ill try to explain it tho i dont know to much someone will know more. Lets say someone wants a hatchling to have a lot of carrot tail then he will take the 2 adults with the most carrot tail and breed them. If they want bright albinos then they take the brightest albinos and breed them.
im pretty sure thats what it means. Soon someone will post somemore info im sure
That pretty much sums it up, Marcia! But just to clarify it a little more for you, line breeding means taking leos with the best traits and 'inbreeding' them to get the best babies. Orange geckos will produce a few geckos that are a little more orange... breeding them back to the brighter parent, or to eachother, will give you MORE orange offspring etc. Any trait that acts like a polygenetic trait can be "line bred" or 'inbred' to produce ... well, 'better' geckos!