抄録
The chiasma behaviour is quantitatively analysed in diploid and triploid Hyacinthus. It is shown that, as in Tulipa, while the chiasma frequency in the triploid is greater than in the diploid, and the interference between successive chiasmata is less, the length-chiasma frequency relationship is essentially similar in both.
The conception of “pairing blocks” at zygotene is applied to Hyacinthus and the conditions controlling the number and extent of the “pairing blocks” are discussed. It is shown that these conditions result in the medium chromosomes having a higher number of pairing blocks than either the short or the long chromosomes.
