Relationship in annual species of Medicago. II. Interspecific crosses between M. tornato (L.) Mill. and M. littoralis Rhode.

Abstract

Six hybrids were obtained from 212 reciprocal crosses between M. littoralis Rhode and M. tornata (L.) Mill. The hybrids were chlorophyll-deficient in the early seedling stage but later development was normal although growth was retarded. The morphological characteristics were intermediate between those of the parents. Pollen fertility and seed set amounted to 7 and 10% respectively. Meiotic irregularities indicate that M. littoralis is differentiated from M. tornata by at least one translocation. The contribution of the structural changes in the chromosomes accounted for about 60% of the observed pollen sterility.