Research on Exogenous Hormones Sensitivity on Plant Height of a Semi-Dwarf Mutant in Upland Cotton

【Objective】 The aim of this study is to illuminate the sensibility of the exogenous hormones to plant height of a dwarf mutant in upland cotton so as to determine which kind of hormone sensitivity the mutant belongs to, which will facilitate dissecting the relationship between the genetic basis of plant height and hormonal regulation in cotton.【Method】The cultivated upland cotton variety Xinluzao 17 and its dwarf mutant were used as experimental materials. The plant height variations of the two cottons were observed under different hormone types and different concentrations.【Result】The mutant was approximately three-quarters of the plant height of Xinluzao17, which indicated that the mutant was a typical semi-dwarf mutant in upland cotton. After the cottons were treated with GA₃, the plant height of Xinluzao17 was higher than that of the mutant. Treated with 50 mg/L GA₃, plant height of the mutant could be resumed to the plant height of Xinluzao17, a normal plant height cultivar. It suggested that the plant height of the mutant was sensitive to GA₃. The order of the effects of phytohormone on cotton plant height was GA₃> BR> IAA. Pearson correlation analysis showed that the plant height had a significant positive correlation with GA₃. It further suggested that the mutant was a GA₃ sensitive dwarf.【Conclusion】The mutant is a typical semi-dwarf in upland cotton. The plant height of the mutant is sensitive to exogenous GA₃.