how long does it take for celebrex to start working side effects of ophthacare what does atarax treat micardis now co uk can order compazine canada sarafem women buy kroger pharmacy jobs ohio overnight trazodone can trazodone get you high order forzest cheap actoplus met sale uk what does synthroid dose top 10 indian pharmaceutical companies 2012 buy viagra soft boots pharmacy what are the most common side effects of digoxin toxicity in the elderly buy generic benicar hct buy biaxin online amazon canadian pharmacy alphagan generic exelon safe mental health anxiety duphalac dry bijsluiter low cost actos generic pariet tablets from buy lasuna online pay paypal what are the side effects of procardia buy propecia online prescription buy diclofenac gel mg how long do you have to take zyban aciclovir online meds how much is colospa tablets 40 mg decadron side effects pharmacy placements 2013 revia buy online ireland what is the classification of micronase lincocin no prescription compare prices us pharmacy online benicar how do you take cytotec for an abortion acivir pills dosage recommended redustat sirve fluoxetine veterinary medicine clomid tablets 40mg bentyl without a prescription buy amaryl in uk cephalexin tablets for cats xenical with paypal hydrea cost in canada zyprexa cost comparison underactive thyroid medication australia purchase furosemide in mexico overnight free shipping view topic aldactone prandin without rx cardizem visa co-azithromycin 250 mg and alcohol actoplus met prices at costco roxithromycin overnight delivery buy amaryl generic current price brand levitra buy nitrofurantoin australia cheap pariet buy online like viagra but natural glucophage mail order cleocin gel online sales overseas pharmacy no prescription trental orlistat approved in canada citalopram withdrawal headache cialis generic versus brand name cephalexin for dogs dosage what is mestinon drugs bringing viagra mexico canada generic lotrisone lotion why has carbozyne been discontinued levlen buy on line neurontin 600 mg.50 film tablet voltaren free shipping lamictal woldwide shipping do you need rx purim i want to pay some unisom clorfenamina tabletas plm dostinex without a prescription order zocor from canada without prescription compazine mist canada myambutol tablets buy generic acivir pills online cialis sublingual woldwide shipping buy cytoxan perth australia abilify on line in the usa biaxin overnight pharmacy xenical capsules patient information clomid for daily use canada purchasing decadron online buy benadryl d online levothroid 100mg tablet buy ranitidine usa best place to order aricept in us liquid aleve review comprar remedio vytorin ortho tri-cyclen australia pharmacy hydrochlorothiazide prescription buy online side effects propecia order generic adalat zetia price walmart buy betapace pills viagra femenina venta en texas florida retin-a 0,05 american express canada travel services generic suprax cefixime actoplus met echeck buy water pills toronto order lantus insulin online what class of drugs is plavix buy online fincar generic exelon refills increasing lexapro dosage headache estrace 2 mg tablet generic flovent safe buy accutane 50 betapace 50mg tablets do doctors prescribe viagra performance anxiety lopid in the uk viagra cobra 125 viagra jelly medication order lamictal side effects weight robaxin to buy in the usa without a prescription can i make maxaman best site to buy zyprexa kamagra oral jelly order in the us can you order aceon rocaltrol shelf life minocycline pigmentation treatment viragra cheap no prescription overnight what is femara 2.5mg aldactone 20mg tab lexapro generic launch date buy cymbalta from canada generic tofranil buy canada roxithromycin dosage for uti buy arimidex from india myambutol canada prescription order viagra plus 120 mg bactroban salep kulit generic uk paypal beconase aq viagra no prescription usa long time sex tablet name in bangladesh brand sale cialis online drug order lamisil online no prescription free shipping ventolin order by phone lisinopril from australia generic maxalt online zyprexa generic cheap costs hire purchase alliance bank generic viagra reviews australia domperidone no rx colospa tablets online through buy albendazole tablets generic mircette names bystolic and lisinopril combination where to buy accutane no prescription drugs what is propranolol 10 mg tablet and what are the side effects what are the side effects of stopping paroxetine is there a drug comparative to zovirax buy zyloprim hong kong cheapest buy alli tablets weight loss acquisto keppra sicuro online prednisone 5mg tablets picture where to buy permethrin cialis sublingual sale online pharmacy arjuna indian herb celexa on line depo provera reviews 2012 yasmin canada prescription elavil generic buy motrin cheap buy tretinoin 0,025 online india ditropan online legally atlantic drugs coupon code voveran sr dosage recommended canadian drugs legal usa the chepest keftab atrovent uk online trandate online in us where to purchase lithium motilium 10mg tab doxycycl hyc cap 100mg acne bactrim usa can you order zyrtec allergy relief risperdal 4 mg price canadian online pharmacy fast delivery discount singulair coupon erection packs 2 by mail we heart it app ampicillin drugs interact with avoid order generic noroxin quickest silagra metronidazole flagyl dosage for trichomoniasis viagra canada drug store coreg how to buy atarax medication ingredients cost of prilosec 40 mg effexor xr dosage too high side effects of long term use of aleve can you get phenergan buy generic neurontin does allopurinol cause gout flare buy mentats fallout 3 aldactone prescription coupon buy arimidex online canada no prescription revia low dose birth control alli uk brand name provera tablets online mercedes ci cipro 55 sale safe place order metformin phenergan for kids travelling healthy blood pressure 50 year old male tamoxifen and weight gain uk existe el viagra para mujer allopurinol dosage renal cheap mobicam baby monitor wireless buy generic silagra with bonus seroquel in the uk now buy ciplox online amazon atrovent inhaler discontinued femcare next day delivery carafate no prescription canada can you only get amaryl on prescription pravachol buy online ireland buy diclofenac gel online overnight beconase aq visa generic zithromax usa pharmacy cold medicine for coumadin users voltaren manufacturer basel azulfidine dosage rheumatoid arthritis buy ashwagandha canada erexin-v suppositories buy didronel online usa probalan side effects long term use doxycycline hyclate uses current price cafergot como se usa benzac wash buy lustral 50mg buy differin new zealand online costco uk online store cheap doxycycline 20mg how many pills in a medrol dose pack erectile dysfunction treatment without drugs prednisone for dogs with cancer what is femara for infertility cabgolin cost comparison what is like metformin but over the counter buy propecia next day what does provera treat what is glyset lamisil cream in india is generic inderal effective reviews on acai berry diet diovan online generic highest strength cialis is there a generic for trazodone dutas 40 mg dose deltasone phone orders ciprofloxacin ear drops cost levitra plus generico italiano non persciption accutane propranolol now co uk forum online without cheap zaditor buy cabgolin boots buy brand viagra online overnight losec mups omeprazole when will a generic version of viagra be available buy aciclovir tablets over the counter post cycle therapy brahmi order revia 50 mg tenormin where can i buy it safe zenegra no prescription tadalafil from usa what is the correct dosage of cytoxan canine doxycycline dose viagra generic paypal discount buy generic antabuse with bonus snovitra super power online forum where can i get the acai berry from nolvadex dosage for women ortho tri cyclen lo generic name 2011 sale generic viagra zenegra pfizer what is green tea extract with hoodia remedio sertralina vipps pharmacy canada discount cardizem sending prescription medication mexico comprar levlen original en madrid is there a drug comparative to diltiazem alli pill availability lexapro discount card activation pet meds canada pharmacy are propecia and finpecia same buy propecia finasteride 1mg what is ceftin antibiotic used for prilosec reviews side effects treating imiquimod side effects tricare mail order pharmacy registration and prescription form dipyridamole 100mg buy lamisil online india generic drug ponstel viagra tabs. uk reglan on the internet albuterol atrovent nebulizer treatment dose dog medicine online canada heartgard ranitidine delivery london how much do coreg leads cost side effects of zocor 80 mg comprar lopid pela internet can you get promethazine over counter how to get free viagra canadian can you prescription buy lopressor mg without cheap prescription reglan can you get clomiphene on the nhs purchase valtrex canada allopurinol medication side effects warnings nexium 10 mg plicuri pret minocycline reviews yahoo current price wellbutrin sr buy clonidine us albendazole with prescription side effects of promethazine hydrochloride tablets procardia xl max dose erexor order canada nolvadex canada prescription citalopram hydrobromide missed dose vytorin sales 2005 synthroid over the couter diovan hct prescription discount card dipyridamole no prrescription promethazine hcl 25 mg otc drug sales data can i make brafix minipress over counter mail order generic eulexin best feldene prices safe propecia no prescription abilify online uk brand name diclofenac gel online ordering elavil here in canada oracea side effects doxycycline where can i get alphagan from what is silagra 100 cheap adalat cod overnight levitra sale drugstore lowest ibuprofen dosage 200 mg buy generic tetracycline online low cost no prescription store amantadine online aygestin in usa where to buy lexapro online mexico celexa shortage 2012 do i need a prescription for xalatan why is pradaxa better than coumadin acheter xenical orlistat en ligne nitrofurantoin monohydrate macrocrystals 100 mg side effects generic name for haldol where to purchase voltaren us online pharmacy no prescription lozol meds net neurontin generic tadapox pas cher what are the side effects of clonidine in children azithromycin tablets 250mg price valtrex dosage brand cialis side effects uk imuran sublingual dosage generic tadalis sx in usa viagra sublingual over the counter usa renagel no prescription needed nizagara over counter metformin 1000 mg online no prescription permethrin cream rinse 1 side effects of roxithromycin 150mg admiral insurance jobs beconase aq canada overnight delivery no prescription look buy amantadine online what is female cialis for buy brand viagra australia pet meds online review long term side effects of methotrexate injections zovirax online no prescription medrol 4mg tab kamagra gold on line costco pharmacy femcare price xenical bonus pills genuine dramamine best price generic fertomid cost can i cut wellbutrin tablets in half top 10 online abana sites awc canadian pharmacy scam behavioral side effects of flonase in children pharmacies alesse prescription overnight pfizer wins viagra patent trial can you buy cialis jelly in ireland 20mg we buy any car wiki pharmacy mexico levitra cephalexin side effects uk what is advair hfa current price innopran xl 1 800 numbers for viagra cvs drugstore wiki what is lithium used for yahoo answers celebrex prices comparisons yasmin free shipping cheap topamax 100mg can you get high off crestor lasuna online forum dulcolax refills diflucan dose for yeast infection in children side effects of acyclovir 800 mg tablets ketoconazole cream hair loss cialis soft prices cvs orlistat generic price fluoxetine delivery tantra sildenafil oral jelly hyzaar wikipedia ordering low dose levitra super active genuine minocycline 100mg geriforte doctors online advair diskus 100/50 mcg amsa fast orlistat reviews viagra for women for sale uk unisom side effects uk zyvox linezolid generic why is there a shortage of premarin is cytotec over the counter order painkillers no prescription amoxicillin without prescriptions is there a drug comparative to digoxin femara reviews fertility how much does lithium cost per pound rx list pravachol ramipril hydrochlorothiazide canada estrace online store how long does metformin xr take to work wsj generic lipitor goes on sale this week remedio cipro xr 1000 xenical pharmacy order comprar forzest portugal elocon us companies only does remeron cause weight loss original kamagra oral jelly online where can i buy cytotec here in philippines kamagra without rx discount nolvadex of canada mentat wiki how much is permethrin cream in the philippines what does cialis mean nizoral anti dandruff reviews saw palmetto no prescription compare prices getting cardizem in australia where do your inject toradol very cheap requip online parlodel purchase wellbutrin xl and cough medicine canadian pharmacy cialis 20 mg buy crestor pills tegretol online in usa generic pletal usa pharmacy l-tryptophan where can i buy it digoxin pill canadian levitra cialis viagra comparison or levitra is rogaine 5 available over the counter is 20mg of prednisone considered to be a high dose neurontin order in the us buy lamisil no prescription fast delivery can you buy lukol online buy levlen discount cheap atarax overnight order calanthe better than benicar bupropion spain cialis super active mg buy revia precio mexico tinidazole online bestellen generic from retin-a ge lisinopril online bestellen hydrea medication uses premarin for sale australia purchase zyban pills haldol shop net blopress new zealand can you buy zebeta online cheap prescription lamisil prescription drug nymphomax tablets from buy generic propecia canada 5mg canada buy ditropan without prescription amoxil prices at costco acheter pas cher premarin cialis dosage forum buy lanoxin perth australia legal buy nitrofurantoin online canada side effects of clonidine patch legal buy brand advair diskus online canada diclofenac gel 10 mg cost do you need rx olanzapine canada cheap buy effexor xr order protonix tablets maximum dose coversyl discount code for allopurinol buy meloxicam for dogs online australia missed avapro dose how to use doxycycline hyclate 100mg lov cost zyban prandin 5mg tablets fastest reminyl uk delivery flagyl er shelf life prandin in the uk now hytrin dosage buy diclofenac 50mg online alesse for men sale in uk buy evista online canada no prescription seroquel buy canada buy antibiotics online no prescription uk delivery lowest priced micronase doxycycline hyclate 50 mg for rosacea pet rx canada cheap kamagra oral jelly online erythromycin 250mg tablets used what is terramycin used for in dogs indian atorlip pharmacy glucophage medication used non prescription acticin order medications without prescriptions styplon lawsuit canada is lipitor sold over the counter can buy synthroid online doxycycline hyclate 100 mg capsules suhagra 50 mg review levitra 10 mg schmelztabletten vardenafil retin a reviews makeupalley super active viagra reviews is lamictal better than lamotrigine zyrtec rx otc switch how to use benzac ac paroxetine woldwide shipping snovitra super power ships from india cheap minocycline acne cialis soft noprescrition needed uk online pharmacy mail order live turkeys nexium dosage for infants ver un rey en la habana online baclofen prices usa buy levitra mg albendazole perth australia side effects of high blood pressure medication lisinopril duphalac over counter uk buying clomid for dogs can you take brahmi daily amoxil 500 mg cost generic zaditor eye drops comprar atarax en argentina amoxil online india lioresal price india mechanism of action of tetracycline on e.coli mail order tetracycline online amitriptyline migraine children what is zithromax drugs how to buy lincocin in london plavix 75 mg online pharmacy has best price dramamine diclofenac ratiopharm gel 100 g n2 can get reglan over counter azulfidine for dogs buy ralista to buy in england best over the counter ed pills buy tenormin online worldwide pharmacy aciphex celebrex dosage recommendations closest over the counter drug to viagra viagra soft without a perscription prilosec coupons march 2011 buy birth control online no prescription us order decadron online uk omifin dosis hombres billig actoplus met online kaufen diflucan cheap us pharmacy indian generics online lincocin baclofen uses side effects how to purchase colospa online can you take brand advair diskus daily purches of cipro without a prescription como comprar glycomet buy eulexin boots pharmacy revista veja on line doxycycline over the counter in india buy doxycycline 200 mg how to buy abilify viagra jelly without prescription miami bactrim forte dosis pediatrica canada online buy effexor xr avapro online pay paypal chlamydia symptoms mouth pictures over the counter diakof buying pletal in manchester lisinopril noprescrition needed canada online pharmacy zovirax fast mexico buy cheap singulair using pay pal propranolol without prescriptions


Apprenez à jardiner dans le respect de votre environnement, un site de la SNHF

Agapanthus 'Blue Heaven' (La plante du mois)

Jardine avec Bottine et ses amis. de 3 à 11 ans

Améliorations variétales au bénéfice des consommateurs

jury label rouge dahlia 2008 (C Secq)Chaque année dans le secteur horticole, de nouvelles variétés, voire de nouvelles espèces, sont proposées à la vente. Variations de port, de couleur, de goût, de précocité, sont les caractéristiques les plus visibles pour le consommateur. Tout aussi importantes sont les tolérances à des maladies, à des insectes, à des stress environnementaux : sécheresse, salinité…
L’objet de cet article n’est pas de présenter les méthodes employées par les sélectionneurs, mais de tenter d’expliquer les causes et les conséquences de cet enrichissement permanent du patrimoine variétal.

De l’introduction raisonnée à la création variétale
L’horticulture ornementale a toujours cherché à diversifier son offre en introduisant des espèces venant d’autres pays ou continents. Il est d’ailleurs fort intéressant de retracer l’histoire de ces introductions, dont la période forte est celle des grandes découvertes, du temps de Christophe Colomb, et qui se poursuit de nos jours : il suffit de prendre pour exemple la famille des protéacées… L’introduction, et surtout l’introduction raisonnée, comme celle qui voit le jour actuellement, est un travail de domestication. Il s’agit de rechercher quelles espèces s’adaptent à nos climats, d’étudier leur comportement sous différents environnements, de rechercher leur adaptabilité éventuelle à la culture en conteneurs. À ce stade, en général, la variabilité génétique au sein de l’espèce est peu prise en compte, le choix des individus retenus est fait sur la base des caractéristiques phénotypiques d’apparence, d’allure, de port ou de croissance. Vient ensuite une mise au point des méthodes de propagation en recherchant des taux de multiplication élevés, et pour cela, toutes les méthodes habituelles des pépiniéristes sont mises en oeuvre. La décision de commercialiser n’interviendra que si ces étapes sont franchies avec succès. Aujourd’hui, et dans le cadre du raisonnement sur l’agriculture durable, de nouveaux critères sont de plus en plus fréquemment pris en compte, avant d’introduire et de diffuser de nouvelles espèces. Une attention particulière peut être apportée à de faibles exigences en eau dans les régions méditerranéennes. Tel est le cas à la Villa Thuret, jardin botanique situé sur le cap d’Antibes, où toute espèce candidate à l’introduction reçoit en tout et pour tout un arrosage l’année de son implantation. Le caractère potentiellement invasif de la nouvelle espèce doit être apprécié avec soin.

Les raisons sont multiples :
- la concurrence entre espèces risquerait d’éliminer des espèces endémiques,
- le développement incontrôlé de semis risquerait de modifier les paysages,
- les espèces introduites sont souvent peu sensibles aux parasites et aux prédateurs ; si leur développement est important, il n’y aura pas de régulation biologique. En contrepartie, cette faible sensibilité aux parasites est un atout, au moins temporaire, des plantes nouvellement introduites et domestiquées car certains d’entre eux peuvent s’adapter à un nouvel hôte. La phase suivante de cette domestication est l’exploration de la variabilité génétique au sein de l’espèce pour développer par hybridation des formes nouvelles différentes des plantes parentales, qui seront ensuite choisies, multipliées et proposées à la vente. De nos jours, les introductions concernent essentiellement les espèces arbustives ou buissonnantes, certaines potées fleuries à multiplication végétative. Néanmoins l’enrichissement du nombre de variétés provient essentiellement de nouvelles créations génétiques.

La suite de cet article est réservée à nos membres adhérents. Rejoignez-nous et découvrez les avantages qui vous sont réservés.

Lire la suite...

Yvette Dattée
Présidente du conseil scientifique de la SNHF
Jardins de France Novembre 2009

Si cet article vous a plu

Abonnez-vous à Jardins de France...

acheter les actes du colloque Quand les plantes se parlent