Correns was a student of Karl Nägeli, a renowned botanist with whom Mendel corresponded about his work with peas, and who subsequently engaged in a brief exchange of letters concerning reproducibility of the results in another species (Hieracium).

After completing his thesis, Correns became a tutor at the University of Tübingen and in 1913 he became the first director of the newly founded Kaiser Wilhelm Institute for Biology in Berlin-Dahlem.

He also discovered cytoplasmic inheritance, an important extension of Mendel's theories, which demonstrated the existence of extra-chromosomal factors on phenotype.

This non-Mendelian inheritance pattern was later traced to a gene named iojap which codes for a small protein required for proper assembly of the chloroplast ribosome.

The progeny could have functional copies of iojap, but since the chloroplasts come exclusively from the mother in most angiosperms, they would have been inactivated in the previous generation, and so will give white plants.