Article from the Tropical Fruit News magazine of the Miami Rare Fruit Council International
Lecture by Dr. Richard Campbell, Curator of Tropical Fruits at Fairchild Tropical Garden

The Promise of Jakfruit
Reported by Bob Samack

Dr. Campbell gave us a brief introduction to the fascinating jakfruit. "It is everywhere" in Malaysia, Indonesia and India. "The ripe fruit are eaten, the green fruit are used as vegetables, the wood is used to make buildings, lumber, they use the seeds in cattle feed. You can also cook the seeds in fire ... The culture just fits into the whole life in Asia. Jakfruits were brought to the New World by the Portuguese into Brazil in the mid 17th century.i.All through Rio de Janeiro and Bahia and in different area of Brazil you do find very large jakfruit trees. "

Dr. Campbell began his slide presentation, showing jakfiuit trees with good sized fruit, growing in a parkin downtown Rio de Janeiro. "Last Christmas I found a fruit in the botanical gardens the weight 125 pounds .. on a tree that was growing up on the hillside .. a pretty impressive fruit; These are huge trees, all seedling grown that have been planted a long time ago. and there are seedling trees spread all throughout this area .. some of these jakfiuits are good and some .. are bad.

 "There are two distinct types of jakfiuits found in this area of Brazil just like .. in Asia .. soft jaks and .. crisp jaks. Some of them are extremely soft which I must admit take a little more getting used to than the crisp ones because the soft ones kind of lay in you throat like a slug .. They are very good but do take a little bit of getting used to. Some of the crisp ones ... might be more palatable to some people.

"Jakfruits were brought to Florida over 100 years ago. There used to be a tree in Matheson Hammock (and) trees in Coconut Grove ... planted over 80 years ago. Mostof those trees are gone. The problem is in South Florida we have hurricanes so the trees can't get real big ... " They also succumb to cold, disease or other problems. He showed a slide of a "tree ... that was at the University of Florida experiment Station in homestead .. brought in 1935. (It) is still there and still produces crops like this every year. They never ripen to maturity because they are stolen .. In about a month after this they will be gone. They ... are right by a parking lot and prime targets . .A few big trees around do put on good crops like this. II

At the University of Florida's Tropical Research Education Center (TREC)·are two jakfruits which are grafted trees from Thailand: TREC #1 and TREC #2. "One is pretty good quality. Now things have changed in jakfruits." Before, local trees were seedlings. "Then people started to get a lot more interested in jakfruit, for instance the RFC. Many of the people in this room, the people that brought in NS-1, ( are) the people that brought in Tabouey and other named cultivarsout of Asia, Thailand, Australia and other places." Jakfruit "has gone from more of a backyard curiosity to a potential commercial crop (and) a wonderful tree for your yard. We really have turned the comer from these very large trees that just gave you a couple of fruit, to now (when) you can grow them as a crop (with) a lot of different cultivars.

"At the fruit program at Fairchild Tropical Garden, I was fortunate enough when I came in to inherit a large number of grafted jakfruit trees in a greenhouse ... (from) Australia, Thailand, Indonesia, Hawaii, Sri Lanka and a few other places. These were very large trees and in desperate need to go into the ground. So this is immediately what we did, "They were planted out "into a collection on the property of the Montgomery Foundation where we have our FTG collections .. .in June of 1992." These named, grafted varieties were all labeled, with excellent records as to their source and history.

"Then of course, Hurricane Andrew came in August ... and pretty much leveled the collection.'! Slides depicted the orchard soon after Andrew's wrath, and about six weeks later. Some of the jakfruits were left standing. "This was quite a distressing thing to me ... The amazing thing about jakfruit however, is that once we did set them up they survived and started growing again."

The jakfruit trees had been held in containers for five or six years, and when planting them out, Dr. Campbell discovered they were severely rootbound. "You put them in the ground and they would just sit there. Then, of course, hurricanes flattening them doesn't help either." To encourage the young jakfruit, they started approach-grafting them in the field:

"I planted a seedling next to the trunk of the tree that was weak and not growing, and opened up a hole in the existing jakfruit and stretched the seedling right up to the cleft that I had cut into the existing tree ... after you do that, when you cut the tops of the seedlings off after they took, (are) two seedlings stocks growing into that tree ... giving that tree a whole new root system. The roots of that tree were so wound around you could have screwed (it) into the ground ... lt had quite an effect." He showed slides of trees which displayed much healthy growth after about six weeks, and after a year." We got an incredible response in out trees ... very good new growth and a great deal of vigor ... they started growing again like they should ... We got blooming starting in that collection in January and February of 1993 ...

"He showed a picture of a jakfruit called "Black Gold" which was only five feet tall, bearing five fruit on it. One of the nice things about jakfruit is that "you really have to search to find a pest". He showed a slide with a chewed petiole: right after Andrew there was a lot of this type of puzzling damage; Eventually they found it to be from 10 moths, which normally feed on mangroves. "We are right on the bay and when the mangroves got destroyed (the moths) came into my jakfruits and defoliated limbs ... but jakfruit really don't have a lot of diseases or a lot of insect problems."

He showed a mango photo to make a point: "Florida has become a center for diversity for mango cultivars" over the years as germplasm from around the world has been established here and cultivars selected out and sent back out globally. Dr. Campbell believes the same thing should be done with jakfruit; at present they have 19 cultivars from several countries in their collection.

"We want to make use of this wonderful resource that we have. So how are we using it? ... Bob McNaughton has been working with us a lot in Articarpus, and injakfruit specifically, doing genealogical work, that is, measuring fruits. I personally had no idea how log it was from blooming to ripening of a jakfruit. I needed to find out some basic things so 1 know how many days it is until I have a jakfruit ripe. So we did growth curves. We measured fruit every three days in the field to see how they grew when they ripened and then started doing evaluations That's been some very important
work. . . in the collection.

"Then back to this idea of using this genetic resource we have. What is nice about jakfruits is you can do controlled crosses on them very easily. Besides just letting the trees in the collection outcrop with each other, exchange pollen by pollinators or by wind, I'm helping them along a little bit ... we're taking male blooms ... rub your hand down it to get pollen allover your hand ... go over to your female bloom on the other tree and just rub you hand on the female inflorescence, then throw a bag over that whole thing. And you do that every day basically. We go out and pollinate these jakfruits of specific varieties. I'm pollinating Black Gold with Gold Nugget, Gold Nugget with Fa-Talom, Fa-Talom with Dang Rasimi .. Then the idea is to distribute seeds as well as trees to people like you all in here. 1 want to see these things growing out and select out new seedlings from this collection."

A slide showed a "diseased fruit lip there, that black male bloom. I hear a lot of people talking about what do you spray to control that black fungus on jakfruit. There is no reason to spray to control the black fungus. (It) ... comes in on the male bloom after it's dying or going down hill. So if you ever see this on your jakfruit tree, don't go looking for something to spray it with. That's perfectly normal and you can take this fruit and rub it all up against a female fruit .. don't worry about it.

"The other idea besides distributing seeds from this controlled process is propagation. This is a good hot topic. If any of you know how to graft jakfruits out there I'm going to bar the door and pick your brain. I've been doing veneer grafts on these to make trees for the fall sale. We will have quite a few trees for sale at the fall sale for FTG this year ... AII the cultivars we have fruiting now we will have available. I don't know how many we'll have because jakfiuit are difficult to propagate vegetatively. They are difficult to graft. What I've been doing is veneer grafting them like this when they are very vigorous in the late fall and early spring. and actually I've been having pretty good success with it. You put a veneer on like that and the leaf will break out two Of three days .. It's been pretty successful. I've been getting 60 to 70 percent survival so far thisspring on grafting these. But we're talking about limited numbers so don't hold me to this. I don't want to say that it's a great way to graft jakfruits because I haven't done it enough to know. But that's the other idea with the collection. We want to take these cultivars and get them out into the public so people can start testing them out there."

He read their list of cultivars: "Black Gold, Tina, Dang Rasimi, Delightful, Leung Bang Bong, Galaxy, Gold Nugget, Hess, Honey Gold, 1-30 and J-31, Lemon Gold, NS-1, Tabouey. We have different seedlings out of Brazil. .. a couple of seedlings out of Indonesia. We have Dr. McNaughton's giant jakfruit, which .. started sprouting out like crazy and is doing real well. Also Leung Bang Bong and both of the seedlings out of TREC. we have two to three, hopefully, of each of the cultivars in the collection."

Due to the hurricane, his collection has "only seen one good year of fruiting ... Last year we had quite a lot of fruit and this year we're going to have much greater fruiting ... A little six foot tree last year put on seven jakfruit averaging about 25 pounds and very good quality" His slide displayed one that "was a little bit far gone. It had come off in the heat of the summer and we didn't find it for a couple of days .. .1 had it in my office and it scared everyone out of the building when it started ripening. One thing you have to be careful about jakfruits is your family may not like you if you have one ripening in your house ... some do have a strong aroma (like) Black Gold ... The quality is very good with this jak but medium crisp, a little bit less crisp than NS-l, at least the fruit-we had last year. We now have fruiting on all three of the trees we have .. We are probably going to get a lot more evaluations on this tree this year. It is quite precocious. These trees that are fruiting have only been in the ground for two and a half years and were grafted in '90. So they're five years old. The seedlings could have been older.

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Samack, Bob. "The Promise of Jakfruit." Tropical Fruit News - Vol 28 No.9 Sept. 1994. Web. 5 Oct. 2015.

Published 24 Jan. 2017 LR
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