Chromosome Behavior in Fertile Triploid Aster Hybrids

HE sterility of triploids and other unbalanced polyploids is generally con-T ceded to be a consequence of irregularities in the distribution of univalents and multivalents at meiosis. Occasional viable gametes are produced, however, because of nonrandom orientation and segregation of chromosome associations. Thus, SATINA and BLAKESLEE (1937a, b) found a higher frequency of n and 2n chromosome numbers in gametes produced by triploid Datura than was expected on the basis of random orientation of trivalents.