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本研究以优质稻品种佳辐占为供体亲本与轮回亲本Ⅱ-32B进行连续回交,采用选择回交导入法结合分子标记辅助选择技术和农艺性状选择,将粒长主效基因GS3及其他外观品质性状基因导入Ⅱ-32B中,获得4个外观品质得到明显改善的Ⅱ-32B改良株系。Ⅱ-32B改良株系的谷粒明显变得细长,粒长由原来的8.04 mm增加到8.99 mm,粒宽由3.02 mm降至2.85 mm,长宽比由原来的2.67提高到3.16。此外,垩白率和垩白度极显著降低,分别由原来的55.6%和14.3%降低至23.9%和4.6%。除千粒重极显著增加外,抽穗期、株高、有效穗、穗长、结实率等5个主要农艺性状差异不显著。通过遗传背景分析,4个改良株系的遗传背景回复率为90.7%~96.3%,其中GL2株系分别在第5和第6染色体存在一个位点未回复外,其他位点均回复,回复率达到96.3%。结果表明,采用分子标记辅助选择与田间表型选择相结合可较快速地改良杂交稻亲本的外观品质。
In this study, the high-quality rice varieties Jiafu accounted for the donor parent and the reincarnated parent Ⅱ-32B continuous backcross, the use of selective backcross induction method combined with molecular marker-assisted selection and agronomic traits selection, the grain length major gene GS3 and other The appearance quality trait gene was introduced into Ⅱ-32B, and four modified lines of Ⅱ-32B with obvious improvement of appearance quality were obtained. The grains of Ⅱ-32B improved obviously, the grain length increased from 8.04 mm to 8.99 mm, the grain width decreased from 3.02 mm to 2.85 mm, and the aspect ratio increased from 2.67 to 3.16. In addition, the chalkiness rate and chalkiness significantly decreased from 55.6% and 14.3% to 23.9% and 4.6% respectively. Except for the significant increase of 1000-grain weight, the five main agronomic traits such as heading date, plant height, effective ear, ear length and seed setting rate were not significantly different. Genetic background analysis showed that the genetic background response rates of the four improved lines ranged from 90.7% to 96.3%. Among GL4 lines, there was one locus on chromosomes 5 and 6, Reached 96.3%. The results showed that the combination of molecular marker-assisted selection and phenotypic selection in the field could improve the quality of hybrid parents more rapidly.