利用Wx基因功能性标记选育中等直链淀粉含量优质水稻保持系

Developing indica maintainer lines with intermediate amylose content by Wx functional microsatellite marker in rice

利用Wx基因功能性标记484/485"对国内13份籼型保持系进行多态性鉴定和筛选.结果显示:检测出的Wx基因型与本品种直链淀粉含量(AC)有良好的对应关系;利用484/485"标记对Ⅱ-32B/宜香1B"配组后代(F1～F3代)进行PCR鉴定的结果表明,484/485"标记与稻米直链淀粉含量是紧密连锁、共分离的,经F2代分子辅助选择,F3代株系的484/485"Ⅰ型系比例高达93.5%,在F3代获得较多484/485"Ⅰ型株系的基础上,结合株型、粒型、垩白度、透明度、糊化温度等多项指标的田间和室内选择,于F6代获得了114份484/485"为Ⅰ型,且株型良好、粒型细长、低垩白、高透明度、低糊化温度的优质株系,其中,有92.1%入选系的直链淀粉含量在15%～20%之间;进一步测交鉴定还表明,这批入选优质株系有74.5%为保持系.说明利用484/485"标记辅助选择、高效改良或选育中等直链淀粉含量的优质保持系(或不育系)是可行的.

Genotypes of the 13 indica maintainer lines were detected by the Wx gene functional microsatellite marker ＂484/485＂.The results showed that there was significant association between the Wx genotypes and amylose contents of rice.Analysis of progenies in the generations F1 to F3 derived from ＂Ⅱ-32B/Yixiang 1B＂ confirmed that ＂484/485＂ microsatellite marker was tightly linked to and co-segregated with rice amylose content.After carrying out marker-assisted selection in F2 generation,individual plants with the homozygous Wx-Ⅰgenotype selected from F3 generation reached as high as 93.5%.The phenotypes such as plant type,grain shape,chalkiness,transparency,gelatinization temperature,etc.were characterized either in the field or in the lab.Finally,a total of 114 target breeding lines with Wx-Ⅰgenotype,good plant types,slender grain type,low degree of chalkiness,high degree of transparency,intermediate gelatinization temperature and amylose contents were successfully obtained from the F6 generation.Ninety-two point one percent of the breeding lines had the amylose contents between 15% and 20%.Results of testcross showed that 74.5% of the breeding lines were maintainer lines.It is suggested that developing indica maintainer lines with intermediate amylose contents by Wx microsatellite marker is feasible and effective.