Why are polyploids with even multiples of the euploid chromo

Why are polyploids with even multiples of the euploid chromosome set usually more sexually fertile than polyploids with odd multiples of the euploid chromosome set?

Solution

the gametes formed by a process called meiosis. during meiosis, the pairing takes place between two chromosome of each type(one from mother and one from father) in euploid organism. these paired homologs can segregate to opposite poles during cell division but in cells with odd chromosome number, the chromosome remains unpaired which results in non functional gametes(aneuploids). these gametes do not give rise to a viable offspring.