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Bu araştırma, İtalyan çimi çeşitlerinin yemkalitesini yükseltmede önemli bir potansiyeli olan azotlu gübrelerin değişikdozlarının etkilerini belirlemek üzere yapılmıştır. Orta Anadolu bölgesi kıraçkoşullarında, 2008 ve 2009 yıllarında yürütülmüştür. Ankara Üniversitesi ZiraatFakültesi Tarla Bitkileri Bölümü deneme tarlasında tesadüf bloklarında bölünmüşparseller deneme desenine göre 3 tekrarlamalı olarak kurulmuştur. Çalışmada azotlugübre olarak amonyum nitrat (% 33 N) gübresinin 0, 4, 8, 12, 16, 20 ve 24kg da-1 dozları ve İtalyan çimi çeşidi olarak da Gemini, Tetraflorumile Lolita kullanılmıştır. Erken ilkbaharda 30 cm sıra arası verilerek ekilenparsellerde gerektiği dönemlerde elle yabancı ot mücadelesi yapılmıştır.Parsellerdeki bitkiler çiçeklenme-başaklanma dönemine geldiğinde gözlemler vehasat yapılmıştır. Çalışmadan elde edilen sonuçlara göre; İtalyan çimi çeşitleriarasında incelenen özelliklerden protein verimi, protein oranı, ham kül oranı,asitte çözünmeyen lif (ADF), nötr deterjanda çözünmeyen lif (NDF) ve nispi yemdeğeri (NYD) bakımından önemli farklılıklar belirlenmiştir. Azotlu gübredozları protein oranı, protein verimi, ADF, NDF ve NYD üzerine etkili olmuştur.Ankara ve benzer koşullarında yapılacakİtalyan çimi yetiştiriciliğinde yüksek verim ve kaliteli yem elde etmek içinLolita çeşidine 8 kg da-1 azot dozu uygulanması tavsiye edilebilir., This research was conducted to determine the effects of different doses of nitrogen fertilizers which have a potential to increase the forage quality of Italian rye grass cultivars. It was carried out at the experimental area of Field Crops Department of Agricultural Faculty of Ankara University between the years of 2008 and 2009. The experiment was designed in split blocks with three replicates in the experimental plots of Field Crops Department of Agricultural Faculty of Ankara University. Nitrogen in ammonium nitrate (33% N) form was applied on main blocks with the amount of 0, 4, 8, 12, 16, 20 and 24 kg da-1 doses. Italian ryegrass cultivars Gemini, Tetraflorum and Lolita were places in sub-plots. Hand seeding was performed in early spring on the rows which was 30 cm apart each other. Weeds were taken out on the plots manually whenever needed. When the plants were at flowering stage, observations were made and plants were harvested for hay. According to the results; statistical differences were found among Italian rye grass cultivars for crude protein rate, protein yield, crude ash rate, acid detergent fiber (ADF), neutral detergent fiber (NDF) and relative feeding value (RFV). Nitrogen fertilizer doses affected crude protein rate, protein yield, crude ash rate, ADF, NDF and RFV. In order to get higher quality forage in the Italian ryegrass cultivation in Ankara and similar conditions, Lolita cultivar and 8 kg da-1 nitrogen fertilizer is recommended according to results of this research.

The pollen size and morphology of 20 Onobrychis Adans. taxa from Turkey were studied using both light and scanning electron microscopy. Of the taxa studied, Onobrychis fallax Freyn & Sint. and Onobrychis elata Boiss. & Balansa showed the smallest size of pollen grains, while the largest were found in Onobrychis aequidentata (Sibth. & Sm.) d'Urv. and Onobrychis viciifolia Scop. The pollens of all taxa studied represent the tricolpate type of pollen and are prolate in shape. The type of exine found in the studied taxa is reticulate (sect. Dendobrychis DC. and sect. Laphobrychis Hand.-Mazz.), suprareticulate (sect. Onobrychis), or microreticulate (sect. Hymenobrychis DC. and sect. Heliobrychis Bunge). A correlation is observed between the pollen size and chromosome number.

The genotoxic potential of the commercial herbicide Illoxan (containing 284 g/L, diclofop-methyl) was determined by using chromosome aberrations in Allium cepa root tip cells. The EC(50) value was determined as 150.00 mg/L using a root growth inhibition test and then the roots were treated with 37.50, 75.00, and 150.00 mg/L concentrations for 12, 24, and 48 h. The results indicated that Illoxan significantly increased the abnormal cell frequency at all concentrations and treatment periods when compared with their controls, and this increase was close-dependent for the 24 and 48 h treatments. On the other hand, Illoxan significantly decreased the mitotic index (MI) in all treatments when compared with their controls. The decrease in the mitotic index was slightly close-dependent for the 24 and 48 h treatments. Illoxan did not affect the percentage of mitotic stages. For the pretreated root tips, Illoxan (except 37.50 mg/L, at 12 and 24 h) significantly increased the frequency of abnormal cells in a dose-dependent manner. This study indicates that Illoxan decreased the mitotic index and produced clastogenic and aneugenic types of abnormalities in Allium cepa root tip cells. The data obtained in this study showed that plant bioassays call be used as ail important test battery to detect possible genotoxicity of chemicals.