In 2010, after a long anatomical study, they performed DNA barcoding on a slice of the snack and found it to match that of agave’s by 89 percent [narrowed] down to Agave Sisalana. [...] Next, they chopped off its leaves and there it was: the fat, white, watery trunk familiar to millions of Indians from food carts. They ate a slice from it, and it was tasteless and crunchy just like Ram Kand. The findings were published inCurrent Science the following year.
When I look at the Jicama plant it doesn't even remotely look like an Agave. It certainly doesn't seem to me that DNA barcoding would yield an 89% match with Agave Sisalana.
I'm not sure that I get the point of your analogy.
To be clear, I'm saying that genetic match supersedes any list of superficial attributes to determine identity. If it's established that X and Y are an 89% DNA match, even though X tastes and looks like Z, the fact that Y and Z belong in distant genetic branches should be enough to dismiss X as a possible Z.
When I look at the Jicama plant it doesn't even remotely look like an Agave. It certainly doesn't seem to me that DNA barcoding would yield an 89% match with Agave Sisalana.