| Triticum dimococcum, a new amphidiploid from
the hybrid
Triticum dicoccum x monococcum Elisabeth SCHIEMANN and Gunter STAUDT Forschungsstelle fur Geschichte der Kulturpflanzen in der Max-Planck-Gesellschaft, Berlin-Dahlem, Germany The hypothesis of F. and K. Bertsch, published in 1939, that Triticum compactum arose in Middle Europe (viz. in Schwaben) as a hybrid from T. monococcum x T. dicoccum, cannot be maintained for cytological reasons (as shown by Schiemann in 1940) since it does not explain the occurrence of genome D in hexaploid wheats; nor can it be maintained for morphological reasons. Though since 1944 the provenance of the D-genome from Aegilops squarrosa has been verified by McFadden & Sears and Kihara, K. Bertsch, basing on prehistoric results, still in 1949 and 1950 holds his hypothesis which had been explicitly refuted by Lang in 1948. It is of interest, therefore, to produce the postulated 6x amphidiploid experimentally and compare it with the natural 6x wheats. We have performed the synthesis of the amphidiploid T. dicoccum x T. monococcum-we call it T. dimococcum-and analyzed the morphology of the 6x hybrid and its progeny, which should be of interest regarding the morphological variability in the hexaploid wheats. The parents are: T. monococcum (Einkorn) from Wurttemberg (South Germany) T. 482, and T. dicoccum (Emmer) from Oerlikon (Switzerland) T. 551. The two species are known to cross with difficulty. The cross monococcum x dicoccum gave 25 grains=4.6% out of 514 pollinated flowers and the reciprocal cross 20 grains=1.8% out of 1072 pollinated flowers. Colchicine treatment-0.025% for 2, 6, or 12 hours-restulted in 20 hybrid plants. They equalled morphologically in both directions; only 2 plants with dicoccum as mother proved partly amphidiploid. The grains from 1953 were planted as C2 in 1954 and the plants were analyzed. |
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