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Ae. caudata L. is an annual, diploid species distributed over the eastern Mediterranean. Morphologically, it is divided into two varieties, var. typica and var. polyathera Boiss. In the present work, two series of crossing experiments were carried out. Firstly, reciprocal crosses between the two varieties collected from sympatric populations were made. All F1 hybrids showed normal fertility. Secondly, crosses between accessions collected from different geographical regions were made. F1 hybrids from the crosses between most Aegean accessions and the accession from Syria (Tester A) or the accession from northern Turkey (Tester B) showed complete sterility. However, those from the crosses between the Aegean accessions and the accession from Olympia in Greece (Tester D) showed normal fertility. Contrary to this, F1 hybrids from crosses between the accession from northern Iraq and those from Syria and northern Turkey showed high fertility, while complete sterility was observed in hybrids between the Iraqi accession and the accessions from Greece and northwestern Turkey (Testers D and C). Accordingly, it is concluded that the intraspecific hybrid sterility in Ae. caudata is not a characteristic of intervarietal hybrids but is due to geographical differentiation: The factors responsible for genetic differentiation in Ae. caudata causing intraspecific hybrid sterility are not correlated with morphology but with geography. |
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