Kenaf (Hibiscus cannabinus L.) is one of the most economically important crops for fibre production. Genetic maps have been developed in almost all the agricultural crops. However, genetic information for kenaf, especially, at the molecular level is limited. To better understand the genetic basis of kenaf for the improvement of production and to lay the foundation for molecular breeding efforts, a primary genetic linkage map was constructed using sequence-related amplified polymorphism (SRAP), inter-simple sequence repeat (ISSR) and randomly amplified polymorphic DNA (RAPD). Cultivar ÔAlian kenafÕ and ÔFuhong 992Õ were used as parents to construct an F 2 population consisting of 180 plants. We selected 494 SRAP, 60 ISSR, 120 RAPD and 300 two-primer RAPD mixture primers that amplified 396 polymorphic loci in total. At a logarithm of the odds (LOD) score threshold of 5.0 and at a maximum map distance of 25 cM, these 396 loci were used to construct the genetic linkage map with MAP-MAKER/EXP 3.0, a total of 307 loci were grouped into 26 linkage groups that spanned a total map length of around 4924.8 cM with a mean density of 16.04 cM per locus. These markers were distributed randomly in all linkage groups without any clustering. The construction of the kenaf genetic linkage map will be useful for further genetic studies including mapping both qualitative and quantitative traits, marker-assisted selection program, and comparative genomics analysis.

With the genetic linkage map construction for kenaf and quantitative trait loci mapping, it is possible to perform marker-assisted selection to improve kenaf agronomical important traits at molecular level. In this investigation, using a population with 162 F 2:3 individuals from the cross between Alian kenaf (from Egypt) and Fuhong 992 (from Fujian agriculture and forestry university) with high quality and disease resistance, on the basis of the linkage map we had finished, we finally mapped five qualitative trait genes for leaf petiole color, leaf shape, dimension of corolla, corolla shape, stem color at late stage. Analysis using the Mapmaker/Exp 3.0 software showed that there were close linkage relation between the gene of stem color at late stage and leaf petiole color gene, with a genetic distance of 2.8 cM, which were mapped on the linkage group 5. Also linkage existed between dimension of corolla and corolla shape, with a genetic distance of 14.7 cM, which were mapped on the linkage group 6. The genetic distance between leaf shape and dimension of corolla, corolla shape, were 38.2 cM and 23.5 cM, respectively. They were mapped on the linkage group 6, but their linkage relation still requires further research. The results had certain practical significance and by molecular marker-assisted selection were useful for the research of kenaf genetics and the breeding.

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