The first thing that a durian farmer or grower must do right the first time is when sourcing for durian saplings. The issue is not about not getting a fair price for the saplings bought but rather to buy the correct clone type saplings that one intends to grow. The mistake that could happen (and it happens quite often) is when a grower buys the wrong clone type saplings only to know it after the tree has bear its first fruit. This will be 5-6 years down the road. Some of the clones do exhibit specific characteristics mostly in its leaf shape or form or even color (eg: the Musang King or D197 has a wavy form at the edges of its younger leaves) while the Duri Hitam or D200 clone exhibits droopy branches. These characteristics could help the farmer or grower to identify the clone. The issue nonetheless, is some clones exhibit similar or identical characteristics while some does not even have special characteristics at all. The safest bet for a farmer or grower in getting the correct clone types is by sourcing saplings from an SPBT certified fruit plant nursery. SPBT or Skim Pengesahan Bahan Tanaman (Planting Material Verification Scheme) issued by the Department of Agriculture. This SPBT certification scheme does not only apply to durian saplings but to most tropical fruits such as mango, jackfruit, pineapple and mangosteen whereby the Department of Agriculture shall verify the clone/cultivar type and records the origin of the matured trees upon which the scion or young stem/shoot is taken for grafting by the nursery. These record documents the verification and trace-ability of the scions or other vegetative propagation materials that the nursery sources for its clone seedlings grafting activity. It has to be said that this scheme is for clone fruit saplings and not heirloom saplings of any fruit. Farmers and growers could sourced their durian saplings from these certified fruit nurseries which are listed in the Department of Agriculture's website at http://www.doa.gov.my/index.php/pages/view/399 . This list will be updated periodically. As for myself, I sourced my saplings from three certified nurseries in Kajang, Muar and Bidor. I once bought 2 Musang King saplings from Universiti Putra Malaysia (UPM) , formerly the Malaysia Agricultural University. This university managed plant nursery doesn't have an SPBT certification but I do trust them. I would like to advice that not all nurseries with saplings planted in polybags bearing the Department of Agriculture's logo are SPBT certified. Likewise, a normal polybag without the department's logo does not indicate that particular nursery doesn't have an SPBT certification. Why buy grafted durian saplings? In Malaysia and I would believe likewise in other durian producing countries, there are 3 categories of durians. One is the native durians, another is the clone durians. The last category is the wild or jungle durian. The native durians are also called 'kampung' durians meaning although they are not considered heirlooms but these fruits are produced from matured trees which grew naturally from seed. The reason I would not call these kampung durians as heirlooms is because their trees grew from seeds which is a result of sexual reproduction between a male gene and a female gene either from the same tree or genes (male or female) from other kampung durian trees. Kampung durians are inconsistent in taste and other characteristics. They have large seeds with thin flesh and mostly are pale cream or even off-white flesh coloration. Some of it have watery flesh as well. Because of this, kampung durians have lower commercial value since buying kampung durians is like rolling the dice. It doesn't have a standard quality or fruit expectation and even the sellers don't really know what to expect until he opens the fruit for the buyer to see. The clone durians come from trees which were grafted. These durians have much more commercial value, better tasting, flesh coloration and overall consistency in terms of flavor. In Malaysia, clone durians are the ones with registered names starting with the word 'D' followed by a number, eg; D197, D99 or D168. It has to be noted nonetheless, that some clones doesn't have a 'D' name. This is by virtue of it not being registered with the Department of Agriculture. Clone durians comes from trees that were originally produced from a scion of a known clone and grafted with a rootstock of a native or kampung durian. This is an asexual reproduction hence the word 'çlone' durians. The reason of having a native/kampung rootstock is that these rootstocks have better root disease resistance, drought tolerant and better adaptability to local soil conditions. It has to be noted, while native/kampung rootstock are the normal practice but the best rootstock is still the seedling from a jungle durian. The jungle durians are considered fairly heirloom. Its tree are quite hard to find especially in Peninsular Malaysia although it still exist in deeper areas of the forests. The reason behind this is due to forest clearing to make way for commercial crops or even clone durian plantations. Jungle durians have an unpleasant taste, some could have nauseating effect if consumed in large amounts. Physical appearance wise, it has longer and winding thorns.
OK, I won't give an open ended answer for this like "Plant what you like to eat" kind of answer. In Malaysia, if we look at the commercial aspect the highest prices that a durian can fetch in the market place are the D197 Musang King and the D200 Duri Hitam. Ideally farmers and growers should plant the majority of their saplings with this type of clones while adding 25% - 30% remaining with other clones. Prices of durians does fluctuate from year to year but in general, these 2 clones will stay at the high end of the price band. As for the future, nobody knows. Research shows that adding 25% - 30% of other clones especially clones that has a high flower blooms such as the D99 a.k.a Kop Kecil will stimulate higher fruit sets on the main planted clone. In this example, although the D99 clone are not among the sought after clones with high demand but it still has market value and could be sold as a not so common clone fruit. Decision based on highest market prices are common place but a durian grower would also decide based on selecting a sought after, good clone with medium market prices which makes it affordable to the general public. An example of this is the D160 or also famously know as Musang Queen or Tekka. Prices of D160 are above average and still commands a following among durian enthusiast. Export market influence is still low for the Musang Queen but local demand for this clone is strong at the time of writing. Another example of a 2nd tier durian clone is the evergreen demand D24 a.k.a Bukit Merah. Registered before Malaysia's independence, the D24 had always been among the top clones and once held market dominance before the introduction of the D197 and D200. This clone still retains its commercial value albeit at a slight tone-down pricing. The D24 is considered as the clone that everyone knows and grew up with. With the extensive removal or cutting down of matured D24 trees mostly in Pahang and Perak where it was originally cultivated the most, in part to make way for D197 and D200 cutivation, D24 saplings are now back in demand and are being replanted in a number of places. It will find back its former glory for sure. Rare Durian Clone Selective Planting I know of some nursery owner and a durian grower which plant rare clone types exclusively at their farm. The definition of 'rare' could be a combination of hard to get unregistered cultivars (most of it are cultivars from Penang) or cultivars from Thailand and Indonesia. These cultivars does not necessarily commands a high market price and public demand nor they have good taste but the drive behind why farm owners grow these cultivars is because of its rarity, to establish a personal family collection (heritage), unique physical appearance, conservation efforts or as a scion harvesting source for nursery owners intending to sell saplings of these cultivars. These rare durian cultivars could be read in detail here.