Abstract:Abstract:：The identification and cloning of novel gene controlling rice Panicle Apical Abortion (PAA) is meaningful to understand underlying the molecular mechanism of the trait in order to reduce grain yield losses caused in rice production. We here reported the result of fine mapping to a rice mutant, paa2, derived from tissue culture of Zhonghua 11. Phenotypic analysis found that mutant panicle apical is gradually degraded during the panicle development. Genetic analysis revealed that the paa2 is caused by single dominance gene mutation. Using the BSA method, the PAA2 gene was finally mapped within the interval of 80 kb on chromosome 2, flanked by the newly developed markers of L2-33 and L2-50. The results provided here would beneficial the map-based cloning of PAA2 gene.