| I. Research Notes Morphological characters and meiotic associations in a T. aestivum L. var. erythroleucon Korn. x Ae. biuncialis Vis. hybrid Murat OZGEN University of Ankara, Faculty of Agriculture Department of Field Crops, Ankara, Turkey In order to transfer the genes for resistance to stripe rust (Puccinia striiformis West.) of wheat from Ae. biuncialis (2n=28) to T. aestivum (2n=42) an attemp was made to cross these two species during the spring of 1980. Emasculating and crossing techniques were detailed in the previous study of OZGEN (1983 a). 18 ears with 457 florets were polinated with pollen of Ae. biuncialis and 114 seeds were obtained. Control of chromosome numbers was made by examining root tips under the microscope and the hybrids were found to be pentapoloid (2n=35) (Fig. 1). All seeds of the hybrids germinated and 114 F1 plants were obtained. However, only 51 of those plants were able to head. The F1 plants were intermediate with respect to most of the morphological characters, but dominance was observed for some of the characters. Although the hybrid heads looked more like wheat than Ae. biuncialis, they carried some characteristics of the male parent (Fig. 2). Some characteristics of the parents and hybrids are given in Table 1. Hybrid plants as predicted by MAAN (1975), were pollen sterile with nondehiscent anthers. Only 2 seeds were obtained from 2265 heads from 51 F1 plants, with free pollination. Meiotic behaviour of the F1 hybrids was analyzed at the first metaphase stage and chromosome pairing was observed (Table 2 and 3). This showed that the number of bivalents varied between zero to twelve and most of them were of the rod type, but there were some ring types too (Fig. 3). As it is known, chromosome pairing in hybrid shows the level of relationship between parents (DEWEY 1982). Chromosome pairing in the F1 hybrids of T. aestivum x Ae. biuncialis were found to be higher than for T. durum x Ae. umbellulata's F1 hybrids (OZGEN 1983 b). As indicated by this study, it appears easier to transfer genes from Ae. biuncialis to T. aestivum than to transfer genes from Ae. umbellulata to T. durum. Literature Cited DEWEY, D.R. 1982. Geonomic and phylogenetic relationships among North American perannial Triticeae. Ed. J.R. Estes, Univ. of Oklahoma Press. 51-87. MAAN, S.S. 1975. Cytoplasmic variability in Triticinae. Wheat Inform. Serv. 40 : 1-6. OZGEN, M. 1983 a. Hybrid seed set in wheat x Aegilops crosses. Wheat Inform. Serv. 56 : 9-11. OZGEN, M. 1983 b. Morphological characters and meitotic associations in a T. durum Desf. var. hodeiforme Korn. x Ae. umbellulata Zhuk. hybrid. Wheat Inform. Serv. 57 : 1-3. |