Mashua: Tetraploid Variability

Twelve sets of three tubers each of seedlings out of Blanca mashua. Each is a little bit different, with mostly white or light yellow skin and various shades of red or purple eyes.

The domesticated varieties of mashua (Tropaeolum tuberosum) are tetraploid, meaning that they have four copies of each chromosome.  This allows the plant to carry twice the genetic diversity of a diploid organism (like most animals and many plants).  Balanced against that, mashua is most likely an autoploid, meaning that it became tetraploid by doubling its […]

Potato: A Ploidy Primer

A micrograph showing two potato guard cells comprising a stomatum. The chloroplasts in each guard cell are marked. Six are present in one and seven in the other.

Introduction   How Seeds are Formed   Domesticated and Wild Potatoes   Ploidy   Monoploid and Haploid Numbers   Haploids Interactions of Ploidy in Crosses   Unreduced (2n) Gametes   Endosperm Ratio   Endosperm Balance Number   A Final Note on Probability Determining Ploidy   Morphological Evalutation   Guard Cell Counts   Chromosome Counts More […]