Cacao varieties explained


This page will be used as a gathering point for information about cacao varieties that are mentioned elsewhere on my blog. There are many hundreds of recognised cacao varieties, nominal groupings, and clones, so I have no expectation that the information on this page will ever be complete.

Cacao naming conventions: the Hopelessly Vague, the Informative, and the Unique

Some nominal groupings of cacao are so vague as to be nearly meaningless, such as the problematically imprecise Porcelana, and the stubbornly entrenched triumvirate: Criollo, Trinitario, and Forastero.

By contrast, some of the most informative, genetic-based groupings or “clusters” are named after the place in South America where that genetic material (in the form of seeds and/or cuttings) was first collected – such as Curaray, Nanay, and Marañon.

Then there are the cacao clones, which have been tracked, studied, and, in many cases, bred by agronomists over several decades. (Generally speaking, a “clone” is an organism produced asexually from one ancestor. A clone is genetically identical to its ancestor. Cacao trees can easily be cloned by growing vegetative cuttings taken either from the original ancestor, or from any of its clones.)

Each cacao clone is identified by a unique code name consisting of letters and numbers. The letters are often an acronym (e.g. ICS, for Imperial College Selection) indicating a scientific organisation where the clones were first propagated or bred, or an abbreviation (e.g. Mo, for Morona) indicating the general location where the original (often wild) plant material was collected from.

It is worth noting that subjective terms like “superior”, “outstanding”, and “desirable” tend to mean very different things to cacao agronomists and chocolate connoisseurs. In the world of cacao breeding and cloning, yield is king, so traits like disease resistance and exceptional vigour are considered highly desirable. But, in the connoisseurs’ world, flavour reigns supreme, and there is a very common misconception that healthy traits such as hybrid vigour inevitably equate to inferior flavour. That idea is, at best, overly simplistic.

Listed below is some historical, scientific, and/or geograpical information about the cacao clones mentioned elsehwere in my blog. The clone groups are listed alphabetically. You can use Ctrl+F to find a specific clone: all are presented here with a dash (-) and no additional space between the letters and numbers in the clone ID, for example: ICS-95.

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Cacao Clones Explained:

EET – the Estación Experimental Tropical clones. Amores et al provide a brief history of the EET clones in their 2010 report, titled “Cocoa productivity and quality improvement, a participative approach”, commissioned by INIAP (Instituto Nacional Autónomo de Investigaciones Agropecuarias):

    In the late 70′s a group of superior cacao clones were released by INIAP for commercial planting. These were the output of a process that started in the late 40′s and early 50′s. After visiting hundreds of farms in distinct cacao growing zones a number of trees were selected based on visual observations. The high yielders with some disease resistance were identified and selected for further cloning. The clones were used to set up observation plots in Estación Pichilingue [at Quevedo, Ecuador]. Several years of careful evaluation led to the selection of the clones EET-103, EET-96, EET-95, EET-64, EET-48 and EET-19 to be released as a clonal variety of the Nacional type.

ICS – the Imperial College Selection. There are 100 ICS clones. They were selected by F.J. Pound from 1933 to 1935 on behalf of the (then) Imperial College of Tropical Agriculture in Trinidad (which is now the St Augustine Campus of the University of the West Indies). According to Johnson et al’s “Field Guide to the ICS Clones of Trinidad”, Pound made this selection from 15-30 year-old trees already growing in Trinidad (in other words, the ICS clones were selected prior to Pound’s expeditions to the Amazon in search of witches’ broom-resistant cacao). Pound made his selection of ICS clone material by surveying literally tens of thousands of trees. He did this by observing trees in farmers’ fields for two years, and by referring to observations made by growers, and by researchers within Trinidad’s Department of Agriculture. Pound wanted to select a representative sample of Trinidad’s entire cacao population (estimated to be 50 million trees, resulting from centuries of cacao cultivation, hybridisation, and farmer selection) “while not overlooking outstanding combinations of desirable characters” including high yield, exceptional vigour, and large pod and bean size.

    ICS-95 – Described in the “Field Guide to the ICS Clones of Trinidad” (p.7) as a “remarkable individual”: high yielding and very vigorous in Trinidad; yielding well on most soils; resistant to Monilia (frosty pod rot) in Latin America.
    ICS-95 was singled out by Wood and Lass (1985, p.82) as one of the “most valuable” ICS clones due to its reliably high yields and disease resistance. They note that ICS-95 is among the small number of ICS clones which has been introduced to various countries for use as parent stock in breeding programmes.

IMC - Iquitos Mixed Calabacillo. According to Wood and Lass (1985, p.83) the original IMC genetic material was collected by F.J. Pound on an island in the Amazon opposite Iquitos. (Iquitos is the largest city in the Peruvian Amazon.) The original IMC material was collected (in the form of seeds) during Pound’s 1937-38 expedition to the Amazon in search of cacao populations with resistance to witches’ broom disease. The seeds were sent to Barbados where they were grown; then budwood was taken from these seedlings and used to establish 2,500 clones at Marper Farm in Trinidad.
The label “Calabacillo” comes from the unusual shape of these cacao pods (smooth and round) which is reminiscent of the fruit of the calabash tree (Crescentia cujete). Hart (1911, pp.2-4) lists Calabacillo as one of just three “classes” of cacao – the other two being Criollo and Forastero. Hart regarded Calabacillo as “inferior” to both Criollo and Forastero, but noted that Calabacillo trees “flourish where better varieties refuse to thrive” and hence are “strongly recommended as a stock for grafting selected varieties”.

    IMC-67 – Resistant to Ceratocystis wilt; produces flattish, dark purple beans. IMC-67 was one of the parent clones used in the TSH breeding programme (Wood and Lass, p.84).

TSH – the Trinidad Select Hybrids are a series of clones developed in Trinidad by English-born botanist William Freeman. According to Caribbean Icons, Freeman worked as a research officer for Trinidad’s Cocoa Board, where he bred improved cocoa clones and hybrid seedlings during the period from 1956 to 1978. The TSH clones are “highly regarded for their superior yield, excellent flavour and resistance to diseases” (ibid.).
The parent clones which were crossed over three or four generations to produce the TSH clones include: ICS-1, SCA-6, IMC-67, and P-18 (Wood and Lass, 1985, p.84).

    TSH-565 – According to a study by Ram et al (2006), TSH-565 is a descendant of the famously witches’ broom-resistant clone SCA-6. In their evaluation of several SCA-6 descendants, Ram et al found that TSH-565 was the second most productive clone (after TSH-516) following exposure to Crinipellis perniciosa (witches’ broom) and Phytophthora (black pod) in field trials in Bahia.

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