when a cross produces offspring that do not breed true (i.e., the offspring do not all resemble their parents) we say the parents have genes that segregate or are hybrid. Just as a strain can breed true for one or more traits, it can also segregate for one or more traits; this is often seen. For example, consider a cross where some of the offspring have webbed leaves and some have normal compound-pinnate leaves
this is from a large post in the grow FAQ's in advanced techniques ,it means different genes can be expressed showing diff traits they all wont look alike at times or finish at the same time