| Origin of Triticum monococcum L.
Harcharan S. DHALIWAL* Department of Plant Sciences, University of California Riverside, Ca. 92502, USA The cultivated einkorn Triticum monococcum L. is commonly believed to have been domesticated from wild einkorn T. boeoticum BOISS. em SCHIEM. They differ from each other largely with respect to fragility of the rachis. In T. boeotium individual spikelets disarticulate at maturity. According to HALBAEK (1966) West Central Anatolia was the primary center of conscious selection of T. monococcum. Various sites of excavations such as Ali KOSH (Iran), Catal HUYUK and HACILAR (Turkey), from where specimens of T. monococcum have been recovered (HALBAEK 1959, 1966), are within the general area of distribution of T. boeoticum (HARLAN and ZOHARY 1966; JOHNSON 1975). Recently another wild diploid wheat T. urartu Tum. - heretofore considered as an obscure Armenian endemic - is found distributed aboundantly in South Eastern Turkey and Lebanon and sporadically in Northern Iraq and Western Iran (JOHNSON 1975). The distribution of T. urartu covers the probable area of domestication of T. monococcum. Triticum urartu is reproductively isolated from T. boeoticum throughout the range of their sympatric distribution (JOHNSON and DHALIWAL 1976). Triticum monococcum, therefore, could have been domesticated from T. urartu or T. boeoticum or both at one or at several places of their wide sympatric distribution. Morphological and cytological evidence reported here suggests that T. monococcum was presumably domesticated only once from a population of T. boeoticum with a limited introgression from T. urartu. Materials and Methods The T. urartu x T. monococcum F1 hybrids and the reciprocal crosses were made between 14 accessions of T. urartu and 12 accessions of T. monococcum to cover the variability in the two species. A few T. monococcum x T. boeoticum hybrids including their reciprocals were also made. Observations on size, appearance and germination of the F1 hybrid seeds were made as reported by JOHNSON and DHALIWAL (1976) for T. boeoticum x T. urartu hybrids. Sterile boeoticum (female) x urartu (male) hybrids including the reciprocal crosses (JOHNSON and DHALIWAL 1976) were backcrossed with T. boeoticum and T. urartu to obtain first backcross (BCI) progenies (Table 2). Morphological attributes (Table 3) were recorded from herbarium specimens and field growing plants of several accessions of each species. Results and Discussion Hybrids involving T. boeoticum and T. urartu gave germinable seeds only when T. boeoticum was used as the female parent (Table 1). The reciprocal crosses with T. urartu as the female parent gave completely shrivelled and non-germinable seeds (JOHNSON and DHALIWAL 1976). The F1 hybrid seeds from reciprocal crosses involving T. boeoticum and T. monococcum, although differed from each other with respect to size, were fully developed and germinable (Table 1) supporting the earlier view that T. monococcum was just a domesticated type of T. boeoticum. The monococcum (female) x urartu (male) F1 hybrid seeds were small, plump and completely germinable like that of the boeoticum (female) x urartu (male) hybrids. However, the urartu (female) x monococcum (male) hybrids gave only partially shrivelled and germinable seeds (Table 1) unlike that of the urartu (female) x boeoticum (male) hybrids. Triticum monococcum, therefore, differs from T. boeoticum in their reciprocal crosses with T. urartu. Only partial shrivelling and good germination of urartu (female) x monococcum (male) hybrid seeds suggests that T. monococcum might have been domesticated from a T. boeoticum population with introgression from T. urartu. |
| * Present address: Friedrich Miescher-Institut, P.O. Box 273, CH-4002 Basel, Switzerland. |
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