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修饰回交育种法是将杂种品系间杂交和回交方法结合起来,用于棉花多个优良性状聚合的育种改良方法。随着分子标记技术日益完善地用于育种的选择中,提出了分子标记辅助选择的修饰回交聚合育种方法。它以生产上推广或即将推广的品种为轮回亲本,将修饰回交育种法和分子标记辅助选择育种相结合,同时对轮回亲本的遗传背景和具有育种目标性状的基因或QTL进行选择,从而可显著提高育种效率。利用这一方法,以长江流域推广品种泗棉3号为轮回亲本,山西9424和7235品系分别为抗虫基因和优质QTL的供体亲本,进行分子标记辅助的优质QTL系统选择和外源Bt基因的表型及分子选择。在(泗棉3号×7235)BC1F4中获得遗传背景与泗棉3号相近,株型稳定,且具有优质QTL的高强株系,在(泗棉3号×转Bt品系9424)BC4F1中获得遗传背景与泗棉3号相近,抗棉铃虫效果明显的单株。进一步通过高世代优质和抗虫目标株系的互交,分子标记辅助目标性状选择,目标基因纯合及稳定性检测,使高强纤维QTL和Bt基因快速聚合,培育出了优质、高产的抗虫棉新品系南农85188。
The modified backcross breeding method is a hybrid breeding and backcrossing method of hybrid lines that is used to improve the breeding of multiple excellent traits of cotton. With the increasing use of molecular markers in breeding selection, a modified backcross polymerization breeding method using molecular marker-assisted selection has been proposed. It is a combination of modified backcross breeding and molecular marker-assisted selection breeding with the production of up-to-date or soon-to-be-promoted varieties and the selection of genes or QTLs with the genetic background and breeding target traits of recurrent parents Significantly improve breeding efficiency. Using this method, the elite QTL cotton cultivar Shamian 3 was used as the reincarnating parent for the extension of the Yangtze River Basin. Shanxi Q2494 and 7235 were the parents of insect-resistant genes and QTLs for quality QTLs. The QTLs for molecular marker-assisted selection and the exogenous Bt genes Phenotype and molecular selection. A high-yielding line with similar genetic background to Simian No.3, stable plant type and high quality QTL was obtained from BC1F4 (Simian No.3 × 7235) BC4F1 (Simian No.3 × Bt strain 9424) The background is similar to that of Simian No.3, and the effect of cotton bollworm is obvious. Further, high-quality and high-yield resistant insect pests were developed through the crossbreeding of high-quality and insect-resistant target lines, the selection of molecular marker-assisted target traits, the homozygosity and stability detection of target genes, and rapid polymerization of QTLs and Bt genes of high-strength fibers Cotton new line Nannong 85188.