Further evidence for natural hybridization between tetraploid species of Aegilops section Pleionathera
Evolution. NY, 62-74
Natural hydridization and gene flow take place among most of the tetraploid spp. of Aegilops sect. Pleionathera. In Israel, variation patterns in mixed populations of A. variabilis, A. biuncialia, and A. ovata and in mixed populations of A. variabilis and A. triuncialis showed that intermediates and many highly introgressed types occur. In Turkey and Greece less detailed field observations confirmed on a wider scale the common occurrence of natural hybridization among 5 tetraploid members of the sect. Pleionathera. The tendency of these tetraploid spp. to form polymorphic mixed populations consisting of several spp. increases the frequency of the contact among them and thus facilitates further hybridization. Moreover, the tetraploids which comprise 1 mixed population have 1 genome in common that serves as a cytological buffer in the interspecific hybrids and makes the gene exchange possible, while the 2nd genomes differ and can recombine. The great adaptability thereby achieved constitutes an evolutionary advantage.