Metin Tosun

Plant regeneration in wheat mature embryo culture

Success in genetic engineering of cereals depends on the callus formation and efficient plant regeneration system. Callus formation and plant regeneration of wheat mature embryos were assessed by using 12 different methods with 4 genotypes. Genotype significantly affected the formation of callus, embryogenic callus and plant regeneration. Only two methods (methods #2 and 9) produced plant regeneration. The highest plant regeneration for all genotypes with endosperm that supported mature embryos was observed in method #9 which contain MS medium supplemented with 12 mg/l dicamba + 0.5 mg/l IAA. Key words: Callus formation, explant, genotype, plant growth regulators.

Relationship between tissue culture and agronomic traits of winter wheat

Twenty-five winter wheat cultivars (cv.s) were evaluated for their ability to produce embryogenic callus, eventually plantlets, as well as the agronomic performance in the field to determine the relationship between tissue culture and agronomic traits. There were significant genotype effects on callus formation, callus fresh and dry weight, callus moisture content, embryogenic calli formation and the frequency of plant regeneration. Relationship between tissue culture and agronomic traits was examined by correlation and regression analysis. Important relationships between the two traits were found such as the frequency of plantlets regeneration from immature embryos could be estimated from spike number per m2. Such relationships may be due to the fact that plantlets regeneration might be controlled by the genetic system controlling the incidence of spike number per m2 or partial linkage with it. This result suggests that it is possible to screen genotypes with good tissue culture traits directly at the agronomic trait level, a practice rather simple and straightforward.

Determination of Variations of Some Enzymes in Orchardgrass ( Dactylis glomerata L.) Ecotypes

In the present study, wild orchardgrass ( Dactylis glomerata L.) collected from four different locations (Oltu, Olur, Uzundere and Uluba < ) of Erzurum (Turkey) were used to investigate various electrophoretic analyses within and between four ecotypes based on peroxidase (PRX), polyphenol oxidase (PPO) and malate dehydrogenase (MDH) enzymes. Four natural populations of Dactylis glomerata showed genetic variability within and among ecotypes based on similarities and polymorphism of isoenzyme bands. In addition, a dendogram analysis was made according to band patterns indicating that ecotypes could be grouped showing characteristics in relation to each other, notably Oltu-Uluba < and Olur-Uzundere. However, the degree of relationship of Oltu-Uluba < (6 units) was higher than Olur-Uzundere (12 units).

Seed set and some cytological characters in different generations of autotetraploid perennial rye (Secale montanum Guss)

Abstract Artificial autotetraploids of diploid perennial rye (Secale montanum Guss) plants were obtained by colchicine treatment. C1 C2 and C3 generations of autotetraploid perennial rye were compared for seed set and cytological characteristics such as irregularities in metaphase I (univalents) and anaphase I and II (lagging chromosomes and/or chromatids and bridge formation) and micronuclei in tetrads. In the three generations (C1 C2 and C3) the percentage of cells with univalents was 18.51, 14.56 and 9.38% respectively. The percentage of cells with irregular anaphase I with univalents was 23.43, 15.93 and 7.85%, and for anaphase II cells it was 20.93, 16.47 and 7.16. The percentage of tetrads with micronuclei was 18.17, 14.07 and 6.17% and seed set was 27.72, 43.51 and 59.59% respectively. A negative correlation was found between seed set and the cytological characteristics investigated. The correlations among the characters investigated during meiosis division were statistically significant. Selection of vigorous plants of autotetraploid perennial rye increased seed setting by increasing the cytological balance. However, abnormalities in the early stage of meiosis division were reflected in the later stages of meiosis.

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

Heksaploid Triticalede Bazı Sitolojik ve Tarımsal Özellikler Arasındaki İlişkiler / The Relationships Between Some Cytological and Agricultural Characteristics in Hexaploid Triticale

OZET: Bu arastirma, heksaploid triticale cesit/hatlarinda bazi sitolojik ozelliklerin hem birbirleriyle hem de tohum tutma orani ve tane verimi ile iliskilerini belirlemek amaciyla yapilmistir. Meyotik ozellikler arasinda yapilan korelasyon hesaplamalari sonucunda, univalentler ile gecikenler ve cekirdekcikler arasinda pozitif bir iliski belirlenmistir. Yine univalentler, gecikenler ve cekirdekciklerin hem tohum tutma oranini hem de tane verimini olumsuz yonde etkiledikleri ortaya konulmustur. Ayrica, polen canliliginin tohum tutma oranini ve tohum verimini olumlu yonde etkiledigi saptanmistir. Anahtar Kelimeler: Triticale, korelasyon, sitoloji The Relationships Between Some Cytological and Agricultural Characteristics in Hexaploid Triticale ABSTRACT: This study was conducted in order to investigate the possible relationships among cytological characteristics, seed set and grain yield. There were significant correlations among univalents, laggards and micronuclei. Furthermore, univalents, laggards and micronuclei affected negatively both seed set and grain yield. Pollen viability was positively correlated with seed set and grain yield. Key words: Triticale, correlation, cytology

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.