QTL Mapping for Days to Flowering under Drought Condition in Rice (Oryza sativa L.) Genome

QTL for days to flowering in rice under drought condition were mapped using a DH population derived from a cross between a deep-rooted upland adapted japonica genotype 'CT9993-5-10-1-M' and a lowland adapted shallow-rooted moderately drought tolerant indica genotype 'IR62266-42-6-2'. QTL mapping was performed following three different mapping models viz. simple (SIM), composite (OM) and multiple mapping model (MIM) using WinQTL Cartographer version 2.5.006. SIM located 12 QTL for days to flowering spread over nine chromosomes whereas CIM and MINI each located 5 QTL with a threshold LOD score of 2.5. A comparison of the QTL detected by three different models identified five QTL, that were common across at least two models for days to flowering. In MIM analysis, the detected QTL (qHD-1-b) between flanking markers (RG109-ME1014) located on chromosome I recorded positive effect (1.4090) but the remaining four QTL had negative effect. The QTL (qHD-3-a) detected between flanking markers (RG104-RG409) by both MIM and SIM in the present study was also reported earlier as linked with the marker RG104. The. five common QTL detected by at least two models could be considered as stable QTL for days to flowering under drought and might be of practical use in marker assisted selection.