Ecological Regionalization of Cotton Fiber Quality Based on GGE Biplot in Yangtze River Valley Cloning and Expression Analysis of GhANS in Gossypium hirsutum Molecular Identification and Expression Analysis of  GhCYP51G1 Gene,a Homologue of Obtusifoliol-14α-demethylase Gene, from Upland Cotton(Gossypium hirsutum L.) Cloning and Expression Analysis of Three Aquaporin Genes in Upland Cotton (Gossypium hirsutum L.) Physiological Mechanism of Sucrose Metabolism in Cotton Fiber and Fiber Strength Regulated by Nitrogen