title: RNA-Seq of IBM-RIL backcross hybrids_part 1
design: 112 IBM-RIL inbred lines were selected and backcrossed to the maternal in bred lines B73 and Mo17. The backcross hybrids, their parental inbred lines and the reciprocal hybrids of B73 and Mo17 were surface sterilized and germinated in moist germination paper for 3 days. 3DAGs eight seedlings representing comparable developmental stage were transplanted to hydroponic systems. At 7DAG the lower part of primary roots, i.e. without lateral root primordia, of the seedlings were harvested in three biological replicates, each sample consists of 8 pooled primary roots. The total RNA of pooled root samples was isolated with the RNeasy Plant Mini Kit (Qiagen, Venlo, The Netherlands). cDNA synthesis and libraries for Illumina sequencing were constructed according to the protocol of the manufacturer (Illumina, San Diego CA, USA).