| The meiotic analysis and morphological characters of
the hybrid Triticum durum Desf var. hordeiforme Korn. x Aegilops
speltoides Tausch Murat OZGEN University of Ankara, Faculty of Agriculture Department of Field Crops, Ankara, Turkey It has long been known that Aegilops and other close relatives of wheat are resistant to various wheat diseases of which most important are rusts (Puccinia spp.). Therefore, in spite of various limitations such as difficulty in crossing, and low fertility, they have been maintaining the importance, as gene sources in resistance breeding programs for a long time (HIRATSUKA 1955, SEARS 1956, DYCK & KERBER 1970, DVORAK 1977, DVORAK & KNOTT 1980). In this research, some morphological characters, meiotic configurations and level of resistance to stripe rust (Puccinia striiformis West.) of F1 hybrid of T. durum var. hordeiforme x Ae. speltoides were studied. Materials and Methods Widely grown durum wheat variety Cakmak 79 (T. durum var. hordeiforme, 2n = 28), which was susceptible to stripe rust, and Ae. speltoides (2n = 14), which was resistant to stripe rust, were used as parents. Parents and F1 hybrid were tested at both seedling and adult-plant stage by a mixture of spores which was consisted of prevalent races of stripe rust. Growing of parents, emasculation and pollination were made under field conditions with the techniques given by OZGEN (1983a). The obtained seeds from the crosses were germinated under laboratory conditions. Chromosome number was observed in root-tip mitosis using the Feulgen squash method. During the winter all seedlings were grown in the greenhouse and then transplanted to the field in early spring. Immature spikes of the F1 hybrid were fixed in 1:3 asetic acid-alchol for 24 hours. Fixed spikes were stored in 70 per cent alchol at 0-4C. Pollen mother cells (PMC's) were stained with acetocarmine. Chromosome pairing was analyzed in the PMC's at metaphase I. Slides were sistematically scanned and pairing configurations recorded. Rachis toughness, spike density, feature of lower internodes and growth habit were studied as morphological characters. Results and Discussion In crossing program, 404 florets from 17 spikes of T. durum var. hordeiforme were pollinated by Ae. speltoides and 62 seeds were obtained. Chromosome numbers were determined by examining root-tip mitosis and eventually hybrids were found to be triploid (2n=21) (Fig. 1). As it is known, due to genomal incompatibility between endosperm and embryo, and mitosis abnormalities in embryo reduce the germination ability of the seeds which are obtained from interspesific crosses (LILIENFELD 1951, KIHARA & YAMASHITA 1956, STEBBINS 1958). Therefore, only 21 of the 62 hybrid seeds were germinated under laboratory conditions. The seedlings were transplanted to the field and 12 F1 plants with spike were obtained. |
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