Differential gene expression and associated QTL mapping for cotton yield based on a cDNA-AFLP transcriptome map in an immortalized F2

cDNA-AFLP techniques have found new applications in recent years. Currently, the methodology is used to establish differential gene expression and construct linkage maps. In the present study, a transcriptome map based on cDNA-AFLP techniques was constructed using an immortalized F-2 (IF2) population of 171 lines. The lines were derived from intercrosses between 180 recombinant inbred lines (RILs) of the cotton hybrid Xiangzamian 2 (Gossypium. hirsutum L.). A total of 302 transcriptome-derived fragments (TDFs) were mapped onto 26 linkage groups that covered 2,477.06 cM in length with an average distance of 8.23 cM between two markers. Seventy-one QTL for yield and yield component traits were detected by CIM procedures based on four environments, with 13 QTL identified in at least two environments. Some TDFs co-located with yield QTL were subsequently sequenced and analyzed by online homology searches. Potential candidate genes for yield and yield component traits were found to encode proteins involved in DNA replication, transcription, translation, and biosynthesis regulation. Furthermore, genes regulating metabolic processes signal transduction, transport, and structural components of organelles were identified. Correlation analysis between expression patterns of TDFs and trait performance detected six TDFs positively correlated to both yield and yield heterosis: six TDFs positively correlated to yield, and seven TDFs to yield heterosis. These TDFs have potential for cloning the functional genes responsible for each corresponding trait and have future value in marker-assisted selection.