| Haploid Aegilops caudata V. CHAPMAN and R. RILEY Plant Breeding Institute, Cambridge, England Only two haploid plants have previously been reported in the genus Aegilops. These were in the species Ae. ovata (2n = 28) and Ae. longissima (2n = 14) and both occurred in progenies resulting from pollination of the Aegilops forms with the pollen of Triticum species. The instance reported here is concerned with a haploid individual of Ae. caudata (2 = 14). In a population of Ae. caudata grown in the field at Cambridge one plant had gaping glumes and non - dehiscent anthers at flowering. Cytological preparations were made from root - tip and anther squashes and these showed the plant to have only seven chromosomes and therefore to be haploid. At first metaphase of meiosis all the chromosomes were univalents in most cells, but one bivalent was occasionally formed (Table 1). The low frequency of bivalents is similar to those reported in haploids of other diploid species in Aegilops and Triticum and it can be interpreted to mean that there is little duplication of genetic material within the genome of Ae. caudata. This information may be of value to those concerned with the interpretation of meiotic chromosome pairing, in hybrids involving Ae. caudata, in genome analysis and evolutionary studies. |