Mendel studied seven contrasting characters for his breeding experiment with Pisum sativum, which of the following character did he not use?

The correct option is C Leaf shape

• Mendel chose seven pairs of contrasting traits, namely plant height, flower position, pod colour, pod shape, seed colour, seed shape and flower colour. The axial flower position was recessive to the terminal position.
• Green seed and wrinkled seeds were recessive to yellow and round seeds; yellow, constricted pods were recessive to green and full pods.
• Dwarf stem with white flowers was recessive to a tall stem with violet flowers. He did not study the inheritance of leaf shape.

Thus, the correct answer is option C.