Performance of novel clonal cacao accessions in Hawaii under sustainable farming conditions

Progress report for FW19-349

Project Type: Farmer/Rancher
Funds awarded in 2019: $20,000.00
Projected End Date: 05/01/2022
Grant Recipient: Ninole Cacao LLC
Region: Western
State: Hawaii
Principal Investigator:
Dr. Pierre Broun
Ninole Cacao LLC
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Project Information

Abstract:

Performance of novel clonal cacao accessions in Hawaii under sustainable farming conditions

Despite strong demand for cocoa and chocolate of Hawaii origin, cocoa production in Hawaii remains limited to several hundred metric tons produced on a small number of farms (approximately 60 across the different islands).  There is potential for growth and cocoa, much like coffee production, is a potential high-value economic opportunity for farmers in the State.  One of the limitations of cocoa production in Hawaii is the lack of proven, productive planting materials with good resistance to disease.  Farmers usually use trees derived from seed produced on their own farms, without pollination control.  The result is unpredictable: 70-80% of the cocoa is typically produced from 20-30% of the trees, with an undesirable heterogeneity of growth habits.   More sophisticated production systems rely on clones that have been selected for their productivity, resilience and for cocoa quality.  The benefit is higher, more consistent production and higher uniformity in the plantation, resulting in more cost-effective farm management.

In this project, we propose to test new clones on a 3-acre plot near Ninole.  These clones have recently been introduced by USDA, after years of selection from genetically diverse populations, to combine yield, resistance to disease and cocoa quality.  Ten clones will be compared with locally obtained seedlings.   In order to guarantee the sustainability of the production system, our objective will be to identify a group of 3-4 complementary productive clones, which, used together, will maintain genetic diversity in the orchard, while offering diverse cocoa quality options.   The clones will be grown using sustainable agronomic practices designed to maintain soil fertility and limit waste.

The work will be supervised by USDA and the trial will be used to build awareness in the farming community through a series of information and training sessions.

Project Objectives:
  • Establish an experimental orchard based on clonal cocoa. Our aim is to develop a cost-effective protocol for the development of grafted clonal materials and control seedlings.  This includes comparing direct planting with nursery germination, developing cost effective protection of plantlets against insects, fending off weed competition.  Success measures: rate of survival of seedlings and grafted plantlets, growth rate, plant replacement within a year
  • Compare the performance of clones and seedlings. This will be measured by their rate of development, morphology, flowering time, fruit set, pod index, pod and bean yields, bean size, production per tree, % productive trees, disease tolerance.
  • Develop a sustainable agronomic system to optimize the production of clones and seed-derived trees and minimize the cost of production. Different pruning regimes will be tested for clones and seed-derived controls.  We will compare different ground cover crops and their efficiency vs herbicide treatments.  Success measures, for pruning: productivity, disease incidence and intervention time; for weed control: ground cover index and speed, weed incidence.
  • Raise awareness of the farming community on clonal cocoa management and on new clonal materials introduced by USDA.  This will be done through farm visits and measured through farmer surveys

Cooperators

Click linked name(s) to expand
  • Dr. Pierre Broun - Technical Advisor - Producer
  • Dr. Pierre Broun - Technical Advisor - Producer
  • Machi Dilworth - Producer
  • Dr. Tracie Matsumoto - Technical Advisor (Researcher)
  • Dr. Tracie Matsumoto - Technical Advisor (Researcher)
  • Prof. Chris Somerville - Technical Advisor - Producer
  • Prof. Chris Somerville - Technical Advisor - Producer
  • Dr. Heather Youngs - Technical Advisor - Producer
  • Dr. Heather Youngs - Technical Advisor - Producer

Research

Materials and methods:
  • Establish an experimental orchard based on clonal cocoa

Materials

Clones:  10 clones will be tested:  8 clones selected by USDA in Ecuador and 2 locally selected clones.  The selection criteria for these clones were: pod count, pod index, bean size, resistance to fungal disease (Osman Gutierrez, Cocoa Program Lead, USDA ARS, Miami FL, personal communication).

Seed-derived materials: pods will be locally sourced from experimented cocoa farmers, using trees they recommend.

Trial design:

1-1.5 acres of clonal cocoa will be planted on the upper part of our farm.  Another 1.5-2 acres of seed-derived cocoa trees will be planted as controls.  The trees will be arranged in sets of 2 rows of plants separated by 10’ wide alleys.  Cocoa trees within rows will be planted 6’ apart and the two rows will be planted in a staggered fashion, in order to facilitate access to the trees from both sides, for pruning and harvesting purposes.  The larger alleys should allow for a small tractor to bring materials and haul away pruned branches or harvested pods.   The total number of plants will be approximately 750/acre.

In order to facilitate harvest and traceability, while controlling for environmental differences, the clones will be arranged in 2 blocks of 35-50 trees, alongside 3 blocks of 50 control trees.  The blocks will be randomly distributed and tagged with a unique identifier.

Development of the cocoa plantlets:

Two types of plantlets will be used for our trial: grafted plantlets for clones and seedlings for seed-derived trees.  Grafted plantlets will be provided by USDA: they will have been produced by micro-grafting (grafting onto hypocotyls), on local seedlings used as rootstocks.

Seedlings will be produced in 2 ways: 1) by direct seeding in the field or 2) in the nursery, after growing them for 4-5 months in 4” pots or tubes under shade.  Direct seeding will be done as recommended(Cacao 101: Seed to Pod. H.C. “Skip” Bittenbender – presentation, personal communication)), by planting 2-3 seed and ultimately keeping only the most vigorous seedling.  Nursery grown seedlings or grafted plants will be transplanted into the field at 4-6 leaf stage, taking care that no part of the root is twisted.

Protection of the emerging plantlet

In Hawaii, cacao plantlets are known to be susceptible to rosebush beetles and pigs.  The planted area will be fenced to keep pigs out.  To protect plantlets against insects, they will be placed under a cage adapted from Bittenbender and Caraballo Ferrer (Evaluation of field cage design for seed planted cacao in Hawaii. H.C. “Skip” Bittenbender and Jeffrey Caraballo Ferrer – poster, personal communication). The cages will be removed following seedling establishment.  Several alternative designs are currently being tested and the most effective and least costly solution will be retained.

Weed control (see below)

2 different types of ground cover crops will be planted and compared: a legume, Arachis pintoi (perennial peanut) and a grass, Paspalum viginatum (http://turfgrass.ctahr.hawaii.edu/downloads/seashore%20paspalum.pdf).

Collection of data and parameters measured:

We will keep track of a sample of seed and seedling planted and follow their fate over time (about 200 trees per treatment).  Germination and seedling survival rates will be calculated after direct seeding.  Similarly, we will estimate the survival rate of seedling and grafted plants at 3, 6 and 12 months, as well as the replanting rate.  Development of the plantlets will be evaluated as described below.

 

  • Compare the performance of clones and seedlings.

The following characteristics of the plants will be measured every 6 months for 3 years:

  • Development rate: height, trunk diameter and crown height (for seedlings) – up to moderate pruning limit set below
  • Morphology: canopy diameter – up to moderate pruning limit set below
  • Production: flowering time, number of pods, number of beans per pod (sample of 50 random pods per variety), bean size, average dry bean yield per repetition
  • Disease: % Black Pod infected pods
  • Other: signs of insect damage

Statistical analysis will be performed to evaluate the effect of variety and environment on these different characteristics

 

  • Develop a sustainable agronomic system to optimize the production of clones and seed-derived trees and minimize the cost of production.

Pruning

Two pruning regimes will be tested for clones and seed-derived controls:

  • Severe pruning: plants topped at 7’, diameter of the plants restricted to 5’
  • Moderate pruning: plants topped at 9’, diameter of the plants limited to 6’

Suckers will be removed from seed-grown trees, in order to avoid the development of additional crowns.

This trial will be done on plants that are not included in the variety trial, using 1-2 clones (according to material availability) and control trees. 2 repetitions of 10 trees per treatment will be used at a minimum.

Pod count, pod index and disease incidence willberecorded

Cover crops

We will compare 2 different ground cover crops: a legume, Arachis pintoiand a grass, Paspaulum viginatum, and will compare their efficiency to an herbicide treatment.  After establishment of the cocoa, the relative effect of ground covers will be tested on 2 blocks each, in areas grown in control seedlings – taking care of not interfering with the variety trial, which will be planted with only one cover crop.  2 additional blocks will be left free of ground cover and treated with herbicides.

The cover crops will be compared for vigor and area covered over time (sqft after 1, 3 and 6 months) and for their effectiveness in keeping weeds out (sampling for presence of weeds over several 10 sqft areas).

 

  • Raise awareness of the farming community on clonal cocoa management and on new clonal materials introduced by USDA (see educational outreach below).
Research results and discussion:
2020 Data
Data collected for 2020
Participation Summary

Educational & Outreach Activities

10 Consultations
5 Tours
12 Recruited an apprentice, whom we trained to cocoa cultivation and who is now and employee helping with running the farm
Participated in monthly meetings of the East Hawaii Cacao Association (via zoom).
Set up a collaboration with a neighboring farm to study the Chinese rose beetle infestation
Reached out to HARC to explore possible collaboration

Participation Summary

Education/outreach description:

Educational outreach will be organized in 3 ways: field days, presentation at local and international events (through USDA)

 

Field days

Two field days will be organized, one in year 2 and one in year 3 of the trial. 20-30 farmers will be invited on each occasion.  The farmers will be identified on the basis of a recent cocoa survey (2018 Hawaii Cacao Survey: January to December 2017.  HC ‘Skip’ Bittenbender – presentation, personal communication) and through the local cocoa associations. They will be picked to be as representative as possible of the cocoa farming community in Hawaii.  The farmers will be contacted, with the help of the associations, through a mailing describing the objectives of the field day, the agenda, who will be presenting and who will be in attendance.

The field days will start with a general presentation of the trials, preceding a 2-hour field visit.  The different trials will be presented to the farmers by USDA representatives, seconded by representatives of Ninole Cacao LLC.   After the field visit, a question and answer session will be held and a survey will be handed out to participants.

The survey will include a mix of multiple choice and open questions, covering the following topics:

  • Establishment of clonal and seedling plantations: propagation methods, protection of the plantlets, weed control (main focus of field day 1)
  • Performance of individual clones, comparison of clones to traditional seed-derived varieties (focus of field day 2)
  • Agronomic treatments: ground cover and pruning regimes (field days 1 and 2)
  • Cost and sustainability of the different production models (focus of field day 2)

It will be built following the recommendations of Western SARE.  Several questions will be added on the format of the field day and survey, leaving room for farmer suggestions on possible improvements.  A satisfaction score will be recorded on the field day, the quality and clarity of the presentations, and on the survey itself

A general ranking of the clones and agronomic practices will be inferred from the farmer responses.  Farmers’ comments will be organized and synthesized to help improve the quality and impact of the field days from year 1 to year 2.

A small survey report will summarize the findings

 

Presentation at local event

A presentation of the trial will be made locally at the end of year 3, in front of the East Hawaii Cocoa Association.  This 2nd event will be organized with the association, in coordination with county authorities and USDA.  The event will start with a social gathering to allow for introductions and will be followed by a formal presentation made by representatives of USDA and Ninole Cacao on trial results and field day outcomes.  At the end of the presentation, a question and answer session will be organized.

Highlights of the event will be recorded in a ½ to 1-page article, to be published by the association.  The attendants will be asked to fill a survey on the quality of the event, the clarity of the presentation and on the likely impact the event will have on their own practices.

 

Presentation at an international event

The results of the trials will be shared with lead cocoa scientists within USDA. These scientists will be requested to share these findings in international public or industry conferences or workshops, in which the evaluation of USDA clones or cocoa research in Hawaii is presented.  For this purpose, a summary presentation (1-3 slides) of the purpose and main results of the trial will be prepared and shared with selected USDA scientists during year 3.

Update March 2021

Due to COVID restriction, educational and outreach activities have been strongly restricted in 2020

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.