Sevim Sağsöz

Meiosis in hexaploid triticale

Meiosis was studied in five high-yielding and five low-yielding triticale genotypes. The percentage of metaphase I cells without univalents was 75.0%. The average number of univalents per cell was 0.56. Percentage of regular anaphase I cells was 80.1% and the average number of laggards per anaphase I cell was 0.48. On the other hand, 77.1% of anaphase II cells had regular chromosome distributions and the average number of laggards per anaphase II cell was 0.64. The percentage of tetrads without micronuclei was 73.5%, and the mean number of micronuclei per tetrad was calculated as 0.77. The percentage of pollen viability was 74.5%. It was determined that high-yielding genotypes were usually better than low-yielding genotypes in all traits.

Test weight, kernel shrivelling, and aneuploidy frequency in triticale

Abstract Kernel shrivelling is one of the main problems in kernel appearance and test weight that cause yield loss. Aneuploidy frequency and its relationship with kernel shrivelling were determined in four triticale genotypes. Firstly, genotypes were divided into two main groups based on their test weights. Secondly, these two groups were subdivided into two subclasses based on kernel appearance. While euploids rate was 100% in plump kernels of high test weight genotypes, this rate was 92 and 94% respectively in a group of shrivelled kernels. Ploidy levels of 2n = 40 and 2n = 41 were observed in aneuploids. A ploidy of 2n = 40 chromosomes was not observed in the plump kernel group of high test weight genotypes, but in the shrivelled kernel group made up 1%. While there were no aneuploids in the plump kernel group of high test weight genotypes, the aneuploidy rate was 7% in the shrivelled kernel group of same genotypes. On the other hand, the aneuploidy rate was 8 and 13% in the plump and shrivelled kernel groups of low test weight genotypes, respectively.

Buğdayda Olgun Embriyo Kültürünü Etkileyen Faktörler / Factors Affecting Wheat Mature Embryo Culture

OZET: Bu calisma bugdayda olgun embriyo kulturunu etkileyen faktorleri belirlemek amaciyla yapilmistir. Kallus, embriyogenik kallus, somatik embriyo olusumu ve rejenerasyon kapasitesine genotipin, jel yapici maddenin, oksin tipleri ve dozlarinin etkisi cok onemli olmustur. Bugday olgun embriyo kulturunde oksin tipi olarak dikambanin, 2,4-D ve pikloramdan, yine jel yapici madde olarak phytagelin, agardan daha etkiligi oldugu saptanmistir. En yuksek kallus, embriyogenik kallus ve somatik olusumu ve de bitki rejenerasyon kapasitesi phytagel ortamindaki dikambanin 4 mg/l dozunda elde edilmistir. Rejenerasyon ortaminin rejenerasyon kapasitesine etkisi cok onemli olmustur. En yuksek rejenerasyon kapasitesi R1 (0.1 mg/l 2,4-D + 0.5 mg/l BAP) iceren ortamda meydana gelmistir. Anahtar kelimler: Genotip, oksin, jel yapici madde, rejenerasyon ortami, Triticum aestivum ABSTRACT: This study was carried out to determine the factors affecting wheat mature embryo culture. Effects of genotype, solidifying agents, auxin type and doses were found highly significant on formation of callus, embryogenic callus and regeneration capacity. Dicamba as an auxin type was better than 2,4-D and picloram and phytagel as a solidifying agent was better than agar in wheat mature embryo culture. The highest formation of callus, embryogenic callus and regeneration capacity were observed in medium containing 4 mg/l dicamba solidified with phytagel. Regeneration medium influenced significantly regeneration capacity. The highest regeneration capacity (R1) was observed in medium containing 1 mg/l 2,4-D + 0.5 mg/l BAP. Key words: Genotype, auxin, solidifying agent, regeneration medium, Triticum aestivum

AUTOPOLİPLOİD YEM BİTKİLERİNDE TOHUM ÜRETİMİ ÜZERİNE ANEUPLOİDİNİN ETKİSİ

OZET: Cesitlerin devamliliginda en onemli husus uretim esnasinda hicbir genetik degisikligin ortaya cikmamasidir. Bununla birlikte tohumla uretilen turlerde her uretim cemberinde gamet, zigot, tohum ve bitki seviyesinde dogal bir seleksiyon vardir. Yapay autopoliploidlerde ozellikle ilk generasyonlarda aneuploidler yuksek oranda bulunmaktadir. Aneuploidler tohum verimini dusurdugu gibi uretim esnasinda ortaya cikan seleksiyon islemlerini de etkilemektedir. Yapay olarak elde edilmis turlerin aneuploidiye karsi toleranslari farkli olup, bazi turlerde euploid bitkilerde dengesiz kromozom ayrilisi egilimi daha fazladir. Euploidlerde gorulen bu kararsizliga cevresel faktorler (hava, polen uretim miktari, bitki yogunlugu gibi stres kosullari) onemli derecede etki yapmaktadir. Dengesiz kromozom ayrilisi gosteren gamet ve zigotlarin canli kalabilme sansinin yuksek olmasi nedeniyle, bu turlerde aneuploidlerin tamamen populasyon icerisinden seleksiyonla uzaklastirilmasi cok zordur.

BAZI TRİTİCALE GENOTİPLERİNDE KENDİNE VE YABANCI TOZLAŞMA ORANLARININ BELİRLENMESİ

OZET: Erzurum ekolojik kosullarinda 1995-1996 urun yilinda triticalenin 2 cesit ve 3 hatti ile yurutulen bu denemede yabanci tozlasan, kendine tozlasan ve islem uygulanmamis basaklarda basaktaki tohum sayisi, tohum tutma orani ve tohumlarin 1000-tane agirligi uzerinde durulmustur. Deneme sonucunda, incelenen her uc ozelligin uygulamalara gore onemli derecede farklilik gosterdigi, buna karsin genotipler arasindaki varyasyonun yalnizca 1000-tane agirliginda onemli oldugu belirlenmistir. Kastre edilmis, kendilenmis ve islem uygulanmamis basaklarda tohum sayisinin sirasi ile 2.14-3.59, 12.22-13.17, 16.15-17.90 adet, tohum tutma oraninin %10.70-16.30, %61.12-66.90, %80.90-89.52, 1000-tane agirliginin ise 16.03-25.24, 42.69-47.76, 41.30-48.12 g arasinda degistigi tespit edilmistir. Triticalede yabanci tozlasma oraninin dusuk oldugu (ort. %13.59) ve bu ozelligin genotiplere gore cok az degisiklik gosterdigi saptanmistir. DETERMINATION OF PERCENTAGE OF SELF AND CROSS POLLINATION IN SOME TRITICALE GENOTYPES ABSTRACT: This study was conducted under Erzurum conditions in 1995-1996 season with 2 triticale cultivars and 3 triticale lines. Grain number per spike, percentage of seed set and 1000-grain weight in cross pollinated spike, self pollinated spike and intact spike were determined. In this researche, three characters studied significantly varied with the treatments, whereas variation only 1000-seed weight among the genotypes was significant, for the emasculated, self polinated and intact spikes, seed number were 2.14-3.59, 12.22-13.17 and 16.15-17.19, percentage of seed set 10.70-16.30%, 61.12-66.90% and 80.90-89.52%, and1000-grain weight 16.03-25.24, 42.69-47.76 and 41.30-48.12 g respectively. These result indicated that the cross pollination of triticale was lower (avg. 13.59%) and this characters showed slight variation among genotypes.

SOMAKLONAL VARYASYON VE BİTKİ ISLAHI

OZET : Somaklonal varyasyon doku kulturunde ortaya cikan karyotipik (kromozomlardâki sayisal degisiklikler), kromozomal (kromozomlardaki yapisal degisiklikler) ve molekuler degisikliklerin sonucunda meydana gelen kalitimsal degisikliklerdir. Ancak, istenilen ozelliklere sahip varyantlarin orani dusuktur, in vitro kulturde morfolojik ve tarimsal ozellikler yonunden onemli varyasyonlar gorulmustur. Doku kulturundeki mutantlardan yararlanilarak hastaliklara, tuzluluga ve soguga dayanikli hatlar gelistirilmistir