Further studies of linkage in the sweet pea

Summary

Extensive data are given on the crossing of eighteen pairs of characters inLathyrus odoratus. As a result these eighteen pairs arrange themselves.into five linkage groups and two unassociated characters. Since the haploid number of the chromosomes is seven, the data are in accordance with the chromosome theory. Attention is drawn to the frequency of deficiency of recessive characters in theF ₂ generation, and it is suggested that the degree of deficiency may possibly be correlated with the age of the recessive mutation in question, the youngest mutations showing the most marked deficiencies, andvice versa.