WO2026030352A1

WO2026030352A1 - Methods and seed coatings for improving plant growth and crop yield

Info

Publication number: WO2026030352A1
Application number: PCT/US2025/039705
Authority: WO
Inventors: Ned B. Bowden
Original assignee: University of Iowa Research Foundation UIRF
Current assignee: University of Iowa Research Foundation UIRF
Priority date: 2024-07-31
Filing date: 2025-07-29
Publication date: 2026-02-05
Anticipated expiration: 2027-01-31

Abstract

The invention provides methods, coated seeds, and kits that are useful for increasing the growth and/or the harvest yield of a crop.

Description

METHODS AND SEED COATINGS FOR IMPROVING PLANT GROWTH

AND CROP YIELD

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to United States Provisional Application Number 63/677,700 that was filed on July 31, 2024. The entire content of the applications referenced above is hereby incorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with government support under AMS21SCMPIA1011-00 awarded by the United States Department of Agriculture. The government has certain rights in the invention

BACKGROUND

The worldwide population is expected to grow from its current level of 7.2B to 9.6B people by 2050 ( United Nations, Department of Economic and Social Affairs, Population Division (2013). World Population Prospects: The 2012 Revision, Highlights and Advance Tables. Working Paper No. ESA/P/WP.228; Foley JA, et al., Nature 2011;478:337-42; and Godfray HCJB, et al., Science. 2010;327:812-8). To meet the needs of the world’s growing human population, it is projected that global food production must increase 70% by 2050 (www.fao.org/fileadmin/templates/wsfs/docs/expert_paper/How_to_Feed_the_World_ in_2050.pdf). Aside from sheer population numbers, there are additional factors that will increase market demand for food production. Trends indicate that as developing countries urbanize and their economies grow, their consumption of meat and dairy products will also increase. Because the conversion of feed to livestock is inefficient (for instance, each pound of hamburger requires 52 pounds of feed grain over a cow’s lifetime; Capper JL., Animals. 2012;2: 127-43) growth in this sector creates an increasing demand for cereal crops. Biofuel production may drive cereal demands even higher. Yet the amount of land dedicated to farming has remained at 1992 levels both in the United States and worldwide, which has led to a decrease in agricultural area per capita from 0.44 hectares per capita in 1960 to 0.17 hectares per capita in 2025. Current advances in technology cannot increase the yield per acre of crops enough to feed the growing population; new innovations are needed. Solutions must be environmentally safe, nonpolluting, and should help crops survive droughts and other environmental stressors that affect their growth.

One partial solution to this problem is the application of hydrogen sulfide (H2S) to increase the growth, survival, and yields of crops. H2S is a gasotransmitter that is synthesized enzymatically in plants and used as a signaling molecule. Research in the last dozen years has repeatedly demonstrated that therapeutic amounts of H2S have dramatic effects, including increased growth of roots, protection against heat stress and drought conditions, increased overall size and mass, alleviation from freezing stress on leaves, protection from high water salinity, and prolonged fruit shelf life ( Guo H, et al., Acta Physiol Plant. 2016;38(1): 1 - 13 ; Shi H, et al., Plant Phys Biochem. 2013;71 :226-34; Hu L-Y, et al., J Agric Food Sci. 2012;60:8684- 93; Li Z-R, et al., HortScience. 2015;50(3):416-20; Li Y-J, et al., J Agric Food Chem. 2014;62: l 119-29; and Christou A, et al., J Exper Botany. 2013;64(7): 1953-66). Two of the challenges of working with H2S is that it is a low boiling point gas (boiling point = -60°C), and it is highly toxic. Exposure to levels of 2 ppm of H2S in the air can lead to negative health effects such as headaches or breathing problems for people who suffer from asthma, and exposure to 100 ppm is “immediately dangerous to life and health” (www.osha.gov/SLTC/ hydrogensulfide/ hazards.html).

The investigation of H2S in plants is a new field - much of the key work has been completed since 2007 - yet it has already been shown to have positive effects on corn, soybeans, wheat, sweet potatoes, cucumbers, strawberries, rice, spinach, tomatoes, broccoli, and kiwi (Duan B, et al., Plant Growth Regul. 2015;75:33-44; Li Z-G, et al., J Plant Phys. 2013;170:741- 7; Li ZG. Russian J Plant Phys. 2013;60:733-40; Alvarez C, et al., Arabidopsis. Plant Physiol. 2010;152(2):656-69; Bloem E, et al., J Agron Crop Sci. 2011; 197(4):311-21; Chen J, et al., J Exp Bot. 2011;62(13):4481-93; Christou A, et al., J Exp Bot. 2013;64(7):1953-66; Fang T, et al., Plant Physiol Biochem. 2014;76:44-51; Fu P, et al., L. Acta Soc Bot Pol. 2013;82(4):295- 302; Gao S-P, et al., HortScience. 2013;48(l 1): 1385-92; Garcia-Mata C, et al., New Phytol. 2010;188(4):977-84; Hou Z, et al., J Integr Plant Biol. 2013;55(3):277-89; Hu L-Y, et al., J Agric Food Chem. 2012;60(35):8684-93; Krasensky J, et al., J Exp Bot. 2012;63(4): 1593-608; Li S-P, et al., J Agric Food Chem. 2014;62(5): 1119-29; Li Z-G, et al., Acta Physiol Plant. 2012;34(6):2207-13; Lin Y-T, et al., J Plant Growth Regul. 2012;31(4):519-28; Liu J, et al., Chin Sci Bull. 2011;56(33):3547-53; Papenbrock J, et al., Plant Biol. 2007;9(5):582-8; Shi H, et al., Plant Physiol Biochem. 2014;74:99-107; Sun Y, et al., J Food, Agric Environ. 2013; 11(3 & 4, Pt. 2): 1097-100; Wang B-L, et al., Planta. 2010;231(6): 1301-9; Yadav SK. S Afr J Bot.

2010;76(2): 167-79; Zhang H, et al., Postharvest Biol Technol. 2011;60(3):251-7; Zhang H, et al., J Integr Plant Biol. 2009;51(12): 1086-94; and Zhang H, et al., Plant Growth Regul.

2009;58(3):243-50).

Carter et al. have shown that the compound GYY-4137, which slowly releases EES by hydrolysis, increased the growth of radish, peas, and lettuce plants and that the harvest yield of radishes doubled when milligram loadings of GYY-4137 were applied (Carter JM, et al., PLoS ONE 13(12): e0208732; doi.org/10.1371/journal.pone.0208732).

There is currently a need for additional methods that are useful to increase the growth and harvest yields of crops

SUMMARY

A method for increasing growth or harvest yield of a plant that grows from a seed comprising coating the seed with a compound capable of releasing EES is provided. In one embodiment, the seed is coated with the compound prior to planting. In another embodiment, the seed is coated with the compound after planting (e.g., by spraying the compound onto the planted seed or by dusting the compound onto the planted seed).

A seed having a coating that comprises a compound that is capable of releasing EES after the seed is planted is also provided.

A method for preparing a seed having a coating that comprises a compound that is capable of releasing EES after the seed is planted, comprising combining a seed and the a compound under conditions that provide the seed having a coating that comprises a compound that is capable of releasing EES after the seed is planted is also provided.

A kit comprising; one or more seeds having a coating that comprises a compound that is capable of releasing EES after the seed is planted; and packaging material containing the one or more seeds having a coating that is capable of releasing EES after the seed is planted is provided. BRIEF DESCRIPTION OF THE DRAWINGS

Figures la-le. show chemicals that are capable of releasing H2S. (a) shows chemicals that possess carbon-sulfur double or single bonds; (b) shows chemicals that possess phosphorous-sulfur double bonds; (c) shows chemicals that possess carbon-sulfur single bonds and are monosulfides, disulfides, trisulfides, or potentially higher sulfides; (d) shows chemicals that possess sulfur-nitrogen or sulfur-oxygen bonds; and (e) shows chemicals that are either metal sulfides or sulfide salts with counterions such as sodium or other appropriate cations.

Figure 2. shows an illustration of a cross-sectional view of a coated seed

Figure 3. shows an illustration of a perspective view of a coated seed Figure 4. shows an illustration of a perspective view of a coated seed DETAILED DESCRIPTION

The following definitions are used, unless otherwise described: halo or halogen is fluoro, chloro, bromo, or iodo. Alkyl, alkoxy, etc. denote both straight and branched groups; but reference to an individual radical such as propyl embraces only the straight chain radical, a branched chain isomer such as isopropyl being specifically referred to.

The term "alkyl", by itself or as part of another substituent, means, unless otherwise stated, a straight or branched chain hydrocarbon radical, having the number of carbon atoms designated (i.e., C1-8 means one to eight carbons). Examples include (Ci-C8)alkyl, (C2-Cs)alkyl, Ci-Ce)alkyl, (C2-Ce)alkyl and (C3-Ce)alkyl. Examples of alkyl groups include methyl, ethyl, n- propyl, iso-propyl, n-butyl, t-butyl, iso-butyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and and higher homologs and isomers.

The term “cycloalkyl” refers to a saturated or partially unsaturated (non-aromatic) all carbon ring having 3 to 8 carbon atoms (i.e., (C3-C8)carbocycle). The term also includes multiple condensed, saturated all carbon ring systems (e.g., ring systems comprising 2, 3 or 4 carbocyclic rings). Accordingly, carbocycle includes multicyclic carbocyles such as a bicyclic carbocycles (e.g., bicyclic carbocycles having about 3 to 15 carbon atoms , about 6 to 15 carbon atoms, or 6 to 12 carbon atoms such as bicyclo[3.1.0]hexane and bicyclo[2.1.1]hexane), and polycyclic carbocycles (e.g tricyclic and tetracyclic carbocycles with up to about 20 carbon atoms). The rings of the multiple condensed ring system can be connected to each other via fused, spiro and bridged bonds when allowed by valency requirements. For example, multicyclic carbocyles can be connected to each other via a single carbon atom to form a spiro connection (e.g., spiropentane, spiro[4,5]decane, etc), via two adjacent carbon atoms to form a fused connection (e.g., carbocycles such as decahydronaphthalene, norsabinane, norcarane) or via two non-adjacent carbon atoms to form a bridged connection (e.g., norbornane, bicyclo[2.2.2]octane, etc). Non-limiting examples of cycloalkyls include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, bicyclo[2.2.1]heptane, pinane, and adamantane.

The term “heterocyclic ring” refers to a single saturated or partially unsaturated ring that has at least one atom other than carbon in the ring, wherein the atom is selected from the group consisting of oxygen, nitrogen and sulfur; the term also includes multiple condensed ring systems that have at least one such saturated or partially unsaturated ring, which multiple condensed ring systems are further described below. Thus, the term includes single saturated or partially unsaturated rings (e.g., 3, 4, 5, 6 or 7-membered rings) from about 1 to 6 carbon atoms and from about 1 to 3 heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur in the ring. The sulfur and nitrogen atoms may also be present in their oxidized forms.

As used herein, the term "heteroatom" is meant to include oxygen (O), nitrogen (N), sulfur (S) and silicon (Si).

As used herein a wavy line “ ” that intersects a bond in a chemical structure indicates the point of attachment of the bond that the wavy bond intersects in the chemical structure to the remainder of a molecule.

The phrase “increase the growth of a plant” includes increasing the mass of the plant or the height of the plant. In one embodiment, the mass of the plant is increased by at least about 5%. In another embodiment, the mass of the plant is increased by at least about 10%. In another embodiment, the mass of the plant is increased by at least about 20%. In one embodiment, the height of the plant is increased by at least about 5%. In another embodiment, the height of the plant is increased by at least about 10%. In another embodiment, the height of the plant is increased by at least about 20%.

The phrase “increase the harvest yield of a plant” includes increasing the yield (e.g. volume or mass) of the harvested material from a plant. In one embodiment, the harvest yield of the plant is increased by at least about 1%. In another embodiment, the harvest yield of the plant is increased by at least about 3%. In another embodiment, the harvest yield of the plant is increased by at least about 10%. In another embodiment, the harvest yield of the plant is increased by at least about 20%. Suitable agricultural adjuvants and carriers that are useful in preparing the compositions of the invention are well known to those skilled in the art.

Liquid carriers that can be employed include water, toluene, xylene, petroleum naphtha, crop oil, acetone, methyl ethyl ketone, cyclohexanone, acetic anhydride, acetonitrile, acetophenone, amyl acetate, 2-butanone, chlorobenzene, cyclohexane, cyclohexanol, alkyl acetates, diacetonalcohol, 1,2-di chloropropane, diethanolamine, p-di ethylbenzene, di ethylene glycol, diethylene glycol abietate, diethylene glycol butyl ether, diethylene glycol ethyl ether, di ethylene glycol methyl ether, N,N-dimethyl formamide, dimethyl sulfoxide, 1,4-di oxane, dipropylene glycol, dipropylene glycol methyl ether, dipropyleneglycol dibenzoate, diproxitol, alkyl pyrrolidinone, ethyl acetate, 2-ethyl hexanol, ethylene carbonate, 1,1,1 -tri chloroethane, 2- heptanone, alpha pinene, d-limonene, ethylene glycol, ethylene glycol butyl ether, ethylene glycol methyl ether, gamma-butyrolactone, glycerol, glycerol diacetate, glycerol monoacetate, glycerol triacetate, glycerol triacetate, hexadecane, hexylene glycol, isoamyl acetate, isobornyl acetate, isooctane, isophorone, isopropyl benzene, isopropyl myristate, lactic acid, laurylamine, mesityl oxide, methoxy-propanol, methyl isoamyl ketone, methyl isobutyl ketone, methyl laurate, methyl octanoate, methyl oleate, methylene chloride, m-xylene, n-hexane, n-octylamine, octyl amine acetate, oleylamine, o-xylene, phenol, polyethylene glycol (PEG400), propionic acid, propylene glycol, propylene glycol monomethyl ether, propylene glycol mono-methyl ether, p-xylene, toluene, triethyl phosphate, triethylene glycol, xylene sulfonic acid, trichloroethylene, perchloroethylene, ethyl acetate, amyl acetate, butyl acetate, propylene glycol monomethyl ether and diethylene glycol monomethyl ether, methanol, ethanol, isopropanol, and higher molecular weight alcohols such as amyl alcohol, tetrahydrofurfuryl alcohol, hexanol, octanol, etc., ethylene glycol, propylene glycol, glycerine, N-methyl-2-pyrrolidinone, and the like. Water is generally the carrier of choice for the dilution of concentrates.

A broad range of surface-active agents can be employed in both solid and liquid compositions, especially those designed to be diluted with carrier before application. Suitable surface-active compounds are nonionic, cationic and/or anionic surfactants and surfactant mixtures having good emulsifying, dispersing and wetting properties. Examples of suitable surfactants and surfactant mixtures are given in U.S. Pat. Nos. 5,958,835; 6,063,732 and 6,165,939. Also the surfactants customarily used for the art of formulation and described, inter alia, in "McCutcheon's Detergents and Emulsifiers Annual" MC Publishing Corp., Ridgewood N.J., 1981, Stache, H., "Tensid-Taschenbuch" (Handbook of Surfactants), Carl Hanser Verlag, Munich/Vienna, 1981, and M. and J. Ash, "Encyclopedia of Surfactants", Vol I-III, Chemical Publishing Co., New York, 1980-81 are suitable for manufacture of the herbicides according to the invention.

Compounds that are Capable of Releasing H2S.

Any compound that can be coated onto a seed and that can release H2S after planting can be incorporated into the methods, seeds, and kits described herein.

Many different hydrogen sulfide donors have been developed. They release hydrogen sulfide by reaction with water, thiols, amines, or other functional groups or the release is triggered by an external stimulus such as light. Some representative compounds are shown in Figures la-le. These chemicals have different structural motifs. The compounds in Figure la possess carbon-sulfur double or single bonds. The compounds in Figure lb, possess phosphorous-sulfur double bonds. The compounds in Figure 1c possess carbon-sulfur single bonds and are monosulfides, disulfides, trisulfides, or potentially higher sulfides. The compounds in Figure Id possess sulfur-nitrogen or sulfur-oxygen bonds. The compounds in Figure le are either metal sulfides or sulfide salts with counterions such as sodium or other appropriate cations.

In one embodiment, the compound that is capable of releasing H2S possess a carbonsulfur double bond.

In one embodiment, the compound that is capable of releasing H2S possess a carbonsulfur single bond.

In one embodiment, the compound that is capable of releasing H2S possess a phosphorous-sulfur double bond.

In one embodiment, the compound that is capable of releasing H2S a monosulfide, a disulfide, a trisulfide, or a higher sulfide.

In one embodiment, the compound that is capable of releasing H2S possesses a sulfurnitrogen or a sulfur-oxygen bond

In one embodiment, the compound that is capable of releasing H2S is a metal sulfide or a sulfide salts with a counterion such as sodium, potassium or ammonium. In one embodiment, the compound that is capable of releasing H2S is not a compound of formula I; wherein:

Y is O or S;

Z is O or S;

R¹ is (Ci-C2o)alkyl, phenyl, or (C3-C2o)cycloalkyl; and R² is (Ci-C2o)alkyl, phenyl, or (C3-C2o)cycloalkyl; or R¹ and R² taken together with the atoms to which they are attached form a 5-15 membered heterocyclic ring that is optionally substituted with one or more groups independently selected from the group consisting of (Ci-Ce)alkyl, (C3-Ce)cycloalkyl, and phenyl, wherein any phenyl or cycloalkyl of R¹ and R² is optionally substituted with one or more groups independently selected from the group consisting of (Ci-Ce)alkyl, (C3-Ce)cycloalkyl, and phenyl; and

X⁺ is a suitable cation.

In one embodiment, the compound that is capable of releasing H2S is not selected from the group consisting of:

wherein X⁺ is a suitable cation.

In one embodiment, the compound that is capable of releasing H2S is not a trisulfide or a tetrasulfide.

In one embodiment, the compound that is capable of releasing H2S is not a compound of formula (II):

RAS-S-S-R² (II) or a salt thereof, wherein:

R¹ is (Ci-C2o)alkyl, (Ci-C2o)alkenyl, (Ci-C2o)alkynyl, phenyl, a residue of cysteine, a residue of methionine, a residue of N-acetyl cysteine, a residue of N-acetyl methionine, a residue of homocysteine, a residue of lipoic acid, a residue of coenzyme, a residue of glutathione, or a residue of any other other naturally occurring thiol; and

R² is (Ci-C2o)alkyl, (Ci-C2o)alkenyl, (Ci-C2o)alkynyl, phenyl, a residue of cysteine, a residue of methionine, a residue of N-acetyl cysteine, a residue of N-acetyl methionine, a residue of homocysteine, a residue of lipoic acid, a residue of coenzyme, a residue of glutathione, or a residue of any other other naturally occurring thiol.

In one embodiment, the compound that is capable of releasing H2S is cysteine trisulfide, methionine trisulfide, N-acetyl cysteine trisulfide, N-acetyl methionine trisulfide, or glutathione tri sulfide. In one embodiment, the compound that is capable of releasing H2S is N-acetyl cysteine tri sulfide.

In one embodiment, the compound that is capable of releasing H2S is a compound of formula (III):

R³-S-S-S-S-R⁴ (III) or a salt thereof, wherein:

R³ is (Ci-C2o)alkyl, (Ci-C2o)alkenyl, (Ci-C2o)alkynyl, phenyl, a residue of cysteine, a residue of methionine, a residue of N-acetyl cysteine, a residue of N-acetyl methionine, a residue of homocysteine, a residue of lipoic acid, a residue of coenzyme, a residue of glutathione, or a residue of any other other naturally occurring thiol; and

R⁴ is (Ci-C2o)alkyl, (Ci-C2o)alkenyl, (Ci-C2o)alkynyl, phenyl, a residue of cysteine, a residue of methionine, a residue of N-acetyl cysteine, a residue of N-acetyl methionine, a residue of homocysteine, a residue of lipoic acid, a residue of coenzyme, a residue of glutathione, or a residue of any other other naturally occurring thiol.

In one embodiment, the compound that is capable of releasing H2S is cysteine tetrasulfide, methionine tetrasulfide, N-acetyl cysteine tetrasulfide, glutathione tetrasulfide, or N-acetyl methionine tetrasulfide.

In one embodiment, the compound that is capable of releasing H2S is N-acetyl cysteine tetrasulfide.

Coated Seeds

As used herein, the term “a seed having a coating that comprises a compound that is capable of releasing H2S after the seed is planted,” means a seed that has the compound on a surface of the seed. In one embodiment, the coating comprises the compound. In one embodiment, the coating consists essentially of the compound. In one embodiment, the coating completely covers the seed. In one embodiment, the coating covers less than 2% of the seed. In one embodiment, the coating covers less than 5% of the seed. In one embodiment, the coating covers less than 10% of the seed. In one embodiment, the coating covers less than 20% of the seed. In one embodiment, the coating covers at least 1% of the seed. In one embodiment, the coating covers at least 2% of the seed. In one embodiment, the coating covers at least 5% of the seed. In one embodiment, the coating covers at least 10% of the seed. In one embodiment, the coating covers at least 20% of the seed. In one embodiment, the coating covers at least 50% of the seed. In one embodiment, the coating covers at least 75% of the seed. In one embodiment, the coating covers at least 90% of the seed. In one embodiment, the coating covers at least 95% of the seed. In one embodiment, the coating covers at least 99% of the seed.

In one embodiment, the coating covers l%-5% of the seed. In one embodiment, the coating covers 1%-10% of the seed. In one embodiment, the coating covers l%-20% of the seed. In one embodiment, the coating covers 10%-20% of the seed. In one embodiment, the coating covers 20%-30% of the seed. In one embodiment, the coating covers 30%-40% of the seed. In one embodiment, the coating covers 40%-50% of the seed. In one embodiment, the coating covers 50%-60% of the seed. In one embodiment, the coating covers 60%-70% of the seed. In one embodiment, the coating covers 70%-80% of the seed. In one embodiment, the coating covers 80%-90% of the seed. In one embodiment, the coating covers 90%-100% of the seed.

Fig. 2 shows an illustration of a cross-sectional view of a coated seed 1500 including a seed 1502 and a coating 1504. Fig. 3 shows an illustration of a perspective view of a coated seed 1600 in which the seed 1502 (defined by the hidden line 1602) is completely covered by the coating 1504. Fig. 4 shows an illustration of a perspective view of a coated seed 1700 in which the seed 1502 (defined by the hidden line 1602) is partially covered by the coating 1504.

Coating a seed with a compound prior to planting the seed reduces the amount of the compound needed to increase growth or harvest yield in a plant that grows from the seed compared to the amount of the compound that needed to produce the same increase in growth or harvest yield if the compound is applied to a field after planting the seed. This provides a significant savings in cost. In one embodiment, the coating comprises 0.5 mg of the compound or less. In another embodiment, the coating comprises 0.4 mg of the compound or less. In another embodiment, the coating comprises 0.3 mg of the compound or less. In another embodiment, the coating comprises 0.2 mg of the compound or less. In another embodiment, the coating comprises 0.1 mg of the compound or less. In another embodiment, the coating comprises 0.05 mg of the compound or less. In another embodiment, the coating comprises 0.03 mg of the compound or less. In another embodiment, the coating consists essentially of 0.5 mg of the compound or less. In another embodiment, the coating consists essentially of 0.4 mg of the compound or less. In another embodiment, the coating consists essentially of 0.3 mg of the compound or less. In another embodiment, the coating consists essentially of

0.2 mg of the compound or less. In another embodiment, the coating consists essentially of

0.1 mg of the compound or less. In another embodiment, the coating consists essentially of

0.05 mg of the compound or less. In another embodiment, the coating consists essentially of 0.03 mg of the compound or less. In another embodiment, the coating consists essentially of

0.01 mg of the compound or less.

Kits

In one embodiment, a kit comprising one or more coated seeds and packaging material containing the one or more coated seeds is provided. The packaging material can be any material that is suitable for storing or transporting the coated seeds. For example, the packaging material can be an envelope, e.g., a seed envelope, that is suitable for display in a retail setting; the envelope may include illustrations of the seeds or the corresponding plants. The packaging material can also be a bag or other container that can be used for the storage, sale, or transportation of a bulk quantity (e.g., kilograms) of the coated seeds. For example, the packaging material may comprise plastic or paper.

Methods

In one embodiment, a method comprising, increasing growth or increasing harvest yield in a plant that grows from a seed by coating the seed with a compound capable of releasing H2S is provided. In one embodiment, the coating comprises 0.5 mg of the compound or less. In another embodiment, the coating comprises 0.4 mg of the compound or less. In another embodiment, the coating comprises 0.3 mg of the compound or less. In another embodiment, the coating comprises 0.2 mg of the compound or less. In another embodiment, the coating comprises 0.1 mg of the compound or less. In another embodiment, the coating comprises 0.05 mg of the compound or less. In another embodiment, the coating comprises 0.03 mg of the compound or less, In another embodiment, the coating consists essentially of 0.5 mg of the compound or less, In another embodiment, the coating consists essentially of 0.4 mg of the compound or less, In another embodiment, the coating consists essentially of 0.3 mg of the compound or less, In another embodiment, the coating consists essentially of 0.2 mg of the compound or less. In another embodiment, the coating consists essentially of 0.1 mg of the compound or less. In another embodiment, the coating consists essentially of 0.05 mg of the compound or less. In another embodiment, the coating consists essentially of 0.03 mg of the compound of or less.

Coating Methods

Seed coatings can be applied to seeds in several ways. In one non-limiting method, a compound is dissolved or suspended in a solvent such as water, the resulting liquid is applied to seeds, and the solvent is evaporated. In another non-limiting method, a compound is applied as a seed treatments in a planter box. In this method, chemicals are either alone or in mixtures as solids. The solids are placed on top of seeds and then the solids are allowed to flow through the seeds and coat them. In a third non-limiting method, a compound is applied either as a solid or a liquid to the seed at planting.

In one embodiment, a method comprising combining a seed and a compound under conditions that provide a seed coated with the compound is provided. In one embodiment, the coating consists essentially of the compound. In one embodiment, the coating completely covers the seed. In one embodiment, the coating covers at least 50% of the seed. In one embodiment, the coating covers at least 75% of the seed. In one embodiment, the coating covers at least 90% of the seed. In one embodiment, the coating at least 95% of the seed. In one embodiment, the coating covers at least 99% of the seed. In one embodiment, the coating comprises 0.5 mg of the compound or less. In one embodiment, the coating comprises 0.4 mg of the compound or less. In one embodiment, the coating comprises 0.3 mg of the compound or less. In one embodiment, the coating comprises 0.2 mg of the compound or less. In one embodiment, the coating comprises 0.1 mg of the compound or less. In another embodiment, the coating comprises 0.05 mg of the compound or less. In another embodiment, the coating comprises 0.03 mg of the compound or less. In one embodiment, the coating consists essentially of 0.5 mg of the compound or less. In one embodiment, the coating consists essentially of 0.4 mg of the compound or less. In one embodiment, the coating consists essentially of 0.3 mg of the compound or less. In one embodiment, the coating consists essentially of 0.2 mg of the compound or less. In one embodiment, the coating consists essentially of 0.1 mg of the compound or less. In another embodiment, the coating consists essentially of 0.05 mg of the compound or less. In another embodiment, the coating consists essentially of 0.03 mg of the compound or less.

In one embodiment, the method comprises combining the seed, the compound and a surfactant under conditions that provide an unplanted seed coated with the compound. Suitable surfactants include nonionic, cationic and/or anionic surfactants and surfactant mixtures having good emulsifying, dispersing and wetting properties. Examples of suitable surfactants and surfactant mixtures are given in U.S. Pat. Nos. 5,958,835; 6,063,732 and 6,165,939. Also the surfactants customarily used for the art of formulation and described, inter alia, in "McCutcheon's Detergents and Emulsifiers Annual" MC Publishing Corp., Ridgewood N.J., 1981, Stache, H., "Tensid-Taschenbuch" (Handbook of Surfactants), Carl Hanser Verlag, Munich/Vienna, 1981, and M. and J. Ash, "Encyclopedia of Surfactants", Vol I-III, Chemical Publishing Co., New York, 1980-81 are suitable for manufacture of the herbicides according to the invention. In one embodiment, the surfactant is a non-ionic surfactant. In one embodiment, the surfactant is SPRET ® (Surfactant).

In one embodiment, the method comprises combining the seed, the compound and a pesticide under conditions that provide a seed coated with the compound. Suitable pesticides include Obvius Plus Specimen fungicide seed treatment (BASF Corporation), Dyna-Shield imidacloprid 5 (Loveland Products), and Cruiser Maxx Vibrance Cereals (Syngenta).

In one embodiment, the method comprises combining the seed, the compound and a fungaside under conditions that provide a seed coated with the compound. Suitable fungasides include: Delaro ( Bayer), Poncho Votivo (BASF), Luna (Bayer), and Maxim 4FS.

Lubricants (e.g., talc or graphite) are often to lubricate seeds as they are being planted. Seeds interacting with planters have friction, so not all seeds are planted when intended. For instance, out of 1,000 opportunities to plant a seed, a seed might be successfully planted only 95% of the time. The other 5% of the time two seeds may be planted at once or no seed may be planted. Lubricants can increase the success rate for planting one seed when intended. Lubricants are often used with other chemicals to add additional benefits to plants (see https://ylsci.com/products/seed-graphite/#:~:text=SEED%2BGRAPHITE%20is%20a%20 nutritional, stressors%2C%201eading%20to%20higher%20yields.). In one embodiment, the method comprises combining the seed, the compound and a lubricant under conditions that provide a seed coated with the compound and the lubricant. Seeds can also be coated with other chemicals such as micronutrients, fungicides, pesticides, dyes, or a stabilizer to keep all in place. Nearly all commercial corn is coated with multiple products before sale. In one embodiment, the seed is coated with a compound capable of releasing H2S and one or more agents selected from the group consisting of micronutrients, fungicides, pesticides, lubricants, dyes, and stabilizers. In one embodiment, the method comprises combining the seed, the compound and one or more agents selected from the group consisting of micronutrients, fungicides, pesticides, lubricants, dyes, pesticides, fungasides and stabilizers under conditions that provide a seed coated with the compound and one or more agents selected from the group consisting of micronutrients, fungicides, pesticides, lubricants, dyes, pesticides, fungasides and stabilizers.

In one embodiment, the method further comprises drying the coated seed.

Plants

As used herein, the term “plant that grows from a seed” includes any plant that grows from a seed. In one embodiment, the plant that grows from a seed is a beneficial plant. In one embodiment, the plant that grows from a seed is a root vegetable, a seed vegetable, or a leaf vegetable. In one embodiment, the plant that grows from a seed is a fruit, vegetable, hay, alfalfa, an oil seed plant, or miscanthus. In one embodiment, the plant that grows from a seed is a pea, lettuce, tomato, cucumber, green bean, broccoli, squash, beat, onion, sugar, com (field or sweet), sugar beet, barley, oat, wheat, potato, or radish. In one embodiment, the plant that grows from a seed is corn (field or sweet) or wheat. In one embodiment, the plant that grows from a seed is wheat.

As used herein, the term “seed” includes any entity that, once placed into soil or another suitable growing medium, will grow into a plant. For example, the term includes seeds, kernels, tubers, bulbs, corms, and achenes.

The invention will now be illustrated by the following Examples. EXAMPLES

Example 1. Spray Coating

Dibutyldithiophosphate potassium salt was applied as a seed coating onto corn and soybean seeds. The dibutyldithiophosphate potassium salt was dissolved in water at approximately 50% by weight, and it was sprayed onto corn seeds that already had a seed coating. The amount of dibutyldithiophosphate potassium salt that was sprayed yielded on average 0.1 mg of the salt on each seed. Soybean seeds were similarly coated with on average 0.1 mg of the salt on each seed by spraying the aqueous solution on them and allowing the water to evaporate. The seeds were stored until planting.

The seeds were planted into fields and fertilized as needed. Control plots were planted where the corn and soybean seeds were not coated with dibutyldithiophosphate potassium salt. The corn plants were harvested and the harvest yields of the plants that were originally exposed to dibutyldithiophosphate potassium salt yielded an average harvest yield of 253.8 bushels per acre compared to the yield of the control plants that were not exposed to the salt and had a yield of 239.6 bushels per acre. The soybean plants were harvested and the harvest yields of plants that were originally exposed to dibutyldithophosphate potassium salt yielded an average of 58.8 bushels/acre compared to the yield of the control plants that were not exposed to the salt and had a yield of 56.8 bushels per acre.

Example 2. Planter Box Application

Dibutyldithiophosphate salt was applied as a planter box treatment. An aqueous solution of dibutyldithiophosphate salt was dried to yield an off-white solid. This solid was ground up and sieved through a 80 mesh filter. The solid that passed through the filter was then mixed with a seed lubricant on a 50% by weight basis. The mixture was applied as a planter box treatment by addition to the top of seeds prior to planting. The amount of dibutyl di thiophosphate was on average 0.1 mg per seed.

Corn and soybean seeds were planted using the planter box treatment with the dibutyldithiophosphate potassium salt and fields were also planted with a planter box treatment that did not contain the dibutyldithiophosphate potassium salt as control fields. The harvest yield of soybean plants planted using dibutyldithiophosphate potassium salt was 68.2 bushels per acre and the yield of the control plants not exposed to the salt was 67.4 bushels per acre. The harvest yield of corn plants planted using dibutyldithiophosphate potassium salt was 243.4 bushels per acre and the yield of the control plants not exposed to the salt was 240.9 bushels per acre. All publications, patents, and patent documents are incorporated by reference herein, as though individually incorporated by reference. The invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention.

Claims

CLAIMS What is claimed is:

1. A method for increasing growth or harvest yield of a plant that grows from a seed comprising coating the seed with a compound capable of releasing H2S to provide a seed having a coating that comprises the compound that is capable of releasing H2S.

2. The method of claim 1, wherein the seed is coated with the compound prior to planting.

3. The method of claim 1, wherein the seed is coated with the compound after planting.

4. The method of any one of claims 1-3, wherein with a coating consists essentially of the compound.

5. The method of any one of claims 1-3, wherein the coating completely covers the seed.

6. The method of any one of claims 1-3, wherein the coating covers less than 2% of the seed.

7. The method of any one of claims 1-3, wherein the coating covers less than 5% of the seed.

8. The method of any one of claims 1-3, wherein the coating covers at least 50% of the seed.

9. The method of any one of claims 1-3, wherein the coating covers at least 75% of the seed.

10. The method of any one of claims 1-3, wherein the coating covers at least 99% of the seed.

11. The method of any one of claims 1-3, wherein the coating comprises 0.5 mg of the compound or less.

12. The method of any one of claims 1-3, wherein the coating comprises 0.4 mg of the compound or less.

13. The method of any one of claims 1-3, wherein the coating comprises 0.3 mg of the compound or less.

14. The method of any one of claims 1-3, wherein the coating comprises 0.2 mg of the compound or less.

15. The method of any one of claims 1-3, wherein the coating comprises 0.1 mg of the compound or less.

16. The method of any one of claims 1-3, wherein the coating consists essentially of 0.5 mg of the compound or less.

17. The method of any one of claims 1-3, wherein the coating consists essentially of 0.4 mg of the compound or less.

18. The method of any one of claims 1-3, wherein the coating consists essentially of 0.3 mg of the compound or less.

19. The method of any one of claims 1-3, wherein the coating consists essentially of 0.2 mg of the compound or less.

20. The method of any one of claims 1-3, wherein the coating consists essentially of 0.1 mg of the compound or less.

21. The method of any one of claims 1-20, wherein the compound is not a compound of formula (I); wherein:

Y is O or S;

Z is O or S;

X⁺ is a suitable cation.

22. The method of any one of claims 1-21, wherein the compound is not a compound of formula (II):

RkS-S-S-R² (II) or a salt thereof, wherein:

R¹ is Ci-C2o)alkyl, (Ci-C2o)alkenyl, (Ci-C2o)alkynyl, phenyl, a residue of cysteine, a residue of methionine, a residue of N-acetyl cysteine, a residue of N-acetyl methionine, a residue of homocysteine, a residue of lipoic acid, a residue of coenzyme, a residue of glutathione, or a residue of any other other naturally occurring thiol; and

R² is Ci-C2o)alkyl, (Ci-C2o)alkenyl, (Ci-C2o)alkynyl, phenyl, a residue of cysteine, a residue of methionine, a residue of N-acetyl cysteine, a residue of N-acetyl methionine, a residue of homocysteine, a residue of lipoic acid, a residue of coenzyme, a residue of glutathione, or a residue of any other other naturally occurring thiol.

23. A seed having a coating that comprises a compound that is capable of releasing H2S after the seed is planted.

24. The seed of claim 23, wherein the coating comprises the compound.

25. The seed of claim 23, wherein the coating consists essentially of the compound.

26. The seed of any one of claims 23-25, wherein the coating completely covers the seed.

27. The seed of any one of claims 23-25, wherein the coating covers at least 50% of the seed.

28. The seed of any one of claims 23-25, wherein the coating covers at least 75% of the seed.

29. The seed of any one of claims 23-25, wherein the coating covers at least 90% of the seed.

30. The seed of any one of claims 23-25, wherein the coating covers at least 95% of the seed.

31. The seed of any one of claims 23-25, wherein the coating covers at least 99% of the seed.

32. The seed of any one of claims 23-25, wherein the coating comprises 0.5 mg of the compound or less.

33. The seed of any one of claims 23-25, wherein the coating comprises 0.4 mg of the compound or less.

34. The seed of any one of claims 23-25, wherein the coating comprises 0.3 mg of the compound or less.

35. The seed of any one of claims 23-25, wherein wherein the coating comprises 0.2 mg of the compound or less.

36. The seed of any one of claims 23-25, wherein the coating comprises 0.1 mg of the compound or less.

37. The seed of any one of claims 23-25, wherein the coating consists essentially of 0.5 mg of the compound or less.

38. The seed of any one of claims 23-25, wherein the coating consists essentially of 0.4 mg of the compound or less.

39. The seed of any one of claims 23-25, wherein the coating consists essentially of 0.3 mg of the compound or less.

40. The seed of any one of claims 23-25, wherein the coating consists essentially of 0.2 mg of the compound or less.

41. The seed of any one of claims 23-25, wherein the coating consists essentially of 0.1 mg of the compound or less.

42. The seed of any one of claims 23-41, wherein the compound is not a compound of formula (I); wherein:

Y is O or S;

Z is O or S;

X⁺ is a suitable cation.

43. The seed of any one of claims 23-42, wherein the compound is not a compound of formula (II):

RkS-S-S-R² (II) or a salt thereof, wherein:

44. The seed of any one of claims 23-36 and 42-43, wherein the coating further comprises one or more agents selected from the group consisting of micronutrients, fungicides, pesticides, lubricants, dyes, pesticides, fungasides and stabilizers.

45. A method comprising combining a seed, a compound capable of releasing H2S after planting, and one or more agents selected from the group consisting of micronutrients, fungicides, pesticides, lubricants, dyes, pesticides, fungasides and stabilizers under conditions that provide a seed coated with the compound capable of releasing H2S and one or more of the agents.

46. A coated seed prepared as described in claim 45.

47. A kit comprising; one or more seeds having a coating as described in any one of claims 23-44; and packaging material containing the one or more seeds.

48. The kit of claim 47, wherein the packaging material is an envelope.

49. The kit of claim 47, wherein the packaging material is a bag.

50. The kit of claim 47, wherein the packaging material is a bag that comprises plastic or paper.

51. The kit of any one of claims 47-50, which further comprises instructions for planting the one or more seeds having a coating.

52. The method of any one of claims 1-22 and 45 or the seed of any one of claims 23-44, wherein the plant is a root vegetable, a seed vegetable, or a leaf vegetable.

53. The method of any one of claims 1-22 and 45 or the seed of any one of claims 23-44, wherein the plant is a fruit, vegetable, hay, alfalfa, an oil seed plant, or miscanthus.

54. The method of any one of claims 1-22 and 45 or the seed of any one of claims 23-44, wherein the plant is a pea, lettuce, tomato, cucumber, green bean, broccoli, squash, beat, onion, sugar, sweet corn, sugar beet, barley, oats, wheet, potato, or radish.

55. The method of any one of claims 1-22 and 45 or the seed of any one of claims 23-44, wherein the plant is a corn or soybean.

56. The method of any one of claims 1-22 and 45 or the seed of any one of claims 23-44, wherein the compound is capable of releasing H2S over a period of at least about 2 days after the seed is planted.

57. The method of any one of claims 1-22 and 45 or the seed of any one of claims 23-44, wherein the compound is capable of releasing H2S over a period of at least about 7 days after the seed is planted.

58. The method of any one of claims 1-22 and 45 or the seed of any one of claims 23-44, wherein the compound is capable of releasing H2S over a period of at least about 1 year after the seed is planted.

59. A composition comprising a compound that is capable of releasing H2S and a surfactant, wherein the composition can be used to prepare a seed as described in any one of claims 23-44.

60. An invention as described herein.