Polyploids are organisms with three or more complete sets of chromosomes. If a diploid organism is 2n, then a triploid is 3n, a tetraploid is 4n, and so on.
All major groups of seed plants have some polyploid members. Plant polyploids are larger than plants with 2n chromosome number. Plant polyploids with even chromosome numbers (e.g., 4n) can usually produce pollen and seeds. Plant polyploids with odd chromosome numbers (e.g., 5n) are nearly always sterile.
18. If a diploid plant and a tetraploid plant, each capable of normal meiosis, were crossed, the chromosome number in their offspring would be