Classic cubensis isolates

Before the designer crosses, there were the landraces: lines collected from a region and kept more or less as found. Cambodian, Ecuador, Thai and the rest are named for where the original collection came from, and they are the genetic base that almost every modern cross traces back to.

They remain the most useful reference material in the species precisely because they are well characterised and widely held. If you want to check a technique or compare a measurement against the published literature, a classic line gives you something thousands of other people have also looked at.

Landraces and early isolates

A landrace is a population adapted to a particular place and collected from it, rather than bred for a character. Cambodian, Ecuador and Thai are landraces in that sense.

B+, Mckennaii and JMF are early isolates rather than landraces: lines taken out of a population and stabilised. The distinction is worth knowing because it tells you how much variation to expect on the slide.