Hit the Mendelian genetics nail right on the head. Two IBL parents (homozygous, same alleles) will create an F1 generation that is completely uniform. It is my understanding that this true F1 will show amazing hybrid vigor. Two, or even one non-IBL parent (heterozygous, different alleles) and your phenotype expression is all over the place.Well bred lines will be pretty similar output in terms of plants. Most crosses you see today are polyhybrids with no stability. Take two IBL's and cross them and you will get stability and usually a nice quality plant too (assuming the qualities show that you wanted to show).
Good eye. The middle one Is the only one I didn't top. These beans are from Sensiseeds..the one in the middle is going to have a different structure, it looks to have more of a single cola than the bushy look of the rest. but you have to love the way they are all very close so far. who`s genetics are they?