THE DURIAN DARE
SCIENTIFIC NAME: Durio zibethinus
FAMILY: Bombacaceae
Throughout the durian season, people find it difficult to think of anything except the heavenly custard-like durian. On first introduction to a durian fruit, the vicious spines and pungent aroma may make you hesitant. This first impression is quickly dispelled, however, with your first taste, as your mind races to sort out the riot of flavours, memories of other foods, and associations that the taste sets off. You find yourself fascinated and entranced, and wanting more. After a few years, most people look forward to the coming of the season. In a poor season, Malaysians willingly part with up to a day or two's income for a single fruit, rather than miss out on having durian for a whole year.
A durian industry in coastal North Queensland and the Northern Territory has been "about to happen" since the late '80s. Tropical cyclones and the slow maturity of the tree (Durio zibethinus Murr.) has held growers back from a real commitment to substantial plantings. Although the quality of the fruit and its popularity amongst Southeast Asians is well-known, the profitability of the crop is uncertain. Selection of planting material and best culture techniques for Australian conditions in the two growing areas near Cairns and Darwin, have been major problems. Some growers have proven that you can fruit durians in 4-5 years, and this article addresses the selection of planting material.
Small plantings are probably still the way to go, and interplanting with another, faster-growing, species will help finance the venture in the short and medium term. Don't depend on durians for your income or you could be disappointed. Each grower, and durian farmers collectively, will try to find the pathway to a successful durian industry for Australia. Meanwhile, take a few risks and you will get some delicious fruit to eat and sell.
The Durian
Durians are large and long-lived trees. Many produce large crops and provide food and income to their owners over generations. Individual trees or their fruit usually acquire a name, and in time certain trees may achieve a regional renown. With the development of more systematic horticulture in Southeast Asia in the 20th century, some of the best trees have been identified by research agronomists and evaluated and tested in a more or less rigorous manner at research stations. Until recently this process has only taken place in Thailand, Peninsular Malaysia and Java, but it is now commencing in East Malaysia (Sarawak and Sabah), and possibly other countries which grow durian - Vietnam, Philippines and Burma. More recently, new cultivars have been developed through hybridization.
Fruit Description
The durian is highly variable in the size, shape, colour (of skin and flesh) and quality of the fruit. It ranges from 13 to 35 cm (5" to 14") in length; round to ovoid, elliptical, angled, or reniform (kidney) in shape. It has a tough, thick, green, yellow, or coppery brown shell covered with hard, sharp, pentagonal spines either long or short. Different cultivars (cvs.) are harder or easier to open. There are five locules dividing the fruit, with 0-5 seeds per locule, each surrounded by aril that is pearly grey, white, yellow, salmon, or orangey coloured. The flesh is thick and creamy or somewhat watery in texture; sweet with a delicate fruity flavour overlaid (in most cvs.) with a sweet oniony quality. Some have a strong aroma (caused by sulfur compounds), while others have almost none. The more of these flavour/aroma elements that are present in a cv, the more it is said to be "complex." In general, the mild Thai cvs. have a less complex flavour than some Borneo, Peninsular Malaysian, and Indonesian cvs.
The percentage of edible portion varies from 10% to 40%. This is also called the "return" or "recovery" of a cv. To qualify for selection, the return should be at least 25%.
See ref. (3) below for description of other durio species.
General Types of Durian
Yellow-fleshed durians are always delicious, and capable of seducing even the most reluctant gastronome. Generally these yellow to dark yellow types are sweet, creamy, with a strong flavour, but lack the oniony component. In contrast, the greyish-fleshed cvs. are usually more watery and have a more complex flavour including a strong aftertaste. In Sabah, there is a group of cvs. known as "Rajah" ("King") which have silvery-white flesh, and are very smooth and creamy in texture. Their flavour is unique and not like the yellow or greyish types*. In Java too, the silvery-fleshed types are renowned for their complex flavour, relished by durian connoisseurs (most of the population.)
Sources of Cultivars
Most of the early durian cultivars were imported from Thailand. The names were confused, and an early ban on repeat importations prevented correction of the errors for many years. Still, we ended up with some good Thai cvs. This predominance of the Thai cvs, though, has resulted in another problem (see below, Marketing). The famous MONTONG, no.1 in Thailand, is still not generally available, though Gumpun is similar. As for the Indonesian cvs, many hundreds of plants were killed during quarantine under the supervision of AQIS (Quarantine Service), either by methyl bromide treatment, or by other factors. A very few Indonesian cvs did survive, and now new Malaysian cvs are in quarantine. Both these groups will add significantly to the Australian gene pool.
Meanwhile there are lots of seedlings, some 'selected' from good fruits, in the ground. These originated in Borneo, Peninsular Malaysia, Thailand, and Indonesia. It will be another 3 to 10 years before the majority of these trees have fruited, but when this article is rewritten then, it will be a very different story.
Marketing
Durian has proved popular in local and especially Southern markets, although production is small, and good prices are being paid to the grower - $8/kg and above. However, Malaysian and Vietnamese-Australians like smaller fruit, and anyway at the high prices (to $12/kg retail) who can afford a 3-4 kg Thai-type fruit? So it's back to the smaller Malaysian and Indonesian types. Unfortunately, fruit from youthful trees, and that harvested during wet weather, is often of poor quality, and some purchasers have been disappointed after opening apparently good fruit.
Pollination - Is it a Problem?
The botanist Soepadmo** demonstrated that at least 65% of the flowers on a typical durian tree receive their pollen from the same tree. However, for a really good fruit set it would be advisable for a backyard grower to plant at least 2 trees, and an orchardist should plant at least 2 cultivars that have a similar season.
Cultivar Chart - Which One Should I Plant?
Below is a chart detailing the characteristics of durian cultivars as they are known in the country of origin, or since they have been grown here. Also included are the other Durio species for easy comparison. The chart has been carefully assembled with the latest , most reliable information the author could gather.
Availability: all of the cvs. described should be available within a couple of years, if not at present. It is suggested that growers keep this article for future reference, as more cvs are released.
Grafting method: When purchasing trees, the grower may wish to take note of the method of grafting used to produce the young durian plant. Budding produces an upright specimen, while approach-grafted trees have strong lower branches and a more squat appearance. Hypocotyl grafting is a newer technique that should produce vigorous, upright plants.
*see photo of durian "Rajah" tree between pp.80-81 in ref.3
** Ref.5
| CULTIVAR | SIZE | SHAPE | SKIN COLOUR | FLESH COLOUR | FLESH THICKNESS (%Edible Portion) | TASTE | TEXTURE | YIELD/COMMENTS | AVAlL- ABIILITY |
| Thai Cultivars | |||||||||
| GUMPUN (Aust. Montong | Large-v.large | Heart-shaped | Green | Dark yellow | Thick 36% | Good, sweet, mild, rich | Fine, very firm, smooth | Aborted seeds. High yield. Can be picked early. Late season. Sensitive to cold weather. Vigorous | G-R |
| CHOMPOOSEE | Large | Yellow | Thick 34% | Good | Soft | High yield. Early season. Precocious bearer. Cold weather sensitive | G-R | ||
| D98 | Large | Almost round | Light leaf green | Creamy white | Thick 32% | Creamy, sweet | Firm | Medium quality, good yield, Mid-late season | G-R |
| GAAN YAOW (Aust.) | Very large | Long pointed | Green | Yellow | Thick 28% | Mild, sweet | Creamy, fibrous, fine. | Similar to Gumpun. Mid-late season | G-R |
| GOB YAOW | Thick 28% | Firm | Good yield. Mid-season | G-R | |||||
| GOB (Aust. Chanee) | Very large | Long, pointed | Yellowish-green | Pale yellow | Very thick | Good, mild | Uneven, firm | Aborted but large seeds. Crops well. Bears ou of regular season. Disease problems in ripe fruit. | G |
| MONTONG | Very large | Heart-shaped (often irregular) | Gree, Lemon Green | Yellow | Very thick | Good, sweet mild, rich | fine, creamy, firm, smooth | Locules bulge above sutures. Large spines. Aborted seeds. High yield. | A |
| GAAN YAOW (in Thailand) | Large | Round 5-6 locules | Green | Pale yellow | Medium | Sweet and rich | Creamy, smooth, fine | Long stalk, narrow spines. Very popular in Thailand. Slow to fruit. Early season. | G |
| CHANEE | Very large | Long, pointed, reg.locs. | Green to gold | Dark yellow | Medium thick | Moderately sweet, slightly bitter | Creamy, fibrous | "Chicken flesh" | NA |
| DAWN'S MONTONG | Med. large | Heart, irreg. | Greyish or purplish green | Yellow | Medium | Excellent, complex | Firm | Vigorous. Precocious. Medium yield. | G |
| Indonesian Cultivars | |||||||||
| SUKUN | Medium | Long, rounded | Bronze | Creamy white | Very thick | Excellent, complex | No. 1 Indonesian cv. Seedless | NA | |
| HEPE | Medium | Oblong | Yellowish green | Creamy white | Very thick | Excellent, complex | Seedless, Photo ada. (extra small seeds) | A | |
| SUNUN | Small | Good | Tree has dwarf habit. Crops heavily. | G | |||||
| PETRUK | Medium | Oblong | Bronze | Golden | Thick | Good | Grows well. Bushy habit. | G | |
| SITOKONG | Medium | Yellowish | Pale yellow | Thick | Good, strong | Firm | Old Dutch selection. Hardy | A | |
| CULTIVAR | SIZE | SHAPE | SKIN COLOUR | FLESH COLOUR | FLESH THICKNESS (%Edible Portion) | TASTE | TEXTURE | YIELD/COMMENTS | AVAlL- ABIILITY |
| Malaysian Cultivars | |||||||||
| D2 | Medium, 1.35kg | Long Irreg. pear | Bronze-green | Golden yellow | Thick 25% | Creamy, sweet, delicious, complex | Fine, soft, slightly coarse. | High quality, low yield. Popular cv. Aborted seeds. Mid-season. | A |
| D7 | Medium 1.26kg | Oblong | Greenish | Golden yellow | Medium 21% | Creamy, sweet | Fine | Medium quality, med-high yield, keeps well without fridge. Early season. | A |
| D10 | Small 1.0-1.5kg | Oblong | Greenish yellow | Saffron yellow | Thick | Excellent, creamy, sweet | Firm | Medium yield. | A |
| D16 | Medium 1.35kg | Round | Dark green | White | Medium 27% | Creamy | Fine | Medium quality. Good yield. | NA |
| D24 | Small 1.2kg | Round but long | Light green | Yellow | Medium 23% | Creamy, sweet, a little bitter. Strong aroma | Fine, firm, smooth, dry. | High quality, high yield. Reliable cropper. Slow and hard to grow. Keeps well. Mid-season | A |
| D99 (Thai) | Small 1.0-1.5kg | Round but irreg. | Light leaf green | Saffron yellow | Medium | Creamy, sweet. | Fine, firm. | Medium quality. High yield, consistent bearer. Small tree. Early season | NA |
| D101 | Large | Round or long | Dark green | Yellow | Thick | Sweet and delicious | Soft | Good quality. Medium yield | NA |
| D123 (Thai) | Large 1.8-2.5kg | Long, narrow | Bronze | Golden yellow | Thick | Creamy, sweet | Moderately soft. Slightly coarse. | Good quality, good yield. Reliable cropper | NA |
| D145 GREEN DURIAN | Medium 1.4kg | Round | Dark green | Golden yellow | Medium thick | Creamy, sweet. | Smooth | High quality, medium yield. Disease resistant. | NA |
| D168 GOLDEN MUAR | Medium 1.5kg | Round | Dark green | Golden yellow | Thick | Creamy, very sweet | Firm | High yield, reliable cropper. Easy to open. | NA |
| MDUR78 | Medium 1.5-1.8kg | Round, irreg. | Yellowish green | Yellow | Thick 20% | Creamy, sweet. | Smooth, soft. | High yield, reliable cropper. Tree mod. small (squat) and disease tolerant. Keeps well. | A |
| MDUR79 | Medium 1.0-1.6kg | Round | Dark green | Deep yellow | Thick 27% | Creamy, sweet. | Fine. | Medium yield, reliable cropper. Easy to open. Tolerates stem disease. | A |
| PENANG HILL | Medium | Oblong | Bronze-green | Pinkish white | Medium | Complex, delicious | Soft, watery. | Selected for exceptional taste. | A |
| 601 | Medium | Oblong | Bronze-green | Pinkish white | Medium | Complex, delicious | Soft, watery. | Selected for exceptional taste. | A |
| RED PRAWN | Medium | Oblong | Bronze-green | Pinkish white | Medium | Complex, delicious | Soft, watery. | Selected for exceptional taste. | A |
| CULTIVAR | SIZE | SHAPE | SKIN COLOUR | FLESH COLOUR | FLESH THICKNESS (%Edible Portion) | TASTE | TEXTURE | YIELD/COMMENTS | AVAlL- ABIILITY |
| Australian Cultivars | |||||||||
| LIMBERLOST (Cairns) | Medium | Oblong | Green | Cream | Thick 33% | Good | Soft | Good yield, some empty locules. Early season. | G-R |
| JACKIE M. (Kuranda) | Medium | Heart-shaped | Golden yellow | Cream | Medium | Good, mild, sweet | Moderately soft. | Vigorous grower, evenly filled. Self-pollinating. Medium yield, so far | G |
| Durio Species | |||||||||
| LAI (D. kutejensis) | Small to medium | Ovate to oblong, Soft spines. | Yellow | Orange to red. | Medium to thick | Moderately sweet, tangy. | Very firm. | No aroma. Highly variable. Several races available in NQ. Some cvs. excellent. Precocious. | G |
| TUTONG (D. dulcis) | Large | Round, needle spines. | Red | Pale yellow | Thin to medium. | Very sweet flav. like pineapple cream | Soft | Doesn't split. No cvs. Aromatic shell. Slow-growing, tender tree. | G |
| ISU (D. oblongus) | Small | Round, long spines | Green to yellow | Yellow | Medium (varies). | Moderately sweet, tangy (flavour varies) | Thick, sticky | Like a fruity peanut butter. No aroma. Opens easily. Vigorous, root rot resistant | A |
| ISU RAMIN (D. oblongus) | Small | Round, long spines | Green to yellow | Orange | Medium (varies). | Moderately sweet, strong tangy flavour. | Thick, sticky | Vigorous, root rot resistant | A |
| RED-FLESHED (D. graveolens) | Small | Round, long spines | Orange | Red | Medium | Not sweet. Mild durian flavour. | Very firm. | Cheesy. No aroma. Must be picked from tree. Good yielding cvs. identified | A |
| BELUDU (D. oxleyanus) | Small | Round, very long spines. | Greyish green | White to pale yellow | Medium | Sweet, creamy. | Firm, fine. | Most similar to durian. No aroma. Hard to grow. | G |
| AVAILABILITY: | G Available from one or more local nurseries. A - Clone introduced into Australia. Available in the future. R - Trialled by the DPI - Recommended. NA- Not available in Australia at present. | ||||||||
Comments on these and other cultivars:
GOB YAOW, CHOMPOOSEE - Although grown and evaluated by the DPI, no description available.
D96 (Bangkok A) - A medium to large, heart-shaped, bronze-green fruit with moderately thick, creamy sweet golden-yellow flesh of fine texture, and generally of excellent quality, is no longer recommended because of poor yield. One grower said the seeds were very large, as was the fruit (to 4.5 kg) and consequently hard to sell.
MONTONG - There are reported to be 28 cvs. of Montong in Thailand. Over time, Thai growers have selected 'sports' (mutants) or outstanding seedlings (of Montong parentage) as having better flavour, etc., than the 'current model' Montong.
MONTONG cv. introduced from Hawaii, in Australia but identity uncertain.
LUANG - available, but no information.
HEW 3 - A popular, precociously-bearing Malaysian cv., with firm, yellow flesh of medium thickness, is not recommended because of poor yield.
HEW 1, 2, 5, 7, and 8 - in Australia, but no information.
KK8 or Kradoum Tong - Vigorous grower but poor yield.
D102 - This Thai-type cv. is available. The large, bronze-green fruit has thick, yellow flesh which is soft and good to eat. Claimed to be precocious.
D16, D123 - Error in original importation. Not recommended. Correct clones not available.
D99 and D24 - In a survey of 42 older Malaysian clones, these were the highest yielding cvs. D24-Extolled by visitors to Malaysia. Highly recommended there by the Agriculture Dept. The fruit are distributed evenly along the branches, thereby preventing strain on the branches from the high yield.
MDUR78 and MDUR79 - These are 2 new hybrid durian cultivars, the results of a 20-year development program. They were selected on the basis of yield, quality of fruit and other criteria. MDUR78 is the progeny of D10 ( female) X D24 (male). NDUR79 is the progeny of D24 (female) X D10 (male).
SITEBEL, CIPAKU - Poor % edible portion. Not recommended.
CIPAKU - seedlings being used for rootstock (believed to impart disease resistance.) Crops heavily and early in the season.
SUKUN ('Breadfruit') - an excellent fruit, the tree is being rapidly propagated in Indonesia. Researchers walked three days from the nearest road to locate the parent SUKUN tree. It is hoped someone will be able to import this clone.
PETRUK - So-called 'marriage durian,' because it marries the characteristics of delicious Malysian cvs. with the thick flesh of Thai cvs. It should become popular here.
SUNAN - is proportioned half-size of other cultivars. Woody parts grow well, though.
PARUNG ("Seedling of Montong") - A small, green fruit with thin, dark-yellow flesh of good flavour, it exhibits rapid growth and is a late season fruit. Subject to bark disease.
SORROW - A local cultivar from Cape Tribulation, this is a small fruit, elliptic (torpedo) to pyriform (teardrop) in shape, with small spines. It was unaffected by Phytophthora palmivora damaging other nearby trees.
PENANG HILL 601, RED PRAWN, and 88 - These cvs have a delicious and complex flavour that is eagerly sought after by connoisseurs. Consequently, although they may be only average in their % edible portion, and their yield is unknown, very high prices are gained for them.
LAI - Many excellent trees in East Kalimantan. Cvs. in Java. It may be possible to boost the growth with extra rootstocks of the regular durian.
TUTONG - Better fruits from East Kalimantan. May also be boostable.
ISU and ISU RAMIN-Very beautiful tree and growing well in NQ. May be useful as a rootstock for the durian in wet conditions. Some authors have confused this species (D. oblongus) with D. graveolens. However the dark-green, gold-backed leaves are distinctive, and the fruit drops when ripe.
RED-FLESHED DURIAN-Satisfactory growth in NQ; can be boosted. Also itself being tried as a rootstock for the durian.
BELUDU-Widespread in Southeast Asia. Seedlings vary in appearance and vigour.
'WILD' DURIO SPECIES-are being grown in NQ with mixed success, or have yet to be imported. These include the:
TORTOISE DURIAN (Durio testudinarium),. which bears a heavy crop of small but edible fruit on the bottom 1-2 metres of the trunk and lowest branches. It is, however, extremely slow-growing. The author's 2 trees are both 1.7 m tall after 5 years.
MOUNTAIN DURIAN (Durio kinabaluensis) grows only on certain mountains in Sabah, Borneo, at an altitude of about 1500 m. However, before you jump to the conclusion that this tree will thrive in Tasmania, note that these mountains have a cool but very equable climate, and frost would not occur. In Australia.
Durio macrantha (Kosterm.) Kosterm. This new species, identified in 1992,is native to Sumatra. A fast-growing and precocious tree, it produced a heavy crop of large, high-quality fruit. The arils had the same taste, aroma, and texture as the durian.
SEEDLINGS - Even with all these cultivars available or coming, don't neglect the planting of seedlings. Preferably, the seeds should be collected from known good fruits, and you must be prepared to wait. However, growth is generally rapid and an impressive tree results. Normally you will have to wait ten years for the first flowers, but JACKIE M. flowered in the sixth year, while other trees have not flowered after 13 years. So plant at least double the usual number of trees, or plant them at half the usual spacing, to allow for future removal of poorly-fruiting trees. You could be doing us all a favour if your seedling turns out to be the 'miracle' cultivar we are all looking for.
References:
1. Information on Malaysian cultivars from Dept. of Agriculture, Peninsular Malaysia, with up-dates from elsewhere.
2. DPI publications for data on trees grown at Kamerunga H.R.S., Cairns. This work has now ceased with the closing of the station, but a small orchard has been established at South Johnstone Research Station, where it is hoped further work will be done, and new cvs. planted.
3. Tropical Fruits, by Glenn Tankard, Viking Penguin, for further information about Durio species.
4. Penanaman Durian, by M. Zainal Abidin, S. Ahmad Tarmizi, and O. Azizar, MARDI, Kuala Lumpur, 1992.
5. The Reproductive Biology of Durio zibethinus Murr., by E. Soepadmo and B.K. Eow, GArdens' Bulletin, Singapore, XXIX (1976), pp 25-33.
Acknowledgements: Thanks to the many growers who assisted the author in compiling this article, especially Colin Gray, who was very generous with his time. Thanks also to Ian Edgerley who assisted with translations. Any errors are the responsibility of the author.
DATE: March 1993
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