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长期以来棉花育种的主要手段一直采用品种间杂交和系统选择方法，由于所有栽培品种都起源于少数共同原始类型，亲缘关系过近，遗传基础贫乏，致使育成品种的增产幅度小、退化快，经济性状也难以提高，特别是纤维强力不够、抗病虫及抗逆性差。为此，国内外育种界普遍认为从众多?
Long-term cotton breeding has been the main means of cross-species hybridization and the system selection method, because all cultivars originated in a small number of common primitive type, genetic relationship is too close, lack of genetic basis, resulting in increased yield of bred varieties is small, rapid degeneration, economy Traits are also difficult to improve, especially fiber strength is not enough, resistance to pest and poor resistance. To this end, the breeding industry generally believe that from many?