Wild tetraploid wheats from Northern Iraq cytogenetically closely related to each other¹⁾

Masatake TANAKA and Taihachi KAWAHARA

Plant Germ-plasm Institute, Faculty of Agriculture, Kyoto University, Kyoto, Japan

In 1970, the members of the Botanical Expedition of Kyoto University to the Northern Highlands of Mesopotamia found out a densely mixed stand of Triticum dicoccoides and T. araraticum near Amadiyah, Iraq (TANAKA and ISHII 1973). Samples belonging to each species were morphologically similar but could be clearly distinguished by hairiness of leaf surface ; araraticum was hairy but dicoccoides was glabrous.

Materials used were two strains of dicoccoides, 8821A and 8821C, and four of araraticum, 8819, 8821B, 8822, and 8827. All were collected at a site 15.3 km ENE from Dohuk to Amadiyah, Iraq (alt. 780m). These strains were crossed to each other and chromosome associations of seven interspecific hybrids were observed (Table 1). All F₁ hybrids grown in the experimental field set no seeds when bagged.

Chromosome associations of F₁ hybrids presented in Table 1 clearly show that the two wild tetraploid wheats collected at this site are cytogenetically more closely related to each other than those reported so far. For example, RAWAL and HARLAN (1975) reported 5.2-6.0 univalents per cell in chromosome associations of F₁ hybrids between four Turkish collections of dicoccoides and timopheevi. Of these seven hybrids, 8821A x 8821B gave extremely low frequency of univalents at meiosis. No univalent was found in 38 per cent of the PMCs. A hybrid 8821A x 8822 also showed very good pairing and 20 per cent of the PMCs formed no univalent.

Morphological similarity of the two wild tetraploid wheats in Northeast Iraq and Western Iran was already pointed out by DAGAN and ZOHARY (1970) and TANAKA and ISHII (1973). The results of this study indicate that they have also close cytogenetical relationships to each other. Obviously, this similarity is very important in studying the evolution of tetraploid wheats and needs further analysis. A more detailed account and possible implications of this study will be published elsewhere.

Literature Cited

DAGAN, J., and D. ZOHARY 1970. Wild tetraploid wheats from West Iran cytogenetically identical with Israeli T. dicoccoides. Wheat Inform. Serv. 31: 15-17.

RAWAL, K. and J. R. HARLAN 1975. Cytogenetic analysis of wild emmer populations from Turkey and Israel. Euphytica 24: 407-411.

TANAKA. M. and H. ISHII 1973. Cytogenetical evidence on the speciation of wild tetraploid wheats collected in Iraq, Turkey and Iran. Proc. 4th Intern. Wheat Genetics Symp. 115-121