More than 160 years after Gregor Mendel laid the foundations of modern genetics using garden peas, scientists from Shenzhen have finally decoded the complete genetic basis of the seven traits he studied, thereby resolving a question that has puzzled researchers for generations.

The breakthrough, led by Dr. Cheng Shifeng of the Agricultural Genomics Institute at Shenzhen (AGIS), part of the Chinese Academy of Agricultural Sciences, identified the final three genes that had eluded scientists since Mendel’s 1865 experiments. The findings were published in the journal Nature, with Nature and Science both highlighting the work as a milestone in plant genetics.

While four of Mendel’s trait pairs — such as seed shape and plant height — were genetically mapped over the past century, the remaining three (pod color, pod shape, and flower position) remained unsolved. Using whole-genome sequencing, bioinformatics, and functional molecular biology, the AGIS-led team analyzed nearly 700 pea varieties during their research conducted in Dapeng to trace the full genetic architecture behind all seven of Mendel’s classic traits.

The study found several determinants. Pod color (green vs. yellow) is governed by the regulation of chlorophyll biosynthesis genes. Pod shape (inflated vs. constricted) is controlled by two developmental genes that can act independently or together. Lastly, flower position is influenced by a gene encoding a co-receptor kinase, whose mutations subtly delay or mask trait expression.

In the process, the team also produced the most comprehensive haplotype and trait variation map of peas to date, covering 72 key agronomic traits. This map will be an invaluable tool for molecular breeding and crop improvement.