| I. Research Notes Morphological characters and meiotic associations In a T. durum Desf. var. hordeiforme Korn. x Ae. umbellulata Zhuk. hybrid Murat OZGEN University of Ankara, Faculty of Agriculture Deprtment of Field Crops, Ankara, Turkey In order to transfer the genes of resistance to stripe rust (Puccinia striiformis West.) of Ae. umbellulata (2n=14) to T. durum var. hordeiforme (2n=28) an attempt was made to cross these two species. As far as we know the first attempt to cross wheat species to Ae. umbellulata was made by SEARS (1956). However in that study T. aestivum was used as the female parent in the cross. In this study a variety of T. durum var. hordeiforme entries, susceptible to stripe rust, was crossed to resistant Ae. umbellulata entries in the spring of 1980, under field condition. 30 ears with 886 florets were pollinated with pollen of Ae. umbellulata and 99 seeds were obtained. Emasculating and crossing techniques were detailed in the previous study (OZGEN 1988). Control of chromosome numbers under microscope at root tips has proven that these hybrids are tripolids (2n=21) (Fig. 1). The 50 F1 plants obtained from the hybrid seeds were intermediate regarding most of the morphological characters, although some characters of the parents were dominant. The ears of the hybrid plants looked more like wheat than Ae. umbellulata (Fig. 2). Some characteristics of the parents and hybrids are shown in Table 1. Hybrid plants, as predicted by MAAN (1975), were pollen sterile with non dehiscent anthers. Only 121 seeds were obtained from 1546 ears with free pollination. Meiotic behaviour of the F1 hybrids was analysed at the first metaphase stage and chromosome pairing behaviour was observed (Table 2 and 3). This showed that the number of bivalents varied between zero and eight and most of them were of the rod type, some of them looked like the ring type (Fig. 3). As pointed out by DEWEY (1982), chromosome pairing shows the level of relationship between parents. In this study, chromosome pairing in F1 hybrids of T. durum var. hordeiforme x Ae. umbellulata showed that it is difficult to transfer genes from Ae. umbellulata to T. durum var. hordeiforme. Literature Cited DEWEY, D.R. 1982. Genomic and phylogenetic relationships among North American perennial 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. Hybrid seed set in wheat x Aegilops crosses. Wheat Inform. Serv. 56: 9-11. SEARS, E.R. 1956. The transfer of leaf-rust resistance from Aegilops umbellulata to wheat. Brookhaven Symp. Biol. 9: 1-22. |