First Report
Chemical Hybridizing Agents Identification of Chemical Hybridization Agents (CHA) suitable for commercial hybrid seed production in specific vegetable crops (enlisted as priority crops in the PC-I) along with mode of application.
Research By
Muhammad Boota Sarwar
For
Ministry of Food and Agriculture
Facilitation Unit for Participatory Vegetable Seed & Nursery Production Program Contents Sr. No. 1 Introduction
Title
Page No. 3
2
Types of Chemical Hybridization Agents
7
3
Categories of Potential Chemical Hybridization Agents
8
4
Classification of Herbicides
11
5
Some Gametocides
17
6
Plant Growth Regulators
25
7
Priority Crops for CHA Studies
33
8
Work Plan for the Months of February-March, 2010
34
2
INTRODUCTION Plant breeders have long been attempting to increase productivity of the more important crops used for food, or for processing as feed, fiber and pharmaceuticals, by their efforts in developing cultivars (cultivated varieties) with particularly desirable characteristics. One of the ways in which this aim is frequently accomplished is the development of superior plant lines by infusing desirable traits with already existing cultivars, thus potentially forming a hybrid with exceptional characteristics. The general superiority of F1 hybrids over either of their parents (hybrid vigor) is a widespread phenomenon in a variety of different types of crops. This superiority may express itself in such features as increased height, growth rate, leaf area, early flowering and overall higher yields. One way in which the production of superior plant lines has been achieved in the past is by the making of numerous manual cross pollinations to obtain the desired F1 hybrid. These crosses generally are carried out between an already existing cultivated crop variety and an un-adapted or "wild type" gene donor which possesses one or more traits which the breeder wishes to incorporate into the cultivated variety. Once the production of the F1 has been accomplished, repeated back-crossings and selections are then required to ultimately obtain a plant containing all the characteristics of the cultivated plant as well as retaining the new, desirable traits introduced from the "wild type" plants. As can easily be seen, this selection procedure is extremely tedious and time consuming; yet, in spite of the difficulties, it remains one of the most widespread of plant breeding techniques currently in use. Because of the problems involved with this method, a number of other avenues for more efficient production of F1 hybrids have been and are being explored. Among the most avidly pursued fields of endeavor is the construction of male sterile lines within the varieties of crop plants to which hybridization is desired. The principle behind the development of male sterile lines is that, in order to produce hybrid seed more economically, the restrictions of controlled cross3
fertilization imposed by floral morphology, especially of perfect flowers, must be overcome. To this end, the female parent should be prevented from self- or intraline fertilization. The elimination of selffertilization requires andro-self sterility, or the inability of the plant to produce viable pollen. The establishment of the male sterile line thus renders any crop variety readily adaptable to hybridization with virtually any gene donor having the desired characteristics, and eliminates the need for laborious hand pollination. Male sterile lines may be established in a number of ways. Hand emasculation is one method by which a line may be sterilized. For example, large scale production of hybrid corn may be done by detasselling the female parent; however, the large scale emasculation of species having perfect flowers generally proves to be economically unfeasible. Genetic male sterility is also a known trait, usually inherited as a recessive and monogenic trait in a number of different types of plants. Exploitation of this characteristic is used to produce hybrid seed of barley, tomato, pepper, marigold, zinnia, and others. However, there is a basic shortcoming in the use of this technique, in that it is difficult to obtain a 100% genetic male sterile stand. Overcoming this difficulty requires a rather complex use of clever genetic manipulation. Its use therefore is currently restricted to hybrid seed production of cultivated plants in which cytoplasmic male sterility has not been found, or that in which the male sterile plasma-type exhibits inferior agronomic performance. Cytoplasmic male sterility provides an additional mechanism for providing the desired lines for use in hybridization. In this situation, the genetic factors controlling male sterility are found in the cytoplasm. This trait is probably associated with some alteration of the normal structure or function of mitochondria of plastids. Cytoplasmic male sterility has found widespread application in the production of hybrid seed. Widespread production based on this trait is responsible for larger percentages of many important cultivated crops such as sorghum, sugar-beet, onions, melon, and, most successfully, corn. A number of difficulties exist with this system as well. First, it is difficult to ensure the expression of cytoplasmic male sterility across the range of environments in which hybrid seed may 4
be produced. A female wheat plant which is 100% sterile in one locality may prove to be only 50% sterile in another locality, thus producing obvious difficulties in hybrid seed production. Furthermore, once the sterile line is established, the female line must be maintained through the use of a male fertile maintainer line; and hybrid seed must be restored to at least semi-sterility via a "restorer" line. Clearly the necessary development of effective and appropriate maintainer and restorer lines presents a considerable obstacle to the efficient and economical exploitation of the trait for the production of hybrid seed. In fact, a number of important cereal crops, such as wheat, have continued to resist all efforts to establish efficient cytoplasmic male sterility restorer lines. A method of producing male sterile lines which circumvents the difficulties of genetic induction is the use of chemical sterilization agents. The principle involved here is that the chemical acts as a gametocide selectively altering the male gamete, i.e., pollen, by inducing physiological abnormalities, which in turn prevent pollen development, pollen shed, or pollen viability. A number of chemical compounds have been shown to have at least a partial effect in producing male sterility in plants. Among these are: 2chloroethylphosphonic acid (ethephon; Berhe et al., Crop Science 18: 35-38, 1978); sodium 1-(p-chlorophenyl)-1,2-dihydro-4,6-dimethyl-2oxonicotinate (RH-531 532; Jan et al., Euphytica 23: 78-85, 1974); 3(p-chlorophenyl)-6-methoxy-s-triazine-2,4 (1H,3H) dionetriethanolamine (DPX3778; Johnson et al., Crop Science 18: 10261028; 2,7-diamino-10-ethyl-6-phenylantridium bromide (ethidium bromide; Burton et al., Crop Science 16: 731-2, 1976). Although use of these compounds obviates the problems encountered with genetic manipulation, there are still a number of difficulties which might arise with use of chemical sterilants. For example, chemical treatment may result in induction of only partial sterility, or may be variable in the degree of male sterility induced under field conditions. They also may produce phytotoxic side effects, such as seed shrinking, which may reduce the viability and/or agricultural utility. Further, female sterility may also be induced by the use of some of these chemicals. Another undesirable feature is that for the most part, these compounds are applied as foliar sprays. The 5
necessity of such application presents the problem of environmental pollution, and synchrony with the exact plant stage of development. It has now been discovered that another class of compounds, DABCO (1,4-Diazabicyclo[2.2.2]octane) and its quaternary salt derivatives have the unexpected effect of causing male sterility in plants. The subject compounds, which are preferably used to treat seeds directly, are thus not limited to use as foliar chemisterilant sprays, although this is an alternate method of application. Use of these compounds for chemical emasculation allows for the development of all female plants which may be used to produce large quantities of hybrid seed. These compounds have the added advantage of producing male sterility in wheat, a plant which has traditionally resisted all attempts to establish a successful hybrid seed production program. The sex expression in monoecious plants like cucurbits and hemp largely depend on balance of auxins; and application of Cytokinin or Gibberellin may change the vegetative and reproductive phases as well as the frequency of male and female flowers. This technique is widely used for hybrid seed production. There are other chemical hybridization agents which are used in the background of genetically modified female lines. Such male sterile lines can be easily converted to male fertile lines by the application of certain chemicals. Present study envisages reviewing broad array of available chemical hybridization agents to identify commercially viable chemicals along with practical standardization of modus operundi for hybrid seed production of vegetable crops.
6
Types of Chemical Hybridization Agents Various types of natural or synthetic chemicals and physical agents are used for affecting reproductive system of plants to facilitate hybrid seed production. The chemicals when applied on plants on specific time and in specific dose act in diverse ways as detailed below: 1. Some chemicals suppress production or functioning of male
gametes in bisexual (hermaphrodite) flowers. 2. Some chemicals influence frequency of male or female flowers
in monoecious plants having separate male and female flowers on same plant and thus the subject plants temporarily become predominantly male or female, as the case may be. 3. Some chemicals regulate growth of plants or change of
vegetative to reproductive phase for the purpose of synchronizing the flowering period in male and female parent lines. In many crops synchronizing of flowering period in male and female lines is main problem in improving yield of hybrid seed. 4. Spray of some chemicals affects exertion of stigma in bisexual
flowers to avoid self-pollination and favor crossing. 5. Some chemicals are used to convert male-sterile plants into
male-fertile normal plants in conditionally male-sterile plants. Such chemicals remove deficiency of specific micronutrient, enzyme or hormone and plant starts behaving normally. The conditionally male-sterile plants are developed through genetic modification. 6. Some chemicals are used to trigger function of certain genes
for conversion of normal plants to male-sterile plants and vice versa in the background of genetic modifications to produce such plants.
7
Categories of Potential Chemical Hybridization Agents Diverse categories of natural and synthetic chemicals can affect reproductive system of plants and thus have potential for using as Chemical Hybridization Agents (CHA). Main categories of such chemicals are as under: Auxins: 1. Gibberellic acid (GA3), 2. (GA4/7),
3. 4. 5. 6. 7. 8.
Ethephon, DPX-3718, Cytokinin, Naphthalene Acetic Acid (NAA), Ethylene Abscisic acid (AA)
Anti-auxins: 1. 2. 3. 4.
NM, TIBA, 2, 4–D, MH
Physical Agents: 1. 2. 3. 4. 5.
Carbon Dioxide Electrical current Abiotic stresses Nitrogen regulation Photoperiods
Herbicides: 1. 2,4-dichlorophenoxyacetic acid 2. Glyphosate (fely): [isopropylamine salt of N(phosphonomethyl)glycine] 3. Alachlor: [2-chloro-2'-6'- diethyl-N-(methoxymethyl)acetanilide) 8
4. Glufosinate: [2-amino-4-(hydroxymethylphosphinyl)butanoic acid] 5. Diphenylpyridazinones 6. EMBUTOX: 2, 4-Dichlorophenoxybutyric acid Defoliants and Desiccants: 1. Agent orange 2. Carfentrazone (Aim) 3. Dimethipin (Harvade, Leafless, Lintplus) 4. Diquat (Reglone, Diquash) 5. Endothall (Accelerate, Desicate-II) 6. Paraquat (Gramoxone) 7. Pelargonic acid (Scythe) 8. Pyraflufen ethyl (ET) 9. Sodium chlorate (Defol) 10. Thiadiazuron (Daze, Dropp, FreeFall, Ginstar, Klean-Pik, Leafless, Redi-Pik, Take Down, TDZ) 11. Tribufos (Def, Folex) Enzymes and Hormones: 1. 2. 3. 4. 5. 6.
Male enzyme andrase Female enzyme gynase GABA: γ-Aminobutyric acid Female hormones: Estrogens Female hormones: Progesterone Synthetic steroids: estrogen (oestrogen) and a progestin (progestogen).
Gametocides: 1. 2. 3. 4. 5. 6. 7. 8. 9.
RH-531, RH-532, RH-2956, RH-4667, RH-5148, RH-0007 (HYBREX), Shell’s CHA, WL-84811, Clofencet (Genesis) 9
10. LY-195259 11. FW-450 or Mendok (sodium 2,3-dichloroiso-butyrate or sodium 2,3-dichloro-2-methylpropionic acid), 12. Sodium dichloroacetate, 13. Dalapon (2,2-dichloropropionic acid) 14. Pyrazoles 15. Maleic hydrazide (MH) = (1,2-dihydropyridiazine 3,6dione)
16. 17.
Tri-iodobenzoic acid Aesculus parviflora: 3-azabicyclo(3.1.0)hexane-2-
carboxylic acid
18. Nitroarylalkylsulfone derivatives 19. Terpenoid compounds of the methylcyclohexene series 20. Hydroxyalkylesters of N-phosphonomethylglycine 21. Pyridazinylcarboxylic acid and its derivative 22. 3-Carboxyazetidine or a hydrate, salt or lower alkyl ester thereof 23. Diphenylpyridazinones 24. 5-oxy-substituted cinnoline 25. Ethyl oxanilates 26. Ethrelat 27. Denzotriazole 28. Pyridones 29. Ethyl oxanilates 30. Ethyl 4'fluorooxanilate 31. Cinnoline 32. 3-Substituted-2-carboxyazetidines 33. Tri-iodobenzoic acid 34. Other Chemicals: 1. Carbamate 2. Acetylene, produced through combination of calcium carbide with water. 3. Bethylene 4. Silver nitrate 5. Cobalt chloride 6. Detergents 10
Classification of Herbicides Herbicides including weedicides are generally used to kill the plants through various modes of action but it has been observed that such chemicals have good potential for use as chemical hybridizing agents. Therefore before selecting appropriate chemical for specific crop it is useful to understand classification of the herbicides. Main groups of herbicides are detailed below: 1. Amide Herbicides: allidochlor, amicarbazone, beflubutamid, benzadox, benzipram, bromobutide, cafenstrole, CDEA, cyprazole, dimethenamid dimethenamid-P, diphenamid, epronaz, etnipromid, fentrazamide, flucarbazone, flupoxam, fomesafen, halosafen, isocarbamid, isoxaben, napropamide, naptalam, pethoxamid, propyzamide, quinonamid, saflufenacil, tebutam
2. Anilide Herbicides: chloranocryl, cisanilide, clomeprop, cypromid, diflufenican, etobenzanid, fenasulam, flufenacet, flufenican, ipfencarbazone, mefenacet, mefluidide, metamifop, monalide, naproanilide, pentanochlor, picolinafen, propanil, sulfentrazone
3. Arylalanine Herbicides: benzoylprop, flamprop and flamprop-M 4. Chloroacetanilide Herbicides: acetochlor, alachlor, butachlor, butenachlor, delachlor, diethatyl, dimethachlor, metazachlor, metolachlor, S-metolachlor, pretilachlor, propachlor, propisochlor, prynachlor, terbuchlor, thenylchlor, xylachlor
5. Sulfonanilide Herbicides: benzofluor, cloransulam, diclosulam, florasulam, flumetsulam, metosulam, perfluidone, pyrimisulfan, profluazol
6. Sulfonamide Herbicides: asulam, carbasulam, fenasulam, oryzalin, penoxsulam, pyroxsulam
7. Thioamide Herbicides: bencarbazone and chlorthiamid 8. Antibiotic Herbicides: bilanafos 9. Aromatic, benzoic acid herbicides: chloramben, dicamba, 2,3,6-TBA, tricamba
11
10.
Aromatic, pyrimidinyloxybenzoic acid herbicides:
bispyribac, pyriminobac
11.
Aromatic, pyrimidinylthiobenzoic acid herbicides:
pyrithiobac
12.
Aromatic, phthalic acid herbicides: chlorthal
13.
Aromatic, picolinic acid herbicides: aminopyralid, clopyralid,
picloram
14.
Aromatic, quinolinecarboxylic acid herbicides: quinclorac
and quinmerac
15.
Arsenical Herbicides: cacodylic acid, CMA, DSMA, hexaflurate,
MAA, MAMA, MSMA, potassium arsenite, sodium arsenite
16.
Benzoylcyclohexanedione Herbicides: ketospiradox,
mesotrione, sulcotrione, tefuryltrione, tembotrione
17.
Benzofuranyl alkylsulfonate herbicides: benfuresate and
ethofumesate
18.
benzothiazole herbicides: benazolin, benzthiazuron, fenthiaprop, mefenacet, methabenzthiazuron
19.
Carbamate Herbicides: asulam, carboxazole, chlorprocarb,
dichlormate, fenasulam, karbutilate, terbucarb
20.
Carbanilate Herbicides: barban, BCPC, carbasulam, carbetamide, CEPC, chlorbufam, chlorpropham, CPPC, desmedipham phenisopham, phenmedipham, phenmedipham-ethyl, propham, swep
21.
Cyclohexene oxime Herbicides: alloxydim, butroxydim, clethodim, cloproxydim, cycloxydim, profoxydim, sethoxydim, tepraloxydim, tralkoxydim
22.
Cyclopropylisoxazole Herbicides: isoxachlortole and
isoxaflutole
23.
Dicarboximide herbicides: cinidon-ethyl, flumezin, flumiclorac,
flumioxazin, flumipropyn
12
24.
Dinitroaniline herbicides: benfluralin, butralin, dinitramine, ethalfluralin, fluchloralin, isopropalin, methalpropalin, nitralin, oryzalin, pendimethalin, prodiamine, profluralin, trifluralin
25.
Dinitrophenol herbicides: dinofenate, dinoprop, dinosam,
dinoseb, dinoterb, DNOC, etinofen, medinoterb
26.
Diphenyl ether herbicides: ethoxyfen
27.
Nitrophenyl ether herbicides: acifluorfen, aclonifen, bifenox, chlomethoxyfen, chlornitrofen, etnipromid, fluorodifen, fluoroglycofen, fluoronitrofen, fomesafen, furyloxyfen, halosafen, lactofen, nitrofen, nitrofluorfen, oxyfluorfen
28.
Dithiocarbamate herbicides: dazomet, metam
29.
Halogenated aliphatic herbicides: alorac, chloropon, dalapon, flupropanate, hexachloroacetone, iodomethane, methyl bromide, monochloroacetic acid, SMA, TCA
30.
Imidazolinone herbicides: imazamethabenz, imazamox,
imazapic, imazapyr, imazaquin, imazethapyr
31.
Inorganic herbicides:
ammonium sulfamate, borax, calcium chlorate, copper sulfate, ferrous sulfate, potassium azide, potassium cyanate, sodium azide, sodium chlorate, sulfuric acid
32.
Nitrile herbicides: bromobonil, bromoxynil, chloroxynil,
dichlobenil, iodobonil, ioxynil, pyraclonil
33.
Organophosphorus herbicides: amiprofos-methyl, anilofos,
bensulide, bilanafos, butamifos, 2,4-DEP, DMPA, EBEP, fosamine, glufosinate, glufosinate-P, glyphosate, piperophos
34.
Oxadiazolone herbicides: dimefuron, methazole, oxadiargyl,
oxadiazon
35.
Oxazole herbicides: carboxazole, fenoxasulfone, isouron, isoxaben, isoxachlortole, isoxaflutole, methiozolin, monisouron, pyroxasulfone, topramezone
13
36.
Phenoxy herbicides: bromofenoxim, clomeprop, 2,4-DEB, 2,4DEP, difenopenten, disul, erbon, etnipromid, fenteracol, trifopsime a. Phenoxyacetic herbicides: 4-CPA, 2,4-D, 3,4-DA, MCPA, MCPA-thioethyl, 2,4,5-T b. Phenoxybutyric herbicides: 4-CPB, 2,4-DB, 3,4-DB, MCPB, 2,4,5-TB, c. Phenoxypropionic herbicides: cloprop, 4-CPP, dichlorprop, dichlorprop-P, 3,4-DP, fenoprop, mecoprop, mecoprop-P
37.
Aryloxyphenoxypropionic herbicides:
chlorazifop, clodinafop, clofop, cyhalofop, diclofop, fenoxaprop, fenoxaprop-P, fenthiaprop, fluazifop, fluazifop-P, haloxyfop, haloxyfop-P, isoxapyrifop, metamifop, propaquizafop, quizalofop, quizalofop-P, trifop
38.
Phenylenediamine herbicides: dinitramine, prodiamine
39.
Pyrazole herbicides: azimsulfuron, difenzoquat, halosulfuron,
metazachlor, metazosulfuron, pyrazosulfuron, pyroxasulfone
a. Benzoylpyrazole herbicides: benzofenap, pyrasulfotole, pyrazolynate, pyrazoxyfen, topramezone b. Phenylpyrazole herbicides: fluazolate, nipyraclofen, pinoxaden, pyraflufen
40.
Pyridazine herbicides: credazine, pyridafol, pyridate
41.
Pyridazinone herbicides: brompyrazon, chloridazon, dimidazon,
flufenpyr, metflurazon, norflurazon, oxapyrazon, pydanon
42.
Pyridine herbicides: aminopyralid, cliodinate, clopyralid,
diflufenican, dithiopyr, flufenican, fluroxypyr, haloxydine, picloram, picolinafen, pyriclor, pyroxsulam, thiazopyr, triclopyr
43.
Pyrimidinediamine herbicides: iprymidam, tioclorim
44.
Quaternary ammonium herbicides: cyperquat, diethamquat,
difenzoquat, diquat, morfamquat, paraquat
45.
Thiocarbamate herbicides: butylate, cycloate, di-allate, EPTC,
esprocarb, ethiolate, isopolinate, methiobencarb, molinate, orbencarb, pebulate, prosulfocarb, pyributicarb, sulfallate, thiobencarb, tiocarbazil, trillate, vernolate
46.
Thiocarbonate herbicides: dimexano, EXD, proxan 14
47.
Thiourea herbicides: methiuron
48.
Triazine herbicides: dipropetryn, trihydroxytriazine i. Chlorotriazine herbicides: atrazine, chlorazine, cyanazine, cyprazine, eglinazine, ipazine, mesoprazine, procyazine, proglinazine, propazine, sebuthylazine, simazine, terbuthylazine, trietazine ii. Fluoroalkyltriazine herbicides: indaziflam, triaziflam iii. Methoxytriazine herbicides: atraton, methometon, prometon, secbumeton, simeton, terbumeton iv. Methylthiotriazine herbicides: ametryn, aziprotryne, cyanatryn, desmetryn, dimethametryn, methoprotryne, prometryn, simetryn, terbutryn
49.
Triazinone herbicides: ametridione, amibuzin, hexazinone, isomethiozin, metamitron, metribuzin
50.
Triazole herbicides: amitrole, cafenstrole, epronaz, flupoxam
51.
Triazolone herbicides: amicarbazone, bencarbazone,
carfentrazone, flucarbazone, ipfencarbazone, propoxycarbazone, sulfentrazone, thiencarbazone
52.
Triazolopyrimidine herbicides: cloransulam, diclosulam, florasulam, flumetsulam, metosulam, penoxsulam, pyroxsulam
53.
Uracil herbicides: benzfendizone, bromacil, butafenacil, flupropacil, isocil, lenacil, saflufenacil, terbacil
54.
Urea herbicides: benzthiazuron, cumyluron, cycluron, dichloralurea, diflufenzopyr, isonoruron, isouron, methabenzthiazuron, monisouron, noruron i. Phenylurea herbicides: anisuron, buturon, chlorbromuron, chloreturon, chlorotoluron, chloroxuron, daimuron, difenoxuron, dimefuron, diuron, fenuron, fluometuron, fluothiuron, isoproturon, linuron, methiuron, methyldymron, metobenzuron, metobromuron, metoxuron,monolinuron, monuron, neburon, parafluron, phenobenzuron, siduron, tetrafluron, thidiazuron
15
ii. Sulfonylurea herbicides: a. Pyrimidinylsulfonylurea herbicides: amidosulfuron, azimsulfuron, bensulfuron, chlorimuron, cyclosulfamuron, ethoxysulfuron, flazasulfuron, flucetosulfuron, flupyrsulfuron, foramsulfuron, halosulfuron, imazosulfuron, mesosulfuron, metazosulfuron, nicosulfuron, orthosulfamuron, oxasulfuron,primisulfuron, propyrisulfuron, pyrazosulfuron, rimsulfuron, sulfometuron, sulfosulfuron, trifloxysulfuron
b. Triazinylsulfonylurea herbicides: chlorsulfuron, cinosulfuron, ethametsulfuron, iodosulfuron, metsulfuron, prosulfuron, thifensulfuron, triasulfuron, tribenuron, triflusulfuron, tritosulfuron
iii. Thiadiazolylurea herbicides: buthiuron, ethidimuron, tebuthiuron, thiazafluron, thidiazuron
55.
Unclassified herbicides: acrolein, allyl alcohol, aminocyclopyrachlor, azafenidin, bentazone, benzobicyclon, bicyclopyrone, buthidazole, calcium cyanamide, cambendichlor, chlorfenac, chlorfenprop, chlorflurazole, chlorflurenol, cinmethylin, clomazone, CPMF, cresol, cyanamide, ortho-dichlorobenzene, dimepiperate, endothal, fluoromidine, fluridone, flurochloridone, flurtamone, fluthiacet, indanofan, methyl isothiocyanate, OCH, oxaziclomefone, pelargonic acid, pentachlorophenol, pentoxazone, phenylmercury acetate, prosulfalin, pyribenzoxim, pyriftalid, quinoclamine, rhodethanil, sulglycapin, thidiazimin, tridiphane, trimeturon, tripropindan, tritac
16
Some Gametocides Male gametocides are widely used in breeding programs and for hybrid seed production in crops which present difficulty in hand emasculation of bisexual flowers. The gametocides may be general or crop specific however proper growth stage of application is crucial for effective sterilization of male parts. Here general introduction of some common gametocides is given to have background information on working of gametocides. 1. Clofencet It is a branded product of Monsanto Company marketed as Genesis® hybridizing agent for wheat and as herbicide. Other trade names are MON 21200 Technical and MON 21233 Manufacturing Use Product. The generic name of the product is 2-(4-chlorophenyl)-3-ethyl-2,5dihydro-5-oxo-4-pyridazinecarboxylic acid, potassium salt expressed as the free acid. This chemical suppresses normal pollen development in female wheat plants without affecting fertility, allowing for cross-pollination by adjacent untreated wheat plants. Method of Application: Application rates for wheat between tip emergence of the penultimate leaf (Feekes Scale 7.0, Zadoks Scale 32) and emergence of the flag leaf ligule (Feekes Scale 9.0, Zadoks Scale 39) range from 3 to 50 gallons (3 to 6 lbs. active ingredient) per acre and is applied once per growing season.
17
Reapplication is permitted if rainfall occurs within 24 hours of application but the total of all applications and reapplications must not exceed 10 lbs active ingredient per acre per season. Application of Genesis® must be made at least 45 days prior to the harvest of the hybrid wheat seed. 2. DABCO The active compounds are primarily quaternary salts of the compound 1,4-diazabicyclo (2.2.2) octane (DABCO). DABCO is a known compound, as are some of its halogen derivatives. Some of the known uses for DABCO compounds are as antibacterial agents, or for ganglion blocking and as a central nervous system depressant. It has previously not been known to use DABCO or its quaternary salts in the process of inducing male sterility in plants, however. The useful salts may be mono-or-di-quaternary salts of DABCO. Particularly preferred are the halogen derivatives of DABCO, and most preferred are DABCO-benzyl chloride, and DABCO-BCl3. The DABCO compound itself is also contemplated for use in the present method. The process of male sterility induction is implemented by the treatment of seeds of a plant possessing characteristics which are deemed desirable for the specific purpose, with DABCO or one of its quaternary salts. The treatment serves, in a manner which is not yet certain, to prevent pollen formation in the adult plant which is ultimately derived from a treated seed. Thus is provided a stand of plants which is functionally all female, and which can then be selectively hybridized by pollination by a plant having different features which may be desirable to incorporate into the genome of the male sterilized plant. The resulting hybrid seed contains the superior traits of both the all-female plants and the selected plant by which it was pollinated. Therefore, the resulting seeds would produce adult plants which are superior to both parent plants in that the desirable traits of each are combined into a single plant. The present process is particularly well-suited for plants which are generally selffertilizing, such as wheat. 18
The treatment of the seeds is a relatively simple process. The DABCO salts are generally dissolved in a hydrocarbon carrier solvent, such as carbon tetrachloride or benzene, DMSO, or water. Particularly preferred solvent is DMSO (dimethylsulfoxide) at a concentration of 0.2-20% preferably about 5%. DMSO is preferred because of its independent effect of inducing some level of male sterility. The active ingredient is added to the carrier to produce a final concentration within the range of 0.01-100 millimolar, with the preferred concentration being about 1 mM. The remaining volume of the solution is made up with double distilled water. The seeds to be used may be surface sterilized prior to their treatment with the chemisterilant. The seeds may be placed in any suitable container, such as a petri dish, and the active chemical solution added. As the present compounds tend to deteriorate with time, and may yield unpredictable or unwanted results when left for long periods of time, it is generally preferred to use relatively fresh preparations. In some cases, depending upon the thickness of the seed coat, it is desirable to scarify the seeds to expedite entry of the treatment solution before germination. The amounts needed for treatment may vary, but generally 2 ml/20 seeds are sufficient to produce the desired result. The seeds may then be covered and incubated in a growth chamber for a period of at least 24 hours. The seeds may then be placed in soil and maintained in a manner consistent with the usual growing conditions for the plant in question. The plants are allowed to mature, and pollination procedures of various types well-known in the field may be employed upon ripening of the female plant, to produce the desired hybrid seed. The treatment prescribed herein may be applied to a wide variety of seed types, although, to date, best results have been observed with monocot seeds. The present method has been particularly successful with wheat seeds. However, the process is, in principle, applicable to any type of plant seed. Whether the present method is useful in producing male sterility in any given seed type may be readily determined by following the above-outlined procedure. After the treated seeds have been planted and grown to maturity, it is a relatively simple matter, particularly in self-fertilizing plants, to observe the seed set of the plants derived from the treated seeds. Absence or reduction of seed set indicates the effectiveness of 19
inducing sterility by the treatment. Certain modifications of the abovementioned protocol may be required to obtain completely satisfactory results. For example, concentration of the active ingredient, or length of incubation may have to be varied depending upon the type of seed used. It is, however, easily within the ability of one skilled in the art to determine the appropriate adjustments which will render the treatment most effective. The advantages of the use of the present compounds over previously known chemical sterilizing agents are many. First, they may be applied directly to the seeds, rather than as a foliar spray to adult plants. This avoids both the problems of environmental pollution, and the necessity of synchrony with the exact stage of plant development. They have also proven useful in producing male sterility in wheat, a plant which has traditionally resisted efforts to establish male sterile lines. Also, the compounds appear to have little or no effect on female fertility in plants grown from treated seeds. The present invention will become more clearly understood by reference to the following non-limiting examples. 3. EMBUTOX: Embutox is 2, 4-Dichlorophenoxybutyric acid and is part of the group of acetic, propionic, butyric and isobutyric acids and their chlorosubstituted derivatives which have established or potential use as food preservatives, herbicides and plant gametocides. Dichlorosubstituted acetic acid has been widely used for inducing malesterility in cucumber, watermelon, sorghum, tomato and tobacco. Dichloro-substituted butyric acid is known phytogametocide for okra, kenaf, coriander and fennel with varying phytotoxic symptoms. 4. Glutathione: Reduced Glutathione (GSH) is a linear tripeptide of L-glutamine, Lcysteine, and glycine. Technically N-L-gamma-glutamyl-cysteinyl glycine or L-Glutathione, the molecule has a sulfhydryl (SH) group on the cysteinyl portion, which accounts for its strong electron-donating character.
20
As electrons are lost, the molecule becomes oxidized, and two such molecules become linked (dimerized) by a disulfide bridge to form Glutathione disulfide or oxidized Glutathione (GSSG). This linkage is reversible upon re-reduction. Glutathione is under tight homeostatic control both intracellular and extracellular. A dynamic balance is maintained between GSH syntheses, it’s recycling from GSSG/oxidized Glutathione, and its utilization. Glutathione synthesis involves two closely linked, enzymaticallycontrolled reactions that utilize ATP. First, cysteine and glutamate are combined by gamma-glutamyl cysteinyl synthetase. Second, GSH synthetase combines gamma-glutamylcysteine with glycine to generate Glutathione. As Glutathione levels rise, they self-limit further GSH synthesis; otherwise, cysteine availability is usually rate-limiting. Fasting, protein-energy malnutrition, or other dietary amino acid deficiencies limit Glutathione synthesis. Glutathione recycling is catalyzed by Glutathione disulfide reductase, which uses reducing equivalents from NADPH to reconvert GSSG to 2GSH. The reducing power of ascorbate helps conserve systemic Glutathione. Glutathione is used as a cofactor by (1) multiple peroxidase enzymes, to detoxify peroxides generated from oxygen radical attack on biological molecules; (2) transhydrogenases, to reduce oxidized centers on DNA, proteins, and other biomolecules; and (3) Glutathione S-transferases (GST) to conjugate Gluathione with endogenous substances (e.g., estrogens), exogenous electrophiles (e.g., arene oxides, unsaturated carbonyls, organic halides), and diverse xenobiotics. Low GST activity may increase risk for disease— but paradoxically, some Glutathione conjugates can also be toxic. Essential GSH™ is a breakthrough liquid formulation uniquely designed to increase the systemic bioavailability of Glutathione, via a liposomal-based delivery. It provides Glutathione in a convenient, absorbable form that your body can rapidly use using pharmaceutical grade liposomes. Because liposomes are made from the same material that your cell membranes are made from, it fuses with cell membranes and allows for absorption of Glutathione into the cells.
21
Basically the drug is used in treatment of cancer, HIV, diabetes and heavy metal toxicity but experiments carried out by B. Adinaryayana and P. Gopala (Sri Venkateswara University, Tirupati, India, Current Science April 20, 1989) have shown that Gibberellic acid (GA3) and Glutathione (GSH) together totally inhibited flowering in okra. In the same study it was found that GA3, cysteine, methionine and GSH acted as potent male gametocides. Many enzymes and proteins are inactivated by sulfhydryl-binding reagents. GA3 is considered as an activator or inhibitor of protein synthesis acting at the translational level. Gibberellic acid (GA3) and Glutathione (GSH) together reduced the size of inflorescence and totally inhibited petal formation in Tridex procumbens L. GA3 treatment reduced size of ray flowers in Begonia but enhanced in Gaillardia so response differs in different plants. GA3 treatment totally suppresses corolla formation in Tridex procumbens L. but its interaction with GSH significantly enlarges corolla growth. GA3 treatment induces male sterility in disc florets of Tridex procumbens as has been observed in okra and maize. 5. Maleic Hydrazide: It is a plant growth regulator with chemical formula C4H4N2O2 and varying formulations like 6-hydroxy-2H-pyridazin-3-one or 1,2dihydropyridazine-3,6-dione or 1,2-dihydro-3,6-pyridazinedione. Primary uses include sucker control on tobacco, sprout inhibition in stored onions and potatoes, frost protection in citrus and turf and roadside maintenance. Maleic hydrazide has herbicidal activity on quackgrass, wild onions, and wild garlic (Weed Science Society of America, Herbicide Handbook Committee. 1983. Herbicide handbook of the weed science society of America, 5th ed. Weed Science Society of America, Champaign, IL. 515 pp.). Maleic hydrazide is recommended for the temporary growth inhibition of various trees, shrubs and grasses (Farm Chemicals Handbook, 70th ed. 1984. R. T. Meister, G. L. Berg, C. Sine, S. Meister, and J. Poplyk, eds. Meister Publishing Co., Willoughby, OH.). Used as a over-the-top foliar spray. Dosage and stage of plant development are critical factors (Farm Chemicals Handbook, 70th ed. 1984.). 22
Experiments with coriander have shown that spraying of Maleic Hydrazide at 125 ppm results in suppression of anther dehiscence due to severe agglutination of the pollen. Repeating spray of Maleic Hydrazide at 100 ppm from 25 DAS on wards until the cessation of flowering causes suppression of anther dehiscence during entire flowering period. Successful crosses were obtained using Maleic Hydrazide as chemical emasculation agent. Experimental observations on the use of gametocides on vegetable crops are reviewed. Out of 15 chemicals tested MH (maleic hydrazide) at 100 to 500 p.p.m. appeared most effective in inducing a high level of pollen sterility in eggplant, okra, peppers and tomato, without detrimental influence on female fertility. Mendok (2,3dichloroisobutyrate), between 0.2 and 0.8%, also caused a high degree of pollen sterility, but was accompanied by an adverse influence on plant vigor and fruit-set. (Scientia Horticulturae Volume 8, Issue 1, January 1978, Pages 11-17) 7. Ethylene: Experiments with hemp crop have shown that treatment of hempseed with ethylene gas will increase the resulting number of female plants by about 50%. Ethylene is produced by certain plants (i.e., bananas, cucumbers and melons), and these can be used to treat hempseed in a simple manner. About two weeks before you plan to sprout the seeds, place them in a paper bag or envelope and put that in a plastic bag with the peels of a ripening banana or cucumber. Replace the peels after a couple of days, and change the bags to prevent mold. 8. Ethephon: Ethephon is the common name of the most widely used plant growth regulator (basic manufacturer Rhône-Poulenc now Bayer Crop Science). Upon metabolism by the plant, it is converted into ethylene, a potent regulator of plant growth and maturity. It is often used on wheat, coffee, tobacco, cotton and rice in order to help the plant's fruit reach maturity more quickly. In cotton, most important single crop for 23
the use of Ethephon, which initiates fruiting over a period of several weeks, ethephon is used to promote early concentrated boll opening and enhance defoliation to facilitate and improve efficiency of scheduled harvesting. Harvested cotton quality is improved. Although many environmental groups worry about toxicity resulting from use of growth hormones and fertilizers, the toxicity of ethephon is actually very low (Pesticide Information Profiles: Ethephon. Extension Toxicology Net. Sept 1995) and any ethephon used on the plant material is converted very quickly to ethylene ("1994 Joint meeting of the FAO panel of experts on pesticide residues in food and the environment." UN Food and Agriculture Organization. 1994). 9. FW-450: Evaluation of Sodium 2, 3-Dichloroisobutyrate (FW-450) as a Selective Male Gametocide in Cotton and okra has been done by various researchers with partial success. The use of chemicals in inducing male sterility has recently received attention. Sodium 2,3-dichloroiosobutyrate (FW-450) has been of special interest to plant breeders. Hensz and Mohr (10) were able to completely eliminate the opening of staminate flowers in watermelons with concentrations of 0.25 and 0.50 percent FW-450. While working with lettuce, Foster and Murdock (Foster, R. E. and E. L. Murdock. 1960. Lettuce breeding and gametocide studies. Lettuce Res. Rep. Arizona No. 189:35-36) did not find any development of anthers following the treatment with FW-450. Pate and Duncan (Pate, J. B. and E. N. Duncan; 1960: Evaluation of sodium 2,3dichloroisobutyrate as a selective male gametocide in cotton. Agron. Jour. 52:506-508) have made extensive studies with FW-450 on cotton and significant results were obtained in inducing male sterility but the gametocide was reported to be phytotoxic at very high concentrations. Recently Scott (Scott, R. A. Jr. 1961. Mechanism and reversal of gametocide response in cotton. P. Phys. 36: 529-538) studying the 24
mechanism and reversal of sodium 2,2-dichloroisopropionate (Dalapan) and FW-450, reported that the exogenous application of these gametocides to cotton plants induced non-dehiscent anthers.
Classification of Plant Growth Regulators Plant growth regulators including defoliants are generally used to regulate the growth of the plants through various modes of action but it has been observed that such chemicals too have good potential for use as chemical hybridizing agents. Therefore before selecting appropriate chemical for specific crop it is useful to understand classification of the plant growth regulators. Main groups of Plant growth regulators are detailed below: •
antiauxins:
1. clofibric acid = 2-(4-chlorophenoxy)-2-methylpropionic acid 2. 2,3,5-tri-iodobenzoic acid = 2,3,5-triiodobenzoic acid (TIBA) •
auxins:
1. 4-CPA = 4-chlorophenoxyacetic acid 2. 2,4-D = (2,4-dichlorophenoxy)acetic acid 3. 2,4-DB = 4-(2,4-dichlorophenoxy)butyric acid 4. 2,4-DEP = tris[2-(2,4-dichlorophenoxy)ethyl] phosphite 5. dichlorprop = 2-(2,4-dichlorophenoxy)propanoic acid 6. fenoprop = 2-(2,4,5-trichlorophenoxy)propanoic acid 7. IAA = indol-3-ylacetic acid or β-indoleacetic acid 8. IBA = 4-indol-3-ylbutyric acid or 1H-indole-3-butanoic acid 9. naphthaleneacetamide = 2-(1-naphthyl)acetamide or 25
1-naphthaleneacetamide [There is no ISO common name for this substance; the names “naphthaleneacetamide” and “NAAm” have been used in the literature but have no official status.] 10. α-naphthaleneacetic acid = 1-naphthylacetic acid or 1-naphthaleneacetic acid: The name “NAA” has also been used in the literature. 11. 1-naphthol = 1-naphthol or 1-naphthalenol 12. naphthoxyacetic acids = (1-naphthyloxy)acetic acid or (2-naphthyloxy)acetic acid 13. potassium naphthenate 14. sodium naphthenate 15. 2,4,5-T = (2,4,5-trichlorophenoxy)acetic acid •
cytokinins
1. 2iP = N6-(3-methylbut-2-enyl)adenine or N-(3-methylbut-2-enyl)-1H-purin-6-amine 2. benzyladenine = N-benzyl-1H-purin-6-amine 3. kinetin = N-furfuryl-1H-purin-6-amine 4. zeatin = (E)-2-methyl-4-(9H-purin-6-ylamino)but-2-en-1-ol •
defoliants:
1. calcium cyanamide 2. dimethipin = 2,3-dihydro-5,6-dimethyl-1,4-dithiine 1,1,4,4-tetraoxide 3. endothal = 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid 4. ethephon = 2-chloroethylphosphonic acid 5. merphos = tributyl phosphorotrithioite 26
6. metoxuron = 3-(3-chloro-4-methoxyphenyl)-1,1-dimethylurea 7. pentachlorophenol =
Salt = sodium pentachlorophenoxide. Methylmercury derivative = methylmercury pentachlorophenoxide. 8. thidiazuron = 1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea 9. tribufos = S,S,S-tributyl phosphorotrithioate (the names
“butifos” and “merphos oxide” have been used for this substance, but have no official status) •
ethylene inhibitors:
1. aviglycine = (E)-L-2-[2-(2-aminoethoxy)vinyl]glycine or
(2S,3E)-2-amino-4-(2-aminoethoxy)-3-butenoic acid 2. 1-methylcyclopropene = 1-methylcyclopropene (the names “1MCP”, and “MCP” have also been used in the literature but have no official status •
ethylene releasers:
1. ACC = 1-aminocyclopropanecarboxylic acid 2. etacelasil = 2-chloroethyltris(2-methoxyethoxy)silane 3. ethephon 4. glyoxime = glyoxal dioxime or ethanedial dioxime •
Gibberellins:
1. gibberellins 2. gibberellic acid = (3S,3aS,4S,4aS,7S,9aR,9bR,12S)-7,12-
dihydroxy-3-methyl-6-methylene-2-oxoperhydro-4a,7-methano9b,3-propenoazuleno[1,2-b]furan-4-carboxylic acid or 27
•
(3S,3aR,4S,4aS,6S,8aR,8bR,11S)-6,11-dihydroxy-3-methyl-12methylene-2-oxo-4a,6-ethano-3,8b-prop-1enoperhydroindeno[1,2-b]furan-4-carboxylic acid growth inhibitors:
1. abscisic acid = (2Z,4E)-5-[(1S)-1-hydroxy-2,6,6-trimethyl-4-
oxocyclohex-2-en-1-yl]-3-methylpenta-2,4-dienoic acid; or (7E,9Z)-(6S)-6-hydroxy-3-oxo-11-apo-ε-caroten-11-oic acid 2. ancymidol = (RS)-α-cyclopropyl-4-methoxy-α-(pyrimidin-5-
yl)benzyl alcohol; or α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol 3. butralin = (RS)-N-sec-butyl-4-tert-butyl-2,6-dinitroaniline; or 4-
(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamine 4. carbaryl = 1-naphthyl methylcarbamate 5. chlorphonium = tributyl(2,4-dichlorobenzyl)phosphonium 6. chlorpropham = isopropyl 3-chlorocarbanilate; or 1-methylethyl
(3-chlorophenyl)carbamate 7. dikegulac = 2,3:4,6-di-O-isopropylidene-α-L-xylo-2-
hexulofuranosonic acid; or 2,3:4,6-bis-O-(1-methylethylidene)α-L-xylo-2-hexulofuranosonic acid 8. flumetralin = N-(2-chloro-6-fluorobenzyl)-N-ethyl-α,α,α-trifluoro-
2,6-dinitro-p-toluidine; or 2-chloro-N-[2,6-dinitro-4(trifluoromethyl)phenyl]-N-ethyl-6-fluorobenzenemethanamine 9. fluoridamid = 3′-(1,1,1-trifluoromethanesulfonamido)acet-p-
toluidide; or N-[4-methyl-3[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide 10. fosamine = ethyl hydrogen carbamoylphosphonate; or ethyl
hydrogen (aminocarbonyl)phosphonate 11. glyphosine = N,N-bis(phosphonomethyl)glycine 28
12. isopyrimol = (RS)-1-(4-chlorophenyl)-2-methyl-1-pyrimidin-5-
ylpropan-1-ol; or α-(4-chlorophenyl)-α-(1-methylethyl)-5pyrimidinemethanol 13. jasmonic acid = (1R,2R)-3-oxo-2-(Z)-pent-2-
enylcyclopentylacetic acid 14. maleic hydrazide = 6-hydroxy-2H-pyridazin-3-one; or
1,2-dihydropyridazine-3,6-dione; or 1,2-dihydro-3,6pyridazinedione 15. mepiquat = 1,1-dimethylpiperidinium 16. piproctanyl = (RS)-1-allyl-1-(3,7-dimethyloctyl)piperidinium 17. prohydrojasmon = propyl (1RS,2RS)-(3-oxo-2-
pentylcyclopentyl)acetate containing 10±2% propyl (1RS,2SR)(3-oxo-2-pentylcyclopentyl)acetate; or propyl (1R,2R)-rel-3-oxo2-pentylcyclopentaneacetate 18. propham = isopropyl carbanilate; or isopropyl phenylcarbamate 19. 2,3,5-tri-iodobenzoic acid = o
Morphactins:
1. chlorfluren = (RS)-2-chlorofluorene-9-carboxylic acid 2. chlorflurenol = (RS)-2-chloro-9-hydroxyfluorene-9carboxylic acid 3. dichlorflurenol = 2,7-dichloro-9-hydroxyfluorene-9carboxylic acid 4. flurenol = 9-hydroxyfluorene-9-carboxylic acid (the name “flurecol” is used in Canada, Denmark and the USA, and was formerly approved by the British Standards Institution)
29
•
growth retardants:
1. chlormequat = 2-chloroethyltrimethylammonium; or 2-chloro-
N,N,N-trimethylethanaminium 2. daminozide = N-(dimethylamino)succinamic acid; or
butanedioic acid mono(2,2-dimethylhydrazide) 3. flurprimidol = (RS)-2-methyl-1-pyrimidin-5-yl-1-(4-
trifluoromethoxyphenyl)propan-1-ol; or α-(1-methylethyl)-α-[4(trifluoromethoxy)phenyl]-5-pyrimidinemethanol 4. mefluidide = 5′-(1,1,1-trifluoromethanesulfonamido)acet-2′,4′-
xylidide; or N-[2,4-dimethyl-5[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide 5. paclobutrazol = (2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-
(1H-1,2,4-triazol-1-yl)pentan-3-ol; or (αR,βR)-rel-β-[(4chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1ethanol 6. tetcyclacis = rel-(1R,2R,6S,7R,8R,11S)-5-(4-chlorophenyl)-3,4,5,9,10pentaazatetracyclo[5.4.1.02,6.08,11]dodeca-3,9-diene; or (3aR,4R,4aS,6aR,7R,7aS)-rel-1-(4-chlorophenyl)-3a,4,4a,6a,7,7ahexahydro-4,7-methano-1H-[1,2]diazeto[3,4-f]benzotriazole 7. uniconazole = (E)-(RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-
1,2,4-triazol-1-yl)pent-1-en-3-ol; or (βE)-β-[(4chlorophenyl)methylene]-α-(1,1-dimethylethyl)-1H-1,2,4triazole-1-ethanol •
growth stimulators:
1. brassinolide = (3aS,5S,6R,7aR,7bS,9aS,10R,12aS,12bS)-10-
[(1S,2R,3R,4S)-2,3-dihydroxy-1,4,5trimethylhexyl]hexadecahydro-5,6-dihydroxy-7a,9a-dimethyl3H-benzo[c]indeno[5,4-e]oxepin-3-one 2. forchlorfenuron = 1-(2-chloro-4-pyridyl)-3-phenylurea
30
3. hymexazol = 5-methylisoxazol-3-ol; or 5-methyl-1,2-oxazol-3-ol •
unclassified plant growth regulators:
1. benzofluor = 4′-ethylthio-2′-(trifluoromethyl)methylsulfonanilide;
or N-[4-(ethylthio)-2(trifluoromethyl)phenyl]methanesulfonamide 2. buminafos = dibutyl 1-butylaminocyclohexylphosphonate 3. carvone = (RS)-5-isopropenyl-2-methylcyclohex-2-en-1-one; or
(RS)-p-mentha-6,8-dien-2-one; or 2-methyl-5-(1methylethenyl)-2-cyclohexen-1-one 4. ciobutide = (RS)-2-cyano-2-phenylbutyramide; or α-cyano-α-
ethylbenzeneacetamide 5. clofencet = 2-(4-chlorophenyl)-3-ethyl-2,5-dihydro-5-
oxopyridazine-4-carboxylic acid 6. cloxyfonac = 4-chloro-α-hydroxy-o-tolyloxyacetic acid 7. cyanamide = CH2N2 8. cyclanilide = 1-(2,4-dichloroanilinocarbonyl)cyclopropanecarboxylic acid 9. cycloheximide = 4-{(2R)-2-[(1S,3S,5S)-3,5-dimethyl-2-
oxocyclohexyl]-2-hydroxyethyl}piperidine-2,6-dione 10. cyprosulfamide = N-[4-(cyclopropylcarbamoyl)phenylsulfonyl]-
o-anisamide; or N-[4-(cyclopropylcarbamoyl)phenylsulfonyl]-2methoxybenzamide 11. epocholeone = 22,23-epoxy-6-oxo-7-oxa-6(7a)-homo-5α-
stigmastane-2α,3α-diyl dipropionate 12. ethychlozate = ethyl 5-chloro-3(1H)-indazolylacetate 13. ethylene = C2H4
31
14. fenridazon = 1-(4-chlorophenyl)-1,4-dihydro-6-methyl-4-
oxopyridazine-3-carboxylic acid 15. heptopargil = (1RS,4RS)-bornan-2-one (E)-O-prop-2-ynyloxime 16. holosulf = 2-chloroethanesulfinic acid 17. inabenfide = (RS)-4′-chloro-2′-(α-
hydroxybenzyl)isonicotinanilide; or N-[4-chloro-2(hydroxyphenylmethyl)phenyl]-4-pyridinecarboxamide 18. karetazan = 2-(4-chlorophenyl)-1-ethyl-1,4-dihydro-6-methyl-4-
oxonicotinic acid 19. lead arsenate = lead arsenate; or lead hydrogenarsenate; or
arsenic acid (H3AsO4) lead(2+) salt (1:1) 20. methasulfocarb = S-4-(mesyloxy)phenyl methyl(thiocarbamate);
or S-[4-[(methylsulfonyl)oxy]phenyl] methylcarbamothioate 21. prohexadione = 3,5-dioxo-4-propionylcyclohexanecarboxylic acid 22. pydanon = (RS)-hexahydro-4-hydroxy-3,6-dioxopyridazin-4-
ylacetic acid; or hexahydro-4-hydroxy-3,6-dioxo-4pyridazineacetic acid 23. sintofen = 1-(4-chlorophenyl)-1,4-dihydro-5-(2-methoxyethoxy)-
4-oxocinnoline-3-carboxylic acid 24. triapenthenol = E)-(RS)-1-cyclohexyl-4,4-dimethyl-2-(1H-1,2,4-
triazol-1-yl)pent-1-en-3-ol; or (βE)-β-(cyclohexylmethylene)-α(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol 25. trinexapac = RS)-4-cyclopropyl(hydroxy)methylene-3,5-
dioxocyclohexanecarboxylic acid
32
Priority Crops for CHA Studies Family Cucurbitaceae: 1. Bitter gourd 2. Round gourd 3. Watermelon 4. Musk Melon Family Brassicaceae: 1. Cauliflower 2. Radish
Family Solanaceae: 1. Tomato 2. Eggplant 3. Chili and Sweet pepper Others: 1. Onion 2. Carrot 3. Peas 4. Okra 33
Work Plan for the Months of February-March, 2010 February: 1. Review of literature on CHA technology for cucurbits 2. Identification of suitable chemical hybridization agents for cucurbits. 3. Acquiring requisite chemicals. 4. Developing design of studies in respect of timings of application and range of dosages. 5. Arrangements for managed environment facility. March: 1. Selection of three sites with different temperature regimes and planting of material. 2. Application of chemicals as per schedule. 3. Arrangements for managed environment facility (continued). 4. Observations: a) Impact on general plant growth and toxicology. b) Impact on male gametes c) Impact on female fertility d) Impact on seed setting (at later stage) ------------------------------ End of First Report ------------------------------
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