Abstract
Chiasma frequencies obtained in Seeale cereale and Vicia faba grown in Japan, were higher than those obtained for the same species grown in a greenhouse at the Arnold Arboretum. There is some evidence that such differentes may be attributed to differentes in environmental conditions, although inherent varietal differentes within species doubtless occur. The variations found in Tradescantia show that both factors may be operative in a single species. The variations in environmental factors which influence chiasma formation may occur in nature.
No interchromosomal correlation was found in comparing the chiasma frequency of the long “M” chromosome with the chiasma frequency of the five short chromosomes of Vicia faber.
