Abstract: Objective and MethodThe correlation betewwn growth periods(the days of budding, flowering, opening boll) and agricultural traits(plant height and first fruiting branch node) were analyzed in a F_2 population, which was derived from a cross between Ghirsutum L."Jin13" and Gbarbadense L. "Hai7124". And QTLs detection of these traits were employed in this population. ResultThe conclusion showed that the day of opening boll was positively correlated with the day of budding, flowering, boll setting, but negatively correlated with plant height, and no significant correlation with first fruiting branch node. A total of 18 QTLs were detected by composite interval mapping, including 4 QTLs for opening boll on chromosome 2, 22, 25 and D3. The variances explained by each QTL from 69.6; to 89.9;. The QTLs for budding to opening boll and flwering to opening boll were detected in the same area of chromosome 2, 25 and D3. 2 QTLs for budding were separately detected on chromosome 9 and 17. 2 QTLs for flowering were separately detected on chromosome 15 and 26, and 2 QTLs for bud setting were detected in same area of these chromosomes. The QTL for plant height and first fruiting branch node were detected in same area of chromosome A3.ConclusionThese QTLs have provided evidence for early maturing cotton breeding .