Mapping QTLs related to rice roots and shoots traits in recombinant lines derived from Anbarboo × Sepidroud under drought stress conditions

To identify the genomic regions associated with drought stress tolerance using QTL analysis, 96 F8 lines derived from a cross between two varieties, Sepidroud and Anbarboo, were planted at a research field in Azadshahr region, Golestan Province, Iran, in 2011. To impose drought stress, irrigation interval was considered as 20 days from maximum tillering phase to maturity stage. The linkage map was constructed using 124 microsatellite markers and 264 AFLP markers at the laboratory of Genetics and Plant Breeding, Gonbad-e-Kavous University, Golestan, Iran, which covered 1950.4 cM of the rice genome with average distance of 5.20 cM between adjacent markers. In this study, regions of chromosome 2 at the interval of E070-M140-1-E070-M150-13, chromosome 4 at the interval of E060-M160-3-RM1359 and chromosome 9 at the interval of E120-M140-9-E090-M140-14 were identified that controlled several traits under drought stress conditions. Co-locating of the QTLs involved in control of traits can indicates same genetic controlling. QTL mapping of traits indicated QTLs qRND-2a, qRND-4a, qRVD-2, qRVD-4a, qFRWD-2, qFRWD-4, qDWRD-2a, qSWD-2a, qSWD-4, qPWD-2, qPWD-4, qPND-2a, qPND-4 and qPSPD-9 had a large effect and more than 20% of the explanation of phenotypic variation, respectively. Considering that these genomic regions explained a significant part of phenotypic variation therefore those have potential for application in the breeding programs of Marker-assisted selection for drought tolerance after validation in other environments and populations.