| A possibly significant observation is the fact that Ae. ligustica,
the form widely distributed among plant breeders and geneticists as Ae.
speltoides, tends to occur where typical Ae. speltoides grows
intermixed with Triticum boeoticum. Frequent spikes of the ligustica
form in mixed populations were observed to be sterile. Sterility is also
very high in the material distributed among plant breeders. The A genome of polyploid wheats presumably was contributed by the wild diploid species. Triticum boeoticum or its cultivated derivative, T. monococcum. On cytological as well as electrophoretic criteria, however, the monococcum genome is quite different from the A genome of the polyploid species. The extensive collection of T. boeoticum obtained in the present excursion will provide evidence regarding existing variability in the A genome which may provide an explanation of the observed discrepancy. The sympatric occurrence of T. boeoticum (AA) and Ae. speltoides (BB) throughout south-central Turkey suggests that that is also a plausible area for the origin of tetraploid (AABB) wheats. However, the wild tetraploid, T. dicoccoides was not observed there. Contrary to expectation, Ae. squarrosa (DD) the presumed donor of the D genome to hexaploid wheats (AABBDD) was not observed in the areas of eastern Turkey visited by the expedition. This observation strengthens the belief that the hexaploid wheats most probably originated in Iran. Ae. cylindrica which carries the D genome was collected in several areas of eastern Turkey, and as far west as Ankara. The genome composition of polyploid species in Aegilops has been worked out in considerable detail from cytological evidence. This work together with the present collection of Aegilops species is invaluable for testing the ultimate usefulness of the electrophoretic method for analyzing polyploid series. Many local varities of wheat in Turkey are threatened with extinction by the increasing cultivation of widely adapted introduced vaieties. To guard against the eventual loss of valuable genetic material, collections were made of various plant types in fields of T. durum, T. compactum and T. aestivum. Further efforts, however, should be made to preserve this valuable breeding material. Likewise collections of various plant types were made in fields of cultivated rye, and in wild populations of Secale which occurred in abundance in the Dogubayazit-Kars area. Quite apart from meeting the needs of studies now in progress the present collection will be available to all research workers. At present it is held at the Swedish Seed Association, Svalof, Sweden until final identification has been completed. The accessions with collection data will be catalogued at the Crop Research and Introduction Centre, Izmir. Responsibility for seed increase is assumed by the senior author. |
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