利用分子标记技术降低协优57的直链淀粉含量

 为克服产量高、适应性广的中籼组合协优57的直链淀粉含量较高、蒸煮食味品质较差的缺点，对其父母本较高的直链淀粉含量特性进行了改良。先前利用PCR AccⅠ分子标记辅助选择对其父本057进行改良，育成了直链淀粉含量改良型057, 简称057(TT)。本研究以ND42为优质基因的供体，利用PCR AccⅠ分子标记对协青早B\母本协青早A的保持系，简称协青早B(GG)\]进行改良，得到直链淀粉含量改良型协青早B，简称协青早B(TT)。然后用改良前、后的各亲本分别配组，分析各组合的基因型(GG、GT、TT)和食味品质。结果表明，改良单亲的GT型组合协青早B(GG)/057(TT)、协青早B(TT)/057(GG)杂交稻米的直链淀粉含量由原组合协青早B(GG)/057(GG)的26.1%分别降到19.3%和19.2%，但均一性较差。改良双亲的TT纯合型组合协青早B(TT)/057(TT)的杂交稻米，不仅直链淀粉含量降到中等偏低水平(12.5%)、胶稠度变得更软，而且直链淀粉含量的均一性也有了很大的提高。

Reducing Amylose Content of Hybrid Rice Xieyou 57 by Molecular Marker-Assisted Selection

To lower the high amylose content of hybrid rice Xieyou 57 (Xieqingzao A/057), Xieqingzao B (the maintainer line of Xieqingzao A) was used as recurrent parent and crossed with a donor parent with low amylose content. PCR Acc Ⅰ molecular marker was applied during backcross to identify three Wx genotypes, i.e. GG, GT and TT. Then the genotypes, the amylose contents and agronomic traits of the four combinations, Xieqingzao B(GG)/057(GG), Xieqingzao B(GG)/057(TT), Xieqingzao B(TT)/057(GG), Xieqingzao B(TT)/057(TT) were detected, respectively. The amylose contents of the hybrids with heterozygous GT Wx, i.e. Xieqingzao B(GG)/057(TT) and Xieqingzao B(TT)/057(GG) is 19.3% and 19.2% respectively, lower than that of Xieqingzao B(GG)/057(GG)(26.1%). The amylose contents of different seeds in the two hybrids with heterozygous GT Wx differed greatly.The combination of Xieqingzao B(TT)/057(TT) with homozygous TT Wx not only showed a decreased amylose content(12.5%) accompanied by increased gel consistency, but also had an improved uniformity in amylose contents among different seeds.