一、引言棉花原产于热带与亚热带,从本性上来说是短日性类植物。但经历史上劳动人民的长期驯化栽培,在高纬度地区(目前主要产棉区)的栽培品种和低纬地区栽培的一年生早熟品种,已大大地改变了原始棉种的多年生和短日发育特性,在完成开花准备(光照阶段)所要求的短日特性上,已变得反应不敏感。这种事实只是证明了品种的各发育 I. INTRODUCTION Cotton is native to tropical and subtropical regions and is, in its nature, a short-term plant. However, through long-term domestication and cultivation of working people in history, cultivars cultivated in high-latitude regions (currently the main cotton-growing areas) and annual early-maturing cultivars cultivated in low latitudes have greatly changed the perennial and short-day developmental characteristics of primitive cotton species, It has become insensitive to the short-day characteristics required to complete the flowering preparation (light phase). This fact only demonstrates the variety of development