Genetic control of cellulose, lignin and glucose contents in European black poplar (Populus nigra L.) populations from Turkey


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Biyolojik Bilimler Bölümü, Türkiye

Tezin Onay Tarihi: 2014

Öğrenci: BİRCAN TAŞKIRAN

Danışman: ZEKİ KAYA

Özet:

Populus nigra L. is considered as one of the most economically significant forest tree species with respect to production of wood, biomass, timber, pulp, paper and other wood-based products, besides its ecological and evolutionary importance. Because of the increased wood needs of the world and demands of renewable energy sources, fast-growing poplar has gained importance. While wood quality, pulp mechanical strength, and biomass are directly associated with high cellulose content, lignin emerges as an undesirable polymer for both pulp and biofuel manufacturing industries. To estimate the contents of the main cell wall polymers, cellulose, lignin, and total D-glucose content of wood cell, and also their proportion to each other, we established a large collection of biological samples from one year old branches of poplar trees (285 clones x 3 replicates x 2 ramets) which were grown for three years in an outdoor nursery (Behiçbey Nursery) in Ankara. These clones were originally collected from all over Turkey. Additionally, five commercially registered clones and six foreign clones were included in the study for comparison. The mean values for cellulose, lignin and glucose content were 21.8 ± 16.29 µg/ml, 23 ± 4.64 µg/ml, and 35 ± 9.71 µg/ml, respectively. However, particular clones were detected with extraordinary high values for these traits. The components of the total variance due to among clones within regions were 15.11 %, 3.47 %, and 12.94 % for cellulose, lignin and glucose, respectively. Positive correlations were observed between cellulose and height (r = 0.22; p < 0.01), cellulose and diameter (r = 0.23; p < 0.01) and also between lignin and glucose (r = 0.31, p < 0.01). On the other hand, negative correlation was detected between lignin and diameter (r = -0.121; p < 0.05) as expected. In the study, all clones were also evaluated with respect to high quality and yield to realize valuable clones with high cellulose to low lignin content. The superior clones were 62172, N91075, 62160, N03377, and 62191, whereas the inferior clones were 641410, N91085, 8511, N03372, and N92169. Also the study by choosing the superior and eliminating the inferior clones pave the way for future investments and applicable new poplar breeding programs.