ABSTRACT

Clarification of the genetic basis for root-knot nematode (RKN) resistance in the Auburn source and development of closely linked markers to the resistance could finally put the RKN resistance gene(s) to work in cotton breeding. This study was conducted to verify the genetic mechanism of the Auburn source and to verify and identify molecular markers for the RKN resistance. Two F2 populations using Auburn 634 and its derived resistant line M-240 confirmed that the resistance is either controlled by one dominant gene or one dominant gene and one recessive gene. By comparing several pairs of near isogenic lines (NILs) with or without the Auburn source resistance, none of the previously reported RAPD and SSR markers exhibited consistent polymorphism, indicating that they were not closely linked to the RKN resistance. However, several SSR and two RGA markers were identified to be consistently polymorphic between the NILs. These markers will be employed in our mapping populations to evaluate their linkage with the RKN resistant gene(s).