Description of the invention

Surprisingly, it has now been found that the compounds of the formulae (I) or (II)

H

H HC N 0

N 0 No Hy — 0 CH, ——

HO © o={ 0 CH,

CH, ) 1) H,C (I) Spirotetramat are suitable to control the time to flowering and/or the duration of flowering of plants.

The compounds of the formulae (I) and (II) and their insecticidal and/or acaricidal action are known from:

WO 98/05638, WO 04/007448.

Accordingly, the present invention relates to the use of tetramic acid derivatives of formula (I) or (II) for modulating the time to flowering in plants.

Alternatively, the present invention relates to a method for modulating the time to flowering in plants, comprising a step of applying a tetramic acid derivatives of formula (I) or (II) on the plant.

According to a second embodiment, the invention relates to the use of tetramic acid derivatives of formula (I) or (II) for controlling the duration of flowering in plants. Alternatively, the present invention relates to a method for controlling the duration of flowering in plants, comprising a step of applying a tetramic acid derivatives of formula (I) or (II) on the plant.

Time to flowering shall generally be understood as the time between a certain reference time point in the plant's development as hereinafter defined, and the moment when the plant is flowering.

Flowering may have different meanings, and shall generally be understood in the context of the present invention as meaning the opening of the flowers.

Flowering may be considered at different points of time when considering a whole plant containing several flowers. For example, flowering may be considered either at the opening of the first flower, when half of the flowers are opened or when 100% of the flowers are opened. Preferably, flowering of a whole plant is considered when 50% (i.e. half) of the flowers have opened.

In plants having flowers organized as inflorescences such as panicles, flowering may mean the opening of a certain quantity of flowers in a panicle, e.g. between

BN YY _ _ 0 —_ 0% and 100%) of the flowers of a given panicle.

Preferably, flowering of a panicle is considered when 50% (i.e. half) of the flowers of a concerned panicle have opened.

The time to flowering of a plant or panicle shall be considered with a given reference time point. Such reference time point may be a development stage of the plant or the panicle, such as for example sowing, germination, soil emergence, seedling, transplanting (if applicable) or tillering for the plant, or panicle exsertion for a panicle. Time to flowering may also be measured with reference to an event occurring on the plant such as for example a treatment with a chemical compound or a stress applied to the plant. A preferred reference time point is the time of sowing.

Accordingly, time to flowering is preferably understood as being the time between sowing of the plant and flowering of either 50% of the flowers on the plant or in a given panicle.

According to a preferred embodiment, the invention relates to the use of tetramic acid derivatives of formula (I) or (II) for delaying the time to flowering

Claims (7)

Claims:

1. The use of compounds of the formulae (I) or (ITI) H N20 0 3 — 0 CH, —

H.C HO ° o={ 0 CH, CH, ) H,C (1) 3 0) on plants for modulating flowering.

2. The use of compounds of the formulae (I) or HL according to claim 1, for delaying the ey flowering. = 0 5 @ Ln od

3. The use of compounds of the formulae (I) or (IT according to claim 1, for increasing the duration of flowering.

4. The use of compounds of the formulae (I) or (II) according to anyone of claims 1 to 3, whereby the plant is a cereal.

5. The use of compounds of the formulae (I) or (II) according to claim 4, whereby the cereal is a rice plant.

6. The use of compounds of the formulae (I) or (II) according to claim 5, whereby the rice plant is a male-fertile plant.

7. A method for synchronising the flowering time of male-fertile parent plants and of male-sterile female parent plants in a production field of hybrid varieties, comprising a step of applying a tetramic acid derivatives of formula (I) or (II) on the field only on the rows of the parent plants in need of having a delay of its time to flowering and/or an increase of its duration of flowering, thereby delaying the time to flowering and/or increasing the duration of flowering of the parent plants in need of such effect, i.e. the advanced parent, without affecting the time to flowering and/or the duration of flowering of the other parent plants, i.e. the late parent.