Abstract: The performance of aphid resistance，quantified by aphid damage index，was evaluated for the 113 randomly selected F1 lines derived from‘Nannong Xuefeng’בMonalisa’at seedling stages under greenhouse condition，and the genetic variation and QTL responsible for aphid resistance were examined in the present study. The result showed that aphid damage index ranged between 0.20–0.92 and distributed normally with a coefficient of variation of 36.73%，indicative of the quantitative nature；in addition，transgressive segregation was observed in both directions，which basically accords with the trend of bimodality. Major gene plus polygene inheritance model analysis figured out the inheritance of aphid resistance fitted B-2 model that was governed by two major genes showing additive-dominant effects，and the heritability of the major genes was calculated at 0.91. QTL analysis based on the composite interval mapping method detected four aphid-resistance-associated QTLs，namely ArX3，ArX4，ArX30 and ArM9，harboring on the linkage group X3，X4 and X30 of‘Nannong Xuefeng’map and M9 of‘Monolisa’map， with a LOD value of 2.40–3.52. The additive effect of the four QTLs varied in a range of–0.16–0.18，and the individually explained phenotypic variation ranged from 5.90% to 9.38%，therefore the identified QTL should be minor genes.

Key words: chrysanthemum, aphid resistance, genetic variation, major gene plus polygene, quantitative trait loci（QTL）