THE RIGHT KOA FOR YOU…..Charles H. MichlerDirector, Tropical Hardwood Tree Improvement and Regeneration Center

Acknowledgments

• Paul Scowcroft• JB Friday • Christian Giardina• Nick Koch• Mike Robinson• Travis Idol• Nick Dudley• Katie Friday

• James Brewbaker• Creighton Litton• Bob Masuda• Aileen Yeh• Cheyenne Perry• Tom Baribault• Michael Constantinides

Different kinds of koa

• Canoe logs• Elite timber trees• Ecological habitat• Genetic diversity• Adapted to different climates (dry, wet, cold,

frost, etc.)• Wilt resistant• Insect resistant

Population GeneticsTaking advantage of genetic variation that exists within a population or between populations to produce trees or stands with desired suite of traits

Within

Between

Match the genetics of the desirable trees with sites where they are well-adapted and then apply good silviculture

Productive plantations/natural forests occur when you:

Population Considerations• Tend to not want to move populations greater than 1000 ft.

in elevation, but this needs to be tested in the case of koa.– Biggest problems occur when you move material from

a higher to lower elevation • Don’t move populations from areas that have little

environmental variation (rainfall, temperature, etc.) to sites that have much variation.

• Tetraploidy makes it more difficult to predict heritability, but it can be done.

• Long term retention of seed bank can prevent loss of genetic variation due to high-grading (continually harvest the best trees) and alternate land use.

Sources of Population Variation• Mutations

– Unique trait appears such as nut shape, branch angle, or figured wood

• (Natural) Selection of the fittest– Loss of trees that cannot compete

• Gene flow between populations– We take advantage of this in seed orchards by using

parents from different populations

Needs for Genetic Improvement

• Straightness and lack of forking• Volume increase• Wood density???• Crown architecture???• Insect tolerance (Acacia psyllid)– Might be accomplished through management

• Vascular wilt tolerance (Koa wilt)– Often accomplished through resistance of a vector if the

disease is mediated in this manner• Other traits??

Expectations from Genetic Improvement

• 2-4%/year gain (20-25% per selection cycle)– Much higher through genomic technologies (if

funds are available)• Highly heritable– Straightness– Branch angle– Volume– Pest resistance (can be)

Possible limitations to consider

• Type of pollinators and weight of pollen (short wind driven distance) could limit genetic diversity between separated populations– On the mainland, pollinators in many forested

landscapes are becoming or have become absent• Seed orchard design still unclear for insect

pollinated species (we augment pollinators when they are limiting)

Uses of Vegetative Propagation(grafting, rooted cuttings, tissue culture, air layering, etc.)

• Preserve important trees• Multiplication of important trees for further

testing• Deploying elite clones to capture maximum

genetic gain

Nick Dudley, HARC

Development of Wilt resistant koa for Hawai΄i• Moderate to high mortality in mid to low elevations• Screening families at the seedling stage• Developing seed orchard lots to examine durability of field

resistance• Developing resistant populations across most islands and

growing zones• Using tissue culture to bank resistant lines

Development and selection of high quality koa using McIntire-Stennis funds at UH-M

(Turano, Brewbaker, Friday, Idol, and DeFrank)

• Evaluate koa progeny for color and figure• Develop methods for cloning koa/propagate superior

clones• Plant clonal orchards at various locations• Genotype high quality accessions• Determine wood quality of young koa trees• Determine ultrastructure of figured wood

IDENTIFYING THE PRIME TIMBER TREES

KS trees that will be thinned into a seed orchard

HARC A SITE After data analysis and thinning (Forest Solutions)………Ready for progeny testing of best families on DHHL land

Nick Dudley/Aileen Yeh initiated planting and Oriana Krauss/Keith Woeste measured/analyzed

Will analyze wood quality differences among families and also the genetics of seeds in a single pod (one pollen grain may fertilize all eggs in a pod)

High frost tolerance Moderate frost tolerance

Low frost toleranceMatching koa seedlings to the correct elevation

SITE LOCATIONS

Fig. 1. Site Identification and Elevation. B= Bird Corridor (>7,000 ft )P= Kipuka Pu’U (6700–6800 ft)H= Hark A (6600–6700 ft)M= Nine Mile (2200–2400 ft)

Ni’ihau

Kaho’olawe

Kaua’i

O’ahu

Lana’i

Moloka’i

Hawai’i

(Big Island)

Maui

Hilo

Kona

Volcanoes National Park

BH

MP

Waimea

Kilauea

Mauna Kea

Kohala

Mauna Loa

Hualalai

Objectives: 1) Estimate variation in genetics between koa populations in various regions of the Big Island, 2) Evaluate genes vital for survival at varied latitudes in a changing climate, 3) Use NexGen sequencing to identify and characterize genes responsible for critical variations in koa populations.

Which genes involved in survival allow certain Acacia koa to survive at higher

altitudes while others perish?

Upper Range Limit

*Koa can grow at lower elevations however, wilt disease has decimated remaining trees

M Growth range = 1,000 ft

Not adapted = > 1,000 ft north

Not adapted = > 1,000 ft south

Example: Seedling adaptability range

Koa tree survival at varied elevations. Seedpods are usually most viable within 1000 ft of their mother tree.

Without koa trees for nesting, endangered birds are pushed

towards extinction

Next Generation Sequencing (NGS)

Compilation and analysis of NGS datasets. RNA extracted from koa phyllodes was used for NGS to aid in sequence and gene identification.

EXAMPLE DATASET

PhyllodeBipinnate leaflets

Figure formation in wood. Koa growth is made exceedingly complicated by the differences seen in wood from the sawn trees grown under identical conditions.

Which genes are involved in or responsible for the formation of figure in Acacia koa trees ? Why are some “neighbor” trees unexceptional?

ElevationPrecipitatio

nInsects

Soil content

HerbivoresSunlight

A B A B A B

$4 – $8 bd ft $100 – $150 bd ft

Harvest Low Quality Figure

High Quality Figure

Growth Conditions

Identify genetic variation between various koa populations

Evaluate genes vital for survival in a changing climate

Assemble the first koa genome sequence available for public use

Uncover data useful in koa forest restoration for support of endangered native bird species

'I'iwi (Vestiaria coccinea)

'Akiapola'au (Hemignathus

munroi)Koa trees also provide habitat for birds species found only in Hawai’i

Scarification and removal of invasive grasses leads to habitat restoration .

Invasive grasses prohibit growth

Decreased grass cover improves growth

James Leary et al.

Improved Wild tree

Proposed Planting Design with Focus on Crop Trees

Lessons Learned: Plantation prescriptions

• Increase stand density—could be large increase for Koa

• Mixed tropical hardwood species– Silvicultural trials looking at competition

• Start planting with focus on end result– Invest in crop trees or invest in the ecology

• Start with most appropriate seed---the right provenance

What’s needed to be successful

• Long term commitment (Foundation)• Knowledge of basic biology of the species (much to

learn)– Flowering, seed biology, physiology

• Operational and developmental (research) components

• Land for testing• Funds for staff, equipment, infrastructure, and

supplies• Maintained focus (constant worthy suggestions)