Frequently Asked Questions

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What are nematodes?

Nematodes are small, almost microscopic parasitic roundworms that attack the roots of host plants. In Kona the problem is caused by the root-knot nematode Meloidogyne konaensis.

How can I assess if I have a nematode problem?

The most accurate method is to have soil from your farm tested, especially if you are experiencing symptoms previously called "transplanting decline," "replant problem," "nutritional stress", or "Kona wilt." These are all indicators of at least moderate infestation with nematodes.

How do you know that the Fukunaga grafted rootstock plants are the solution? Have you planted any of your grafted trees yet?

Using seed from the two 'Fukunaga' trees at the Kona Experiment station as rootstock give resistant plants. Tissue culture produces rootstock that is identical to the original 'Fukunaga' plants so resistance is assured.

Please explain how tissue culture works. Does it have anything to do with GMO?

Tissue culture is not related to GMO. Tissue culture is simply producing a new plant from a part of an existing plant generally without a sexual cycle. We take leaf tissue from the original 'Fukunaga' trees and generate new plants from this leaf tissue. Since no pollination is required the new plants are exactly like the old ones.

Do other coffee growing areas also use grafted plants?

Many coffee growing areas around the world use grafted plants. Examples are Central America, southern Mexico, Indonesia and Malaysia.

Why should I plant grafted trees if I don't have a nematode problem?

According to a survey by UH researchers, about 85% of the Kona coffee area has at least some Kona coffee nematodes. If you really don't have nematodes at this time there is a fairly good probability that you will get them in the future. Replanting with resistant grafted rootstock will assure that if you do get nematodes you coffee yield will not be affected. Also, you may have a low level of nematodes not enough to kill you trees but enough to reduce your yield. Infection at this level can be difficult to diagnose without testing the soil for the nematode. Planting resistant grafted rootstock will increase profitability by maintaining yield under these circumstances.

I have heard that sometimes other species in the genus Coffea can cross with arabica. Is there a danger that the 'Fukunaga' rootstock could contaminate Kona coffee?

Arabica coffee is unique to the Coffea genus being the only tetraploid species. All the rest are diploid. Since arabica coffee has twice as many chromosomes as the other Coffea species it does not intercross except in very rare instances. This, coupled with arabica's natural tendency to self-pollinate makes it extremely unlikely that hybrid plants would be produced. The rate of cross hybridization in a production crop if it occurred at all would be so low as to have no noticeable effect on cup quality.

Could a rare hybrid seed end up getting planted and result in a whole tree producing inferior coffee? How would we ever solve this problem?

If a rare hybrid seed were to be planted, it would be evident in the nursery as and odd plant and be culled out. The 'Fukunaga' plants have a much different leaf structure and growth pattern which would in part be carried over into the hybrid plant making it easy to detect early on before planting in the field.

I have done a web search and found scientific papers that talk about interspecies crosses in coffee. Are these crosses really so rare?

Researchers have made forced hybrid crosses, generally by using a chemical to double the chromosomes of the non-arabica species and even then viability is very limited due to differences in the chromosomes among the various species of Coffea. You just don't see these crosses at any measurable rate in nature. This is demonstrated by the presence of many different Coffea species at the Kona Station that don't cause problems in adjacent farms.

Can organic farmers use grafted plants whose rootstock is produced in tissue culture?

Yes. Plants produced using tissue culture are allowed as are grafted plants. Although the grafted plants are not grown under organic centification in our nursery, they would be certified organic after being grown for one year under certified organic procedures.

Do 'Fukunaga' plants (C. liberica) have tap roots? Yes. The picture shown is a very young plant with a well developed tap root. Later, many additional roots come off of the tap root to form a well developed root system.

First, thanks for a very interesting and informative web site. Your efforts to make Kona Coffee trees the most healthy are to be commended.

In my search for coffee tree info, one of your competitors states that "arabica" scion material grafted on to "robusta" root stock generates a strong root system resistant to most soil and insect maladies. This grafted tree soon becomes a high 'cherry' producer with vigorous growth characteristics.

What have you heard from the field about these two styles of tree germination?

Robusta rootstock is used in many coffee growing areas (Central America, South America and Asia) to increase resistance to nematodes. However, these places have different species of nematodes than Kona. In fact, the Kona nematode is a unique species, hence the name M. konaensis. Scientists at the University of Hawaii have tested many different rootstock for tolerance to M. konaensis, to date only the Coffer liberica variety designated 'Fukunaga' has shown resistance. M. konaensis happily devours all varieties of Robusta tested. For more information see "Managing Coffee Nematode Decline" Nelson et al. Published by the College of Tropical Agriculture & Human Resources, Univ. of Hawaii, October 2002.