The major cause of Mendel’s success was his clear and accurate mathematical analysis of the causes of failure of his antecedent workers. Mendel was able to draw laws or principles. His success can be attributed to the following reasons :
Working Method :

1. Mendel studied only one character at a time. When the nature of each character was determined, he studied two characters together and then three.
2. Mendel carried out experiments up to the seconed and third generations.
3. For study, Mendel selected only two clearly contrasting forms of each character which could easily be identified separately from each other.
4. His perfect knowledge of mathematics enabled him to understand the significance of ratio of contrasting characters and to explain laws clearly.
5. He maintained the statistical records of all the experiments and analysed them carefully.
6. Cross - breeding was done between the parents of pure line.
7. The pure lines of parent plants were ascertained by a series of self-crossing tests between progeny of each successive generation.

In spite of all these, Mendel was undoubtedly lucky because :

• None of the characters, selected by him was quantitative.
• Each character was controlled by one factor (now called gene).
• None of the seven characters on which he experimented shown linkage.