Mapping of bioenergy-related traits QTLs using next generation sequencing method in sweet sorghum

In this thesis, genomic library was constructed using with ddRAD-seq (double-digest Restriction Site Associated DNA) method in F2 population consisting of 181 individuals derived from a cross between sweet sorghum, Erdurmus and grain sorghum Ogretmenoglu which were contrasting cultivars for plant height, sugar content and Brix data were obtained using the libraries by next generation sequencing method. Phenotypic observations on plant height, stalk juice and Brix characteristics were performed in the F3 population grown in Konya and Antalya locations. Three major QTLs on the chromosomes 1, 7 and 9 for plant height, 1 major QTL on the chromosome 6 for stalk juice and 2 minor QTLs on the chromosomes 3 and 7 for Brix were determined by QTL mapping. The qPH1.1, qPH7.1 and qPH9.1 QTLs for plant height explained the phenotypic variation of 10,8, 34,8 and 13,5%, respectively. The explanation rate of the qPJ6.1 QTL was 26% for the phenotypic variation of stalk juice while the qBX3.1 and the qBX7.1 for the Brix were 8,6 and 9,7%, respectively. The SNP at the SCM_59803007 location, which was close the qPH7.1 QTL region was identified at about 30 kb from the Dw3 gene, and the phenotypic variation was explained for 34.8%. As a result of the SNP determined in the analyses performed in this region, it was observed that the 120th amino acid at the 4th exon was changed to Aspartate (D) to Glutamate (E). From the SNPs in the defined QTL regions, 2 CAPS (Cleaved Amplified Polymorphic Sequences) markers for plant height, 2 CAPS for stalk juice and 3 CAPS for the Brix characters were developed for user friendly MAS selections. The conversion efficiency of genomic sequence data to CAPS marker was determined as 100% for each marker according to data especially having from the 8 lines and 1 cultivar whose genomic sequences were known. Next generation sequence data of 8 different lines and Uzun cultivar, which no contain the QTLs of the Erdurmuş cultivar in terms of plant height, stalk juice and the Brix characters, but are still superior in terms of these characters, were scrutinized. To provide the pyramiding of different QTLs in Erdurmuş cultivar, lines and cultivars with different SNP QTL regions were crossed with Erdurmuş and the progenies were evaluated for the characters studied. Especially in the observations in crossings of 507 and Erdurmuş and (424 x Erdurmus) X (507 x Erdurmus), it was observed that the values obtained for plant height and the Brix characters were considerably higher than their parents, and thus genome-based pyramiding were successful.