Fuente: WIPO "tobacco agriculture" The invention relates to a flower root knot nematode disease resistant QTL qRprkn-LG21, and an SSR marker, a kit and a method thereof, and belongs to the technical field of molecular biology. The peanut root knot nematode disease resistance QTL qRprkn-LG21 is located in a physical segment between the 109325613 site and the 110191973 site of a tobacco genome LG21 chromosome. The invention further provides an SSR (Simple Sequence Repeat) marker for detecting the QTL qRprkn-LG21 resistant to the root knot nematode disease of the flower, wherein the SSR marker comprises a marker Ma21040 and a marker Ma21163. Experiments prove that the SSR marker is adopted for screening filial generations of disease-resistant parents, and a single plant which carries the peanut root knot nematode disease resistance QTL qRprkn-LG21 and has high peanut root knot nematode disease resistance can be detected very accurately.>>