据报道,美国对棉花良种繁育比较重视。为了保持生产上推广品种的良好生产力和优良经济性状,用作播种的种子每隔几年就更换一次,用原种繁殖的种子来替代。在美国生产上推广的棉花品种的原种种子,每年由各该品种的育种者负责供给。只要品种还保留在生产上,品种的选育者就必须每年交给良种繁育机构一定数量的具有该 It is reported that the United States places more emphasis on the breeding of cotton varieties. In order to maintain the good productivity and good economic traits of the varieties that are being promoted in production, the seeds used for sowing are replaced every few years and replaced with the seeds of the original breed. The original seed of the cotton variety promoted in the United States is supplied annually by the breeders of the breed. As long as the breed remains in production, the breed’s breed must be given annually to the breed’s breed for a certain number of breeds