In 1866, he published his results and ideas in fourth volume of “Proceedings of Natural History Society of Brunn”. The title of the paper was “Experiments on Plant Hybridisation”.
Mendel selected 14 true-breeding pea plant varieties or 7 Pairs of contrasting trait.
A true breeding line is one that, having undergone continuous self-pollination, shows the stable trait inheritance and expression for several generations.
Variation is the degree by which progeny differs from their parents.