D168 durian

The first D168 I cut open in my San Diego greenhouse smelled of warm custard with a thread of almond behind it. Most first-timers brace for a sulfur wall that never quite arrives with this variety. That fruit weighed 1.6 kg, dropped onto the netting I sling under every tree at dawn, and I ate it before lunch the same morning.

This Johor durian carries more aliases than anything else I grow. On our Exotic Fruits and Vegetables plots it goes on the tags as D168, but buyers know it as IOI, Mas Muar, Buaya Emas, or the mislabel D101. Getting the code right matters, because the number you graft decides the fruit you harvest four years later.

The durian everyone calls by the wrong number

D168 was registered with Malaysia’s Department of Agriculture on 24 May 1989, under the official name Durian Mas Hjh. Hasmah. The mother tree grew in a backyard in Muar, Johor, planted by Hajah Hasmah Haji Hashim, who propagated it after squirrels kept stripping her original crop. She paid a neighbor in seeds and cuttings to deal with the squirrels, and that payment is how the variety left her garden at all.

The market name “IOI” came from stalls near IOI Mall in Kulai, where sellers chalked “DIOI” on their boards for “Durian IOI”. Customers read the handwriting as “D101”, and that misreading stuck so hard that most Malaysians now buy this fruit under a code that officially belongs to a completely different Thai-origin variety.

The fruit itself runs round and medium, averaging about 1.5 kg with a greenish-brown husk and a short, stocky stem near 4 cm long. The Department of Agriculture description calls it “senang dikopek”, meaning easy to pry open, and that holds up: the shell splits along the suture lines without a fight. Inside sits orange-gold flesh, firm and medium-thick, with flat seeds that tend to run large.

Telling it apart from a fake Musang King

Sellers pass D168 off as Musang King constantly, because the golden flesh reads as premium and one of its nicknames, Wang Zhong Wang, translates as King of Kings. The tells are the flat seed (Musang King seeds sit more elliptical), the taste, which leans lemak manis or rich-sweet with only gentle bitterness, and the price.

If a stall offers “Musang King” at a third of the going rate, you are almost certainly looking at D168 with a costume on. Ask yourself before paying premium money: would you know the flat seed and the sweeter finish by touch and taste, or only by the sign?

Here is what I check at the stall or under my own trees, in order of how fast it settles the question:

• Stem: short and stocky, roughly even in diameter, about 4 cm.
• Seeds: flat and on the large side, flesh peeling away clean.
• Flesh color: warm orange-gold rather than the turmeric-yellow of Musang King.
• Aroma: moderate and approachable, not room-filling.
• Finish: sweet and creamy first, a light bitter note second.

Growing a Johor lowland durian in a San Diego greenhouse

Durian wants tropical lowland heat, and San Diego does not supply it outdoors. Mean daily temperatures below 22 C, roughly 72 F, stall the tree’s growth outright, and my winter nights drop far below that. Everything I do here fights the climate, which is why my whole planting lives under a heated polytunnel held above 70 F at night from November through March.

My substrate is a sandy loam cut with about 30 percent pumice, in raised beds a foot high, because the shallow feeder roots rot fast in standing water. Every tree is a grafted scion on kampung rootstock, which fruits years earlier than seed and holds the parent flavor true. A seedling here would be a decade-long gamble with no promise the fruit matches its parent.

Rig soft netting a few feet under the canopy before the fruit sizes up. A ripe durian drops on its own, and a 2 kg spiked fruit hitting a concrete floor splits and bruises the flesh within minutes.

Cost is the part nobody warns you about. One January my greenhouse heater failed overnight, temperatures fell to the low 50s F, and I lost the entire flush on a six-year-old tree plus the tree’s momentum for that whole season. The heating bill to hold a durian house through a San Diego winter runs several hundred dollars a month, and I fold that straight into what each fruit really costs me.

The establishment sequence I follow with a new grafted D168:

1. Pot the graft up gradually, never jumping more than one container size, to keep the taproot from circling.
2. Hold daytime warmth at 80 to 88 F and night above 70 F through the first three years.
3. Irrigate to roughly 2 inches a week, backing off only to trigger flowering.
4. Impose a dry spell of 3 to 4 weeks once the tree is mature enough to flower.
5. Resume heavy watering the moment flower buds set, or they abort.
6. Thin the fruit hard, leaving only what a young tree can actually carry.

Before you plant a single graft, run the numbers on whether your site can even hold the heat this crop demands across a full year. The calculator below scores a location’s temperature, rainfall and humidity against durian’s tolerances and flags the months that fall short.

Harvest, flesh, and whether the payoff lands

Durian tells you it is ripe by dropping, and D168 punishes you for waiting. This variety eats best the day it drops, and by the following day the flesh has already slid past its peak. That short window is the single hardest thing about selling it fresh, and it shapes every harvest morning I spend crawling under the trees with a headlamp.

A durian eaten six hours off the tree and the same durian eaten a day later are barely the same fruit. Fresh is the whole point of growing it yourself.

The flesh-to-seed ratio is where D168 both wins and loses. The flesh is generous and creamy, yet the seeds run flat and large, so you give back some edible volume that a small-seeded variety would keep. A mature Johor tree throws 400 to 500 fruits in a season; my best greenhouse tree, in a good year, gave me nine. That gap is the honest math of growing a tropical giant in Southern California.

In its home market D168 is the smart-money pick: golden premium-grade flesh at roughly a third of the Musang King price, which is why families there buy it by the crate for weekend gatherings.

D168 loses quality fast once cut and warmed. If you cannot sell or eat a dropped fruit inside a day, are you set up to freeze the pulp cleanly, or will you watch good flesh turn to waste?

Pricing in the United States is a different animal, since novelty and scarcity, rather than yield, set the number. A single greenhouse-grown fruit here can fetch what a whole crate costs in Muar, which is the only reason the heating bill pencils out at all.

To split a whole fruit into what you can actually eat versus rind and seed, the tool below estimates edible flesh weight and the flesh-to-seed percentage from a fruit’s total mass and size grade.

Is D168 worth planting

For a tropical lowland grower in Johor or Pahang, this is close to a default choice: consistent, rain-tolerant, heavy-bearing, and easy to sell. The variety earns its reputation on reliability rather than shock value, and it forgives the weather in a way the pricier clones do not.

Anyone north of the tropics should plant it only if you can genuinely hold night temperatures above 70 F year-round and stomach the heating cost that implies. My San Diego D168 will never out-yield a Muar orchard, and it was never going to. What it gives me is a fruit that drops at dawn, gets eaten by noon, and tastes of custard and almond in a climate that has no business growing it at all.