High-density genetic map construction and QTL analysis of the first flower node in kenaf using RAD-seq

In kenaf (Hibiscus cannabinus L.) which is an important natural fiber crop, the first flower node is closely linked to fiber yield. However, the genetic mechanisms controlling the first flower node remain poorly understood.

In this study, we constructed a high-density genetic linkage map using Restriction-site associated DNA sequencing (RAD-seq) technology based on 148 individual hybrid kenaf progeny. The map contained 3418 bin markers unevenly on 18 linkage groups and spanned a total of 864.607 cM with an average distance of 0.253 cM. Based on the genetic map, two major QTLs, FFN6.1 and FFN6.2, were detected on LG6 and were strongly associated with the first flower node. Based on annotation information in the GO, KEGG and NR public databases, 373 candidate genes were predicted in the FFN6.1 and FFN6.2 regions. Finally, using RT-qPCR, three genes related to the first flower node were identified.

The study provides a good foundation for understanding the molecular mechanisms of the first flower node trait in kenaf.