Relationship Between F₁,F₂ Hybrid Yield, Heterosis and Genetic Distance Measur

<正> Genetic distance among 36 cotton cultivars measured by molecular markers of RAPDs, ISSRs, and SSRs was from 0.0701 to 0.4255 with the mean of 0.2844, and from 2.18 to 12.60 with the mean of 7.04 based on the genotype performance in two-year field experiments, which has a significant positive correlation (r = 0.3350). The correlative coefficients for boll number per plant, boll weight, yield per plant, lint percent and lint yield per plant were 0.8035,0.8877,0.7135,0.9640 and 0.8956 between F1 and F2 hybrid performance assessed by three-environment field experiments, respectively. The mean of F1 and F2 hybrid het-erosis of yield per plant and lint yield per plant were 13.62% , 16.31% , 7.90% and 9.02% , and the correlative coefficients between them were 0.3689 and 0.3787, respectively. The correlation between the genetic distance and heterosis was low, and influenced directly by the selected parents.