OZET Diploid Ingiliz ciminden tetraploid Ingjfiz ciminin elde edilmesi, bunlarin sitolojik ve morfolojik karakterlerinin mukayesesi gayesi ile yapilan bu arastirmada %O,2'lik Kolkisinle 24°C'de muamele edilen 1500 fideden % 1.6 oraninda tetraploid bitki elde edilmistir. Diploid L. perenne 2n=14, tetraploidlerde 2n=28 oldugu tesbit edilmistir. Diploidlerin her genomunda 3 satelitli kromozom bulunmustur. Kromozomlarm 3 tanesi median, 4 tanesi ise submedian se~lromerlidir. Tetraploid Ingiliz ciminin kromozom yapilan ve buyuklukleri diploidIerden farkli olmayip sadece tetraploidlerde kromozom sayilan diploidlerin iki mislidir. Diploidlerde diakinez devresinde kromozomlar ni (yedi bivalan) ,meydana getirmesine karsilik, tetraploidlerde cok karisik kromozom baglantilari bulunmustur. Kromozomlarm multivalanlar meydana getirmesi meiozun ,duzensiz seyretmesine sebep olmaktadir, Meiozun gayrimuntazamligi neticesinde fertilite dusmus ve tohum tutma oram azalmistir. Morfolojik karakterler arasmdaki farklarm o'nemli olup olmadiklarmi tesbit icin t kontrolleri yapilmis, genelolarak tetraploidlerin morfolojik karakterler yo'nunden ustun olduklari tesbit edilmistir. POSSIBILITIES OF OBTAINING TETRAPLOID PERENNIAL RYE GRASS (Lolium perenne L.) FROM DIPLOID PERENNIAL RYEGRASS AND COMPARISON OF MITOTIC AND MEIOTIC CHROMOSOMES AND SOME MORPHOLOGICAL CHARACTERISTICS OF THESE PLANTS The results of these experiments conducted to obtaine tetrapIoid perennial ryegrass (lLJlium pereiine L.), and to compare mitotic, meiotic chromosomes and morphologicaI characters of these two plant types, can be summarized as folIows: :' i. To ,obtaine tetrapIoids, 1500 diploid perennia) ryegrass seeds were genninated at 24°C, in gerinination chamber. Before the emergence of first leaf from coleoptile, seedlings were put into 0.2 %aquecus colchicine solution, at 25Co, for three hours, After then, the seedlings which had been washed 6 times, were put in the germination chamber for }-4 days -and then transfered tonat boxes. At the end of two months, the survivors wer traasplanted to pots. Consequent1y, 1.6 % of the original seeds employed, were obtained as tetrapIoid 'perennial rye giass. 2. it was determined tha~ <tiploid perennia) ryegrass had a chfomosome number of 211 =14. In each genome. three chfomosomes had satellites. Three chromosomes had median and four chfomosomes had submedian centromeres. 3. No differences couId be found between the caryotypes of diploids and artificial tetiaploids. But, the number of chromosomes in artificial tetrapIoids were doubled (2n = 28). 4. In <tiploids, at the stage~, diakinesis and metaphase I, chromosomes were 128 found to be in the form of 7 II. Thus , the the meiotic division was normal; conceqauntely normal poiien grains were produced, and fertility was high. 5 In diakninesis and metaphase i stages of the tetraploids, paiiing of the chromosomes varied very much The multi:valent formations caused abnorlmalities in meiotIc divisions The pairing forms of the 165 poIlen mothei cell~ studied, were as fol1ows: 15 %2 II + 6 LV, 48 % 4 II + 5 iv. 16 % 6 II + 4 IV, 16 % 8Il + 3 IV In addition t9 these uni and multi valent chiomosames were found in the ratio of 5 % Because of the abnorma lities in the meiotic division, feitility and seed set were low 6 The differences between the morphological characters were tested, using t test As a result, length and width of polIen grains, of the stomata, of glumes, of paleas, the number of nowers p~r spikelet, thickness and width ot leaves of the tetraploid were greater than that of the diploids and the differences were significant at 1 'vo leveL. The length of the leaves oftetrap loids significant1y greater than that of <tiploids, at 5 % leveL. The number of spikelets and tillers were significantly higher in <Jiploids, at 5 % level No significant <tifferences were found in the length of rachis and compactness of the spike between diploids and tetrapioids were faund.