This is a sentence picked from the paper mentioned afterwards. "A total of 67 and 35 QTL were detected under water-limited and well-watered conditions, respectively. The favorable alleles to improve the traits exhibited partial or over-dominance effects".
How to identify the role of alleles and the kind of gene action based on QTL anaysis for any trait. Ref: (PDF) Progress and perspective on drought and salt stress tolerance in cotton. Available from: https://www.researchgate.net/publication/329935232_Progress_and_perspective_on_drought_and_salt_stress_tolerance_in_cotton [accessed Mar 31 2020].