QTL Mapping for yield components and quality parameters in sugarcane

Sugarcane is an important crop with a complex genome, in which Molecular Biology technology can help the understanding of important traits, and can make sugarcane breeding programs even more efficient. The objective was to perform QTL mapping in traits related to yield, in a full-sib cross obtained from cultivars derived from IAC Breeding Program. For this, a genetic map was constructed using 25 Amplified Fragments Length Polymorphism (AFLP), 35 Genomics Microsatellites (gSSR) and 105 Expressed Sequence Tags (EST-SSR). In the total were found 113 Linkage Groups, with 409 markers and 4370 cM. QTL mapping was done for Tones of Sugar per Hectare (TSH), Cane Yield (TCH) and Fiber Content, in two years (cane plant and first ratoon). Estimatives of phenotypic values were obtained with mixed models approach considering multiple harvest. Interval Mapping approach was applied with threshold of LOD Score 2. For all traits, 14 QTL was detected in ten LG, three mapped for TSH are responsible for 5.95% of the total phenotypic variation (R²), six for TCH (31.75%) and five for Fiber (20.51%). The biggest phenotypic variation was an increase of the 17.64% for TCH in the individuals that have the flanking markers actctt32 and cgcacc03 in the LG7. The LG14, LG35, LG44 and LG65 contain two different QTL, TCH and Fiber in the LG35 and TCH and TSH for the remainder. These observations reinforce the importance of knowing these genome regions.