Viewing post #3010967 by Strigeidida

admmad said:In diploids each chromosome of the chromosome pairs has only one choice for pairing at meiosis. So they pair symmetrically at meiosis and there are 11 sets in daylilies. In tetraploids each chromosome has a number of possibilities when it comes to pairing/aligning. One set of four can align as a quadruplet or it can align as a triplet with one "unpaired" or it can align as two pairs. When the chromosomes separate, singles can be lost completely and quadruplets may separate as three and one rather than two and two. Each set of four does this independently of how the other sets align. The end result is that in diploids basically 100% of the gametes have a balanced chromosome set of one chromosome for each of the 11 sets - they have 11 chromosomes. In tetraploids the gametes do not necessarily have 22 chromosomes and even when the number is 22 it may not be two of each of the 11 sets. Unbalanced gametes are not necessarily viable and the seeds created by viable unbalanced gametes are not necessarily viable. The situation in triploids is much worse in terms of balanced chromosome sets in gametes. In hexaploids the alignments would be more variable and the viable gametes fewer.

That's the best explanation of limited fertility in tetraploids I've heard yet. I've found at least two tets that show a goodly amount of fertility, judging by the number of capsules carried to fruition.

Thank you for the information you have given us so far. It's better than chocolate. I love it.