Aspartate aminotransferase and alcohol dehydrogenase isoenzymes: Intraspecific differentiation inAegilops tauschii and the origin of the D genome polyploids in the wheat group

Polyacrylamide gel electrophoresis of aspartate aminotransferase (AAT, EC 2.6.1.1) and alcohol dehydrogenase (ADH, EC 1.1.1.1) isoenzymes reveals intraspecific differentiation ofAegilops tauschii Coss. (=Ae. squarrosa auct., non L.) into two groups of biotypes which essentially correspond to its two morphological subspecies, subsp.tauschii and subsp.strangulata (Eig)Tzvel. Subsp.tauschii which is characterized by a slower electromorph of AAT-B and a faster electromorph of ADH-A is identified as the contributor of its D genome to the tetraploidAe. cylindricaHost and the hexaploidAe. crassaBoiss. subsp.crassa. Subsp.strangulata, being distinguished by a faster electromorph of AAT-B and a slower electromorph of ADH-A, has contributed the D genome to the hexaploid bread wheats (Triticum aestivum L. emend.Thell.), the tetraploidsAe. crassa subsp.macrathera (Boiss.)Zhuk. andAe. ventricosaTausch, and the hexaploidAe. juvenalis (Thell.)Eig. —Aegilops comosaSibth. etSm. s. lat. is questioned as the contributor of the M genome toAe. crassa. Furthermore, the S genome diploidsAe. bicornis (Forsk.)Jaub. & Spach,Ae. longissimaSchweinf. & Muschl. s. lat. andAe. searsiiFeldman & Kislev are all considered unsuitable as the wheat B genome donors on the basis of the AAT isoenzyme data.