Establishment and registration of seed orchards.

ODC 232.3

FOLIA FORESTALIA _tg

lETSANTUTKIMUSLAITOS ^• INSTITUTUM FORES-TALE FENNIAE ^• HELSINKI 1970

RISTO SARVAS

ESTABLISHMENT AND REGISTRATION OF

SEED ORCHARDS

N:ot I—lB _on lueteltu Folia Forestalia-sarjan julkaisuissa ^I—4l.

Nos. I—lB _are listed inpublications ^I—4l of the FoliaForestaliaseries.

1966 No 19 Paavo Tiihonen: Puutavaralajitaulukot. ^{1. Maan} etelapuoliskon manty ja kuusi. 2.—

No20 Seppo ^Gronlund ja Juhani^Kurikka: Markkinapuun alueittaiset hankintamaaratvuosini 1962 ja ^1964. LopuUiset ^tulokset.

Removalsofcommercial roundwoodinFinland by districts in 1962and 1964. Finalresults. 4, No 21 KullervoKuusela: Alandsskogar ^{1963—64. 2,—}

No22 Eero Paavilainen: Havaintoja kasvuturpeen kaytosta mannyn istutuksessa.

Observations onthe use of garden_peat ⁱⁿ Scots pine planting. ^1,—

No23 Veikko O. Makinen: Metsikon runkoluku keskilapimitan ^funktiona pohjapinta-alan yksikkoa ^kohti.

Number of stems ina stand asfunctionof the meanbreast height ^diameterperunityof basal area. 1,^—

No24 PenttiKoivisto: Ita- ja Pohjois-Hameen koivuvarat.

Birchresources in the Forestry ^{BoardDistricts of Ita-Hameand} Pohjois-Hame. 1,^— No25 Seppo Ervasti — Terho Huttunen: Suomen puunkaytto vuonna 1964 ja ^{vuoden 1965}

ennakkotiedot.

Woodutilizationin Finlandin 1964 and preliminary data for the _year 1965. 3,^— No26 Sampsa ^{Sivonenja MattiUusitalo: Puun} kasvatuksen kulut hakkuuvuonna 1965/66.

Expenses ^{of timber} production ^{in Finlandin the} cutting season 1965/66. 2,^— No27 Kullervo Kuusela: Helsingin, Lounais-Suomen, Satakunnan, Uudenmaan-Hameen,Pohjois-

Hameen ja Ita-Hameenmetsavarat vuosina 1964—65.

Forest resources in the Forestry ^{Board Districtsof} Helsinki, Lounais-Suomi, ^Satakunta, Uusimaa-Hame, Pohjois-Hame and Ita-Hame in 1964—65. 3,^—

1967 No28 Eero Reinius: Valtakunnanmetsien V inventoinnintuloksianeljan Etela-Suomenmetsan hoitolautakunnansoista ja metsaojitusalueista.

Resultsof thefifth nationalforest inventory concerning^the swamps and forest drainage

areas of four Forestry ^Board Districts in southern Finland. 3,^—

No29 Seppo ^{Ervasti, Esko Salo} ja ^{Pekka Tiilila:} Kiinteistojen raakapuun kayton ^tutkimusvuo

sina 1964—66.

Real estates ^raw woodutilization_survey inFinland in 1964—66. 2,—

No30 Sulo Vaananen: Yksityismetsien kantohinnat hakkuuvuonna 1965/66.

Stumpageprices in private ^forests during ^the cutting ^season 1965/66. 1,^— No31 Eero Paavilainen: Lannoituksen vaikutusramemannikon juurisuhteisiin.

Theeffect of fertilizationonthe root systems of _swamp pine stands. 2.—

No 32 Metsatilastoa. I Metsavaranto.

Foreststatistics of Finland.I Forest resources. 3,^—

No33 Seppo Ervasti ja Esko Salo: Kiinteistoilla lammonkehittamiseen kaytetyt polttoaineet

v. 1965.

Fuels usedby ^real estates for the generation^{of heat in 1965.} 2,^— No34 VeikkoO. Makinen:Viljelykuusikoiden kasvu- ja rakennetunnuksia.

Growth and structure characteristics of cultivated _spruce stands. 2,—

No35 Seppo ^{Ervasti—Terho Huttunen: Suomen} puunkaytto ^{vuonna 1965 ja} ennakkotietoja vuodelta 1966.

Wood utilizationinFinlandin 1965 and preliminarydata for the _year 1966. 4,^— No36 Eero Paavilainen— Kyosti Virrankoski: Tutkimuksia veden kapillaarisesta ^{noususta tur}

peessa.

Studieson the capillary ^rise of water in

peat. 1,50

No37 MattiHeikinheimo—Heikki Veijalainen: Kiinteistojen polttoainevarastot talvella1965/66.

Fuelstocks of real _estates inFinland in winter 1965/66. 2,^—

1968 No38 L. Runeberg: Forhallandet mellan driftsoverskott och beskattad inkomst vid skogs beskattningen ^{i Finland.}

Therelationship^between surplus ^{and taxableincome inforesttaxation in Finland.} 2,^— No39 MattiUusitalo:Puun kasvatuksenkulut hakkuuvuonna 1966/67.

Costs of timber production ⁱⁿ Finland during the cutting ^season 1966/67. 2, ^— No40 Jorma ^{Sainio—Pentti Sorrola: Eri} polttoaineet teollisuudenlammon ja voiman seka

kiinteistojen lammonkehittamisessa_vuonna 1965.

Different fuels in the generationof industrial heat and

power and in thegeneration^of heat by ^real estates in 1965. 2,—

No41 Pentti Rikkonen: Havupaperipuidenkuorimishavio VK-16 koneella kuorittaessa.

Thebarking loss of coniferous pulpwood ^{barked with VK-16 machines.} 2,^—

No42Kullervo Kuusela ja ^{Alii Salovaara:} Etela-Savon,Etela-Karjalan, Ita-Savon, Pohjois-Karja lan,Pohjois-Savonja Keski-Suomenmetsavarat vuosina 1966—67.

Forest _resources in theForestry ^{Board Districtsof} E-Sa,E-Ka,I-Sa,P-Ka, P-Sa and K-S in 1966—67. 3,—

No43 Eero Paavilainen:Vanhojen ramemantyjenkasvun elpyminen lannoituksen vaikutuksesta.

On the

response ^to fertilizationof old pine trees growing ^onpine swamps. 2,^— No44Lalli Lame: Kuplamorsky, (Rhizina ^undulataFr.), ^{uusi metsan tuhosieni maassamme.}

RhizinaundulataFr., ^anew forest disease in Finland. 1,^—

Luettelo jatkuu ^3. kansisivulla

FOLIA FORESTALIA 89

Metsantutkimuslaitos, InstitutumForestaleFenniae.Helsinki1970

Risto Sarvas

ESTABLISHMENT AND REGISTRATION OF SEED ORCHARDS

PREFACE

The following instructions concerning ^the establishment ofseedorchards _were completed gradually ^{onthebasisofresultsof} investigations carried _outover anumberof

years. They were firstissued inthe Finnish language ^anddistrib uted _{among persons} engaged ^{in tree} breeding in this

country ^{in 1968.} English language instructions were dublicatedin1970 and they

were for the main

part ^{similar to those con} tained in the Finnish language ^{issue. The} instructions given ^{below have been} slightly revised.

The main purpose of ^these instructions is to drawattention_tothe _manydifferentfactors

to be considered inconnectionwith the ^estab lishment of seed orchards. They are also in

tended _to illustrate that_most ofthe problems arising ^{in this} connection, ^{andwhich as late}as some10 years ago had to be settled by using the rule of thumb, can ^nowbe solved onthe basisof investigatory ^data.

The authortakes this opportunity ^{to thank} his _numerousfellowworkers whotook

part ⁱⁿ the investigations ^involved. Special ^{thanks are} due _to Mr. Olavi Helenius, Forest Officer, ^and Mr. Jaakko ^{RokkonenandMr. Veikko} Silander, Forest Technicians, ^and Mr. Pauli Vartinen, who led and supervised ^thevery exacting field work.

The manuscript was read by ^{Mr. Veikko} Koski, Dr. Ph. His valuableadvice receiveddue consideration.

Helsinki, October 12,1970 Risto Sarvas

13121—70/80

TABLE OF CONTENTS

PREFACE 1

INTRODUCTION 3

SEED ORCHARD TYPES 4

GUALITY CLASSIFICATION OF SEED ORCHARDS 5

PHENOTYPIC SEED ORCHARDS 6

Clones 6

Topophysis ^and Cyclophysis ⁷

Physiology ^of Flowering ⁷

Geographical ^{LocationofSeedOrchards 12}

Location ofSeed Orchards 15

Clone StructureofSeedOrchards 17

SEED ORCHARD'S UTILIZATION AREA 17

CARE OF SEED ORCHARDS 18

MEASUREMENTS TO BE MADE IN SEED ORCHARDS 19

REGISTRATION OF SEED ORCHARDS 21

LITERATURE 23

INTRODUCTION

The term seed orchard refers to a stand establishedfor^the production ^{ofseed.Itshould} perhaps ^beadded: especially ^forthe production of large quantities ^{of seeds. The} concept of seed orchard should be confined _to

open pollinated ^{stands. For the sake of} clarity, artificially pollinated ^{stands should be termed}

"plus ^tree collections" or "special ^{tree collec} tions". When undertaking ^the establishment of _a seed orchard, ^{it shouldbebornein mind} thatthe seedto be produced ^is expected ^tobe genetically ^and physiologically good, oratleast better than

average stand-produced ^seed.The production ^{of a} heavy ^{seed crop of} high genetic ^and physiological ^{standard is the} pri mary objective ^{of seed orchards.} In addition, the orchards, as a rule, renderservicestotree

breeders in the work they ^do to increase the improvement degree. ^{Production of seed in} stands planted ^{for this} purpose only ^has long been practised ⁱⁿ farming. ^{The ideahasthus}

existed for so long ^{that it is} relatively ^un important ^{who it} was thatfirst suggested ^itin forestry. ^{It is} perhaps ^more important ^to give credit _to the researchers who first began ^to apply ^{it on a} fairly large ^{scale in} forestry.

Mention should be made especially ^of Syrach Larsen who in his dissertation (1934) pointed

out the special possibilities ^offered by ^theuse of grafts ^{for the} production ^of racially high standard seeds, ^and Holger ^Jensen (1943) ^and Bertel Lindquist (1948) ^who developed ^the methods further.

Inthis ^{connectionitis} appropriate ^to point

outthatin practical silviculture, ^for reasons of economy, it is difficult to meet evenmodest requirements ⁱⁿ respect ^{of the racial} quality of the ^seed tobe usedin reforestation. ^This is duetothe factthatitisalmost always necessary to collectthiskindofseedfrom standing ^trees.

This hasbeenthebitter experience ^{in Finland} in the last ^few _years. It is, therefore, ^obvious that_even though no greater genetic ^demandis made on the seed than that it originates ^from

a good ^{tree in a} racially good stand, ^the establishment of seed orchards is well warranted

in order torationalize the collection ofseed of this quality.

Fig. ^{1.Seedorchard} programinFinland.Situa tionin the autumn of 1969.

The need for thfe establishment of seed orchards is felt especially strongly ^{in forest} districts such as thewholeofnorthern Finland, where, on account of the cold climate, ^the seed does _notmature regularly. By establishing, in _warmer climates, ^{seed orchards} designed ^to

serve theseareasitis possible ^{to ensureannual} maturation of the seed.

As a rule, ^{the seed} produced by ^a given ^seed orchardcanbeused successfully only ^inacertain geographical ^{area that canbe marked out on} the map. This _area is called "the utilization

area of ^theseed orchard".

Onthebasis ofthe principles applied ^inthe attempts ^{to meet the} objectives ^{set for seed} orchards, ^{these orchards can be} grouped ^into different types ^{of structure.} Thus, ^{two main} groups ^can immediately ^be distinguished: ^1.

Graft orchardsand 2. Seedling ^{orchards. These} main groups ^can further be dividedinto sub

groups. Besides this type-grouping, ^aclassifica tion system ^canbe employed. ^Thepurposeof this system ^{is to} classify ^{the orchards} on the basis ofthe genetic quality ^oftheseed produced by ^them. Below, ^the type-grouping ^and quality classification ^will be dealt with in a more

detailed way.

SEED ORCHARD TYPES

In practical ^tree breeding, ^the significant seedorchard types can preliminary ^be grouped, forinstance,asfollows:

A.Graft orchards (synonym: ^clone orchards)

a. Phenotypic graft ^{orchards.Thetreeshave} mainly ^{been selected on the basis of} phenotype. ^The general principle ^ofbreed ing ^is usually ^{massselection.}

b. Genotypic graft ^{orchards. Thechoice of}

trees essentially depends, ^inadditionto phenotype, ^{onthedataobtainedon}geno type.The general principle ^oftreebreed ing ^is usually family ^selection.

B. Seedling ^orchards

a. Thetreesinthe seedling ^orchard originate fromopen pollination.

b. The_treesinthe seedling ^orchard originate from controlled crosses between pheno typic plus-trees.

c. Progeny ^{test seed orchards. The} starting point ^{can be a seed} produced by open pollination or by ^controlledcrosses. The orchard should be established in such a

way that at first it puts ^into effect the principles ^oftheprogeny^testbut later, ^as

aresult of thinning, changes ^to serve, ^to an increasing degree, ^theseed production,

In this ^{briefdiscourse} itis not possible ^to penetrate ^{into the details ofall the} different types of^{seedorchardsmentioned} above, ^orto weigh ^the advantages ^and disadvantages ^ofthe various seed orchards _types. The seed orchard program, which is about_to materializeinFin land, ^{is for the time} being ^almost exclusively based ona graft ^{orchard of the} type ^which gradually changes ^{from a} pheno- to ^a genotypic orchard; therefore, ^{in the} following pages^most attention is paid ^{to this} type. ^In additionit mustbe kept ^{in mindthat Pinus} sylvestris ^seed

orchardsconstitutethemainpartoftheFinnish seed orchard_program.

Theinitial_costof_a graft ^{orchardisconsider} ably higher ^thanthatofa seedling ^orchard.To counterbalance this, ^the graft ^{orchards afford} certain significant advantages. ^{Above all the} genotype of the trees remains unchanged ⁱⁿ propagation. ^Also graft ^{orchards can beestab} lished irrespective ^{of the trees'} genetic ^inclina tion for flowering. Many ^ofthebest plus ^trees flower _so seldom and scantily ^{that efforts to} obtain adequate ^{amounts of seed for the} establishment of seedling ^{orchards are met} with considerable, ^ifnotalmost insurmountable, difficulties, especially ^ifthe seedling ^orchardis established from seed produced by ^{means of} controlled crossings. ^Thisis particularly ^trueof the plus trees of northernFinland. It

appears, therefore, ^that seedling ^orchards designed ^to

serve northernFinlandcan only ^be established

at the

expenseofthe effectiveness ofselection (selection differential, ^{cf.alsoGustafsson1950,} p. 118). ^{Inthis connectionit shouldbe} pointed

out that

poor genetic inclinationfor flowering,

as such, ^{is no} insurmountable obstacle in forest _tree breeding. By grafting ^the plus ^trees which flower scantily ^{intheir naturalhabitat} and by transferring ^the grafts ^to grow in a warmer climate, flowering can usually ^{be im} proved sufficiently ^{to reacha} satisfactory ^level.

The line between the phenotypic ^andgeno typic graft ^{orchards is} gradual ^{rather than}

clear-cut. ^The genotypic information ^forest

tree breeders seek _to obtain _can in the first place ^{bedividedintotwo}groups:

1. Information_onthe heritability ^ofcertain phenotypic ^traits, important ^{from the forest} economy point ^of view, ^{such as} height ^and diameter growth, branchiness, percentage ^of

summer wood, ^{andthe annual} developmental cycle, ^and

2. Information onthe general ^and special combining ability ^{ofthe treesusedfor} breeding.

The forest genetic ^{researchwork done}so far has proved ^{that the} heritability ^ofcertain pheno typic ^traits important ^{from the} breeding point of view is generally high (for example, ^the heritability ^oftheannual developmental cycle).

The phenotypic observationsmadeinrespectof this kind of traits accordingly provide ^far reaching information_on

genotype.^So far, ^how

ever, the heritability ^{of several of those traits} which are most important ^{from the} breeding point ^of view, ^{such as} growth, ^has proved ^tobe low. Therefore, ^{at least forthe time} being, ^the only possible way ^to obtain information _on this subject ^isto clarify ^the general ^and specific combining ability of the selected trees. It is,

however, ^{reasonable to} emphasize ^that our notion of phenotype ^{is, so} far, very vague. ^It seems that by increasing ^{the number of the} phenotypic ^{traits tobe studiedand} by splitting collective traits, ^{such as} growth, ^{into an in} creasing ^numberofcomponents,^{morerestricted} physiologically, ^itis possible ^{toobtainaclearer} notionof phenotype. ^{It is also reasonableto} anticipate ^thatthis procedure ^enables important phenotype ^{traitswithlow} heritability ^tobe split into componentswith considerably higher ^her itability. ^Themore far-reaching ^theconclusions drawn_onthebasis of phenotype ^fromthe_geno type ^{ofthe trees}usedfor breeding, ^the lighter willbe the ^loadonprogeny^tests.Theload^will inany casebe

very heavy.

QUALITY CLASSIFICATION OF SEED ORCHARDS

Themain

purpose ofthe registration ^ofseed orchards isto ascertain to whatextent aseed orchard reported ^for registration meets the objectives generally prescribed ^{for seed or} chards, ^with regard ^{to the} genetic ^and phys iological ^{standard of the seed} produced by them. ^This applies particularly ^{to the} genetic quality ^ofthe seed, because, as ^a rule, ^{it isnot} possible to drawconclusions aboutthis _onthe basis ofthe fenotypic parameters ^oftheseed.

Of the physiological standard, however, ^the opposite ^istoagreat ^extenttrue.

The _most essential point ^intheclassification lies in the type grouping ^{dealt with in the} preceding chapter. Certainly ^the genotypic ^seed orchards

guaranteethe genetic quality ^{of the} seed with much greater certainty ^{thando the} phenotypic ^{seedorchards. For the time} being, however, ^{moreattentionis} given ^{totheclassifi} cationof^the phenotypic ^{seedorchards. Thisis} due to the fact thatin Finland almost all the existing ^{seed orchards} belong, so far, ^{to this} group.

It is evident that _most, if not all, ^{of the} existing phenotypic ^{seedorchardsmeet,atleast} in some respect and to a certain degree, ^the

requirements generally prescribed ^for phenotypic seed orchards. It is, however, equally ^evident that they ^differ greatly ^{from one anotherin} this respects. ^{Under the} circumstances, ^{it is} appropriate ^{to divide the} phenotypic ^{seed or} chards, ^for instance, ^{into three classes. The} decisive ^factor inthe classification ^{ishow well} they ^{havesucceededin} meeting ^the requirements

prescribed ^{for a}good phenotypic ^seed orchard, especially ⁱⁿ respect ^{of the} characteristics affecting ^the genetic quality ^{of the seed. It}

seemsbest to employ ^thesame principles as in the classification ^of plus ^trees: parameters important ^{in this} respect ^are listed and the seed orchard concernedis given ^o—3 points ^for each parameter depending on how well they have succeededin meeting ^the goal. ^Thetotal number of points ^received by ^{the orchard} determines theclass inwhichitwillbe register ed. The^classes are identified by ^lettersA,B,^or C. The highest ^{class in Aand the} lowest, ^C.

Each parameter ^to be considered in the classification willbe dealtwithinthe following pages. Also, ^the principles employed ⁱⁿ granting points ^{willbestated.}

PHENOTYPIC SEED ORCHARDS

Clones

Tree breeding ^that applies ^to phenotypic ^seed orchards is based on the so-calledphenotypic mass-selectionprinciple. ^{Thismeansthata}large number of trees, let _us

say hundreds ^of thousands, aretaken

asa starting point. ^Onthe basis of economically important phenotypic

traits, ^aminor portion ^{ofthesetrees isselected} andusedas parents ^{for a}new generation. By repeating ^this procedure ⁱⁿ progenies, ^the degree of improvement (genetic gain) ^{canbeincreased.}

The genetic gain ^ofmass-selection depends ^on the heritability ^{ofthetrait to be} improved ^and

on the selection differentialof the selection.

The _term selection differential refers to the difference ^{between the} respective ^meanvalues of a given ^{trait calculated onthe basis of} an individual _tree and on the basis of ^the sub population ⁱⁿ question. ^{The selectiondifferen} tial _can be expressed ^asabsoluteor ^as divided by ^{the standard deviation} (normalized) ^onthe given ^{trait inthe} subpopulation concerned. ^If the genetic gain ^of mass-selection is marked with G,heritability ^{with h2 and theselection} differential ^with i, ^the following equation prevails:

For the ^timebeing, however, ^ourknowledge^of iand especially ^{ofh2 is}sopoorthat_wecannot obtainaclear picture ^{ofthe benefitthatforest}

tree breeding can derive from mass-selection.

The principles concerning phenotypic ^selec tionortheselectionof plus ^{treeswillnotbedealt} with in this _paper but reference is made to earlier presentations (cf., ^for instance, Sarvas 1953_c, Anderson 1966). ^Itis, however, ^reason able _to emphasize ^{the obvious fact that the} threshold values for different important ^traits employed ^{in the selection of} plus ^{trees deter} mine the selection differential ^of the mass

selection employed. ^{Ifthethresholdvalues are} low, ^{the selection} differential is low, ^too,and the genetic gain ^{remains small.}

In connection with the registration ^{of the} seed orchards, points are given ^onthebasis ^of the threshold ^values employed ^{in theselection} of the clonesusedinthe orchards. The follow ing ^traitsareconsidered:

1. Cubic _contentof plus ^{treecandidate} 2. Knottinessof plus ^{tree candidate} 3. Specific gravity ^of plus ^{treecandidate}

There are thus only ^{three traitsonwhich the} evaluation of the phenotype ^of plus ^{trees is} primarily ^{based.This is dueto the fact that}a

large ^{numberofthemwould rendertheevalua} tion ineffective. However, ^it is, ^of course,

important ^thatthe plus ^{treesare atleast}average

as regards ^{most of those traits which} are

important ^{from the forest} economy point ^of view.

Each cloneis evaluated

separately ^andgiven o—3 points ^{for each of the traitsmentioned} above. ^If the data_necessary for^{theevaluation}

are not available (not measured) ^the score is 0. The seed orchard ^concerned receives the mean valueofthe points given ^{tothe clones.If} any of the above-mentioned _traits has ^been checked by ^{means of a clone} test, the point valueobtainedshouldbe employed.

Phenotypic ^{selection can be checked} by

means of clone _tests. It should be ^observed thatthe significance ^{ofclonetestsisreducedto} thechecking ^ofphenotypic ^selection(except ^for traits with high general heritability); they ^do

not provide ^any far-reaching ^dataongenotype.

However, thefactthatthe phenotypic ^selection

can be checked by means of clone _tests is a

valuable_step forwardin the efforts to increase the degree ^of improvement. ^{Clone tests are} essentially subjected ^{to the} samerulesas

proge ny tests: they ^{have to be} established in the seed's utilization _area. In proportion ^{to the} high ^initial cost and the high cost of main tenanceofclone_tests,theinformationprovided by ^{themis rather} scanty. ^{On account} of this, the numberof clone _tests is fairly ^{small the} world _over. Unlesstreatedin_amanner differing sharply ^fromthe general practice ⁱⁿ silviculture, seedorchards ^and plus ^treecollections_can,toa

certain degree, serve as clone _tests. It should, however, ^beborneinmindthatiftheirlocation

differs from the utilization _area of the seed, certainreservationswillbe_necessary.