Introduction to On-farm Organic Plant to On-farm Organic Plant Breeding Introduction to On-farm Organic Plant Breeding Organic Seed Alliance ... The principles of

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  • Introduction to On-farm Organic Plant Breeding www.seedalliance.org

    Introduction to On-farmOrganic Plant Breeding

    Organic Seed AllianceAdvancing the ethical development and stewardship of the genetic resources of agricultural seedPO Box 772, Port Townsend, WA 98368

    This publication was made possible through a grant from Organic Farming Research Foundation and Seed Matters

  • Introduction to On-farm Organic Plant Breeding www.seedalliance.org2

    Section I: Introduction...................................................................................................................................................3 Whyplantbreedingisimportant......................................................................................................................................3 Aphilosophyoforganicplantbreeding.........................................................................................................................4 Ourfarmingancestorsneverstoppedbreeding...........................................................................................4 Returningfarmerstotheirroleasseedstewards........................................................................................4

    Section II: Plant breeding basics...............................................................................................................................5 Selectionintheoryandpractice........................................................................................................................................5 Howtoselect..............................................................................................................................................................................8 Acropsmatingsystemandhowitaffectsplantbreeding.....................................................................................8 Self-pollinatedcrops................................................................................................................................................9 Cross-pollinatedcrops............................................................................................................................................9 Breedingself-pollinatedcropsvs.breedingcross-pollinatedcrops..................................................................9

    Section III: Developing a plant breeding plan.....................................................................................................12 Thinkingaboutyourtargetenvironment...................................................................................................................12 Determiningtraits.................................................................................................................................................................13 Prioritizingtraits...................................................................................................................................................................13 Howcanthetraitsbemeasured?.....................................................................................................................13 Howeasilycanthetraitsbeinherited?.........................................................................................................14 Choosingparents...................................................................................................................................................................13 Creatingabreedingtimeline............................................................................................................................................15

    Section IV: Theories of field-based organic plant breeding...........................................................................21 Howgenestravelfromparentstooffspring..............................................................................................................21 Howgenesdeterminetheappearanceandperformanceofplants..................................................21 Howgenestraveltogetherduringreproduction......................................................................................22 Howgenesoperateinpopulations................................................................................................................................24 Howtoseethegeneticdifferencesbetweenplants...............................................................................................28 Understandtheeffectsoftheenvironment.................................................................................................28 Ensurethatplantsreceiveconsistenttreatment.......................................................................................29 Usesufficientpopulationandplotsizes.......................................................................................................29

    Section V: Examples of farmers breeding for organic systems......................................................................30 AbundantBloomsdaleorganicspinachbreedingproject...................................................................................30 Whatwerethegoalsofthisproject?..............................................................................................................30 Breedingprocedure...............................................................................................................................................30 WinterSproutingBroccoli...............................................................................................................................................31 Whatwerethegoalsofthisproject?..............................................................................................................31 BreedingProcedure...............................................................................................................................................31

    Glossary and index.......................................................................................................................................................33

    References and resources..........................................................................................................................................36

    Table of Contents

  • Introduction to On-farm Organic Plant Breeding www.seedalliance.org3

    Why plant breeding is importantThehistoryofthedomesticationofourcropplantsisalsothehistoryofplantbreeding.Throughmanygenerationsoflaborioushumanselection,wildplantsbecameusableasagriculturalcrops.

    Ourhunter-gathererancestorshadtohaveanintimaterelationshipwithplantstonoticethegeneticvariationthatexistedandcontinuallyaroseinordertomakemeaningfulprogressinthedo-mesticationprocess.Thisisoneofthefundamentalpreceptsofplantbreedingandgivestheseearlyinnovatorsfullstatusasplantbreeders.

    Coupledwithearlyhumanselectionwasastrongelementofnatural selection.Alloftheancestorstoourmoderncropspeciesweregrownwithoutsup-plementalnutrition,fertility,orpestprotectants,andwereconstantlyexposedtothechallengesoftheenvironment.Thebestofthefarmer-breed-ersspedthisprocessalongbyselectingfromthemostdesirableplantsfortheirfoodandfibervalue,usingtheseastheparentalstocksforsubsequentgenerations.Thisbalancebetweenhumanandnaturalselectionpersisteduntilthebeginningoftheindustrialagriculturaleraofthe20thcentury.

    Allagriculturalcropshavecontinuouslychangedwiththeselectionpressuresappliedfrombothfarmersandtheenvironmentsinwhichtheywerecultivated.Whenfarmersandtheenvironmentchanged,thecropchanged.Manyofourcropscon-tinuetochangeandadapttonewchallenges.

    Thenumberofenvironmentsthatcropsarebredin,andthenumberofbreeders,havebothshrunkoverthepast100years.Thisisbecausefarmersinmostagriculturalregionsoftheglobedolittleornoplantbreedinganymore,andthenumberofre-gionalizedseedcompaniesdoingbreedinghasalsodrasticallyshrunkinthepast40to60years.

    Withtheadventoftheindustrialagriculturalmodeltherehasbeenanarrowingofthesetoftraitsthatareconsideredcriticaltotheproductionofmostmoderncrops.Theindustrialmodelhasalsoled

    toagradualspecializationshiftinwhereandhowmanyofthemosteconomicallyimportantcropsaregrown.Inthepre-industrialagriculturalera,almostallcropswerespreadacrossmanyenvironmentalandgeographicnichestosatisfythediversityofagriculturalsettlements.Thismeantthattheywereconstantlyadaptingtoadiversityofclimaticcondi-tionsandtheever-changingneedsofthehumanag-riculturalsocietiesthatwereusingthesecrops.Thefarmersineachregionwerethebreeders.Somefarmerswereundoubtedlybetterbreedersthanothers.Therehasalwaysbeensomespecializationinmanyaspectsofagriculturalsocieties,butinthispre-industrialera,everyagriculturalcommunitycertainlyhadtheseedneededbythatcommunity.Seedofeachofthesecommunityvarietiesweregeneticallyuniquefromasimilarvarietyofthesamecropinthenextcommunity.Thispatchworkofuniquevarietiesisthenmultipliedthousandsoftimesacrosstheuniqueenvironmentsofagricul-turalcommunitiesaroundtheglobe.

    Cropgeneticdiversityinthepre-industrialerawasalsomuchgreaterthanwhatcurrentlyexistsinmodernagriculturebecausethediversitywithineachcommunityvarietywasfarricher.Farmersdidnotdemandthekindoftraituniformitythatisnowthenorminourmoderncrops.Thisallelic*di-versitywaspartofeverycroppopulationandwasreflectedbymanyuniquegenotypes(andpheno-types)ineachfield.

    TherewasagreatblossomingofseedcompaniesinNorthAmericaandEuropeinthesecondhalfofthe19thcentury.Withtheadventofseedasacommercialcommodity,andtheemergenceofseedcompanies,therewasanincentivetoproduceseedofcropvarietiesthatweremuchmoreuniformandpredictable.Theseearlyseedcompanieswereregionalinnature.Theyreliedonacentralstoreinametropolitancenterandsupplementedwithmailordersformuchoftheirbusiness.

    Theindustrializationofagricultureinthe20thcenturyledtoamuchhigherdegreeofspecializa-tion.Specificregionswithmoreidealclimatesforacertaincroptypeandprimeagriculturallandbe-c