I any advice one what characteristics to pick when picking a seedling yo plant. One of my trees died and Im outside of durians optimal range so I’ve tried grafted trees and they jusy can’t adapt. I planted maybe 30 seeds from fruits I ate last year and a good portion of them died over the winter which weeded out the less cold tolerant ones.
How do I pick which one to plant in the ground? Should I be going for the tallest most vigorous one or a smaller more well formed one. I was thinking a smaller one that looks a bit healthy as it is just in a back yard I don’t partially want a giant tree.
Keep in mind in the photo some are just in a pot that’s much taller so it makes the height difference seem much bigger than it actually is. Only re potted this week and tan out of potting mix
All of the durian seedlings will become large eventually so if you don't want a big tree you have to prune it multiple times per year or not plant it at all. There aren't any natural dwarf durian available that I know of.
And if you think you have one it is probably more like a sick tree or malnourished tree.
If durian tree's doesn't grow more then 1m per year after the 1st year there is something wrong. And fruit would most likely be 15 years in the future.
If the trunk is less then 6cm diameter after 3 years, growth rate is not what it can be and it's not gonna fruit in between 5 to 10 years for a seedling. IMOE.
The most vigorous seedlings you have probably doesn't have much genetic variability unless you have sown seeds from 30 different mother tree's with themself quite a lot of genetic variability.
It's more likely the soil in the pot (even if you have the same blend there will be differences), herbivores, position, water and seed size have determined which are your biggest and smallest seedlings now.
If you want to try and gain some cold sensitivity you probably need a sample number higher then 1000. And that would have to be with lot's of different sources seeds.
The most cold sensitive durian species known is durio kinabaluensis but I do not know of anyone in AU having it. And you would have to cross that one with Durio zibethinus and plant heaps of those seeds if you want a fruit that resembles common durian. That project would take around 20 years. I am gonna start it as soon I get the kinabaluensis.
You would most likely have to plant a durian close to a wall that receives sun as to have something radiating heat at night so that you have higher chance for survival long-term.
You would probably do good with installing a big proper galv steel enclosure with shade mesh to protect from wind and mid summer sun during dry days.