Towards the Development of Saturated Linkage Map and Functional Markers for Root-Knot Nematode (RKN) Resistance Loci in Upland Cotton

The resistant line Auburn 623RNR and a number of elite breeding lines derived from it remain the most important source of resistance because they exhibit the highest level of resistance to RKN know to date in cotton. Identification and characterization of the resistant genes in this resistant source is of great interest to cotton nematologists and breeders. Primary objectives of this study are to develop a saturated linkage map of Chr.14 and to identify candidate genes for functional marker development that will greatly facilitate the improvement of RKN resistance in Upland cotton via marker-assisted breeding. Prior genetic mapping analysis has identified two QTLs, qMi-C11 and qMi-C14, conferring resistance to RKN in the Auburn 623RNR source. The QTL qMi-C11 is identified on an 810 Kb region flanked by markers CIR316 and CIR069 on Chr.11 while the QTL qMi-C14 is identified on a 2.3 Mb region flanked by markers BNL3644 and CGR5668 on Chr.14. The narrow QTL region on Chr.11 have been fairly saturated with additional AFLP markers, the region on Chr.14 remains sparsely saturated.