分子标记辅助改良杂交稻协优57及其父母本的蒸煮食味品质

协优57是一个产量高和适应性强的杂交中籼组合,但由于其父母本直链淀粉含量（AC）高,导致杂交稻米的AC较高、蒸煮食味品质较差。先前利用PCR-AccⅠ分子标记辅助选择对协优57的亲本057恢复系,记作057（GG）]和协青早A不育系,记作协A（GG）]的W x基因进行改良。利用改良前、后的各亲本分别配组,分析不同组合的AC、食味品质和颗粒性淀粉结合酶（GBSS）活性。结果表明,改良单亲的GT型组合协A（GG）×057（TT）、协A（TT）×057（GG）杂交稻米的AC由原组合协A（GG）×057（GG）的28%分别降到19.9%和19.3%,但均一性较差。改良双亲的TT纯合型组合协A（TT）×057（TT）的杂交稻米,不仅AC降到中等偏低水平（13.1%）,而且AC的均一性也有了很大的提高,蒸煮食味品质明显改善。GBSS活性分析表明：三种W x基因型的GBSS活性总体表现为GG〉GT〉TT。

Improvement of the cooking and eating quality of hybrid rice Xieyou 57 and its parents by molecular marker-assisted selection

Xieyou 57,an elite indica hybrid between the male-sterile line Xieqingzao A and the restorer line 057,owns high yield and wide adaptability.The high amylose content（AC） in the endosperm of both parents relatively results in poor cooking and eating quality of the hybrid.057（the restorer line,designated as 057（GG）） and XieqingzaoA（the male-sterile line,designated as XA（GG）） on Wx gene was improved.The AC eating quality and granule-bound starch synthase（GBSS） activity of all the four combinations were analyzed.The results revealed that the AC of the single parent improved hybrids,Xieqingzao A（GG） 057（TT） and Xieqingzao A（TT） 057（GG） were 19.9% and 19.3%,respectively.Both were lower than that of original Xieyou 57（GG,26.2%）.Result indicated that the improved line of hybrid with homozygous TT-Wx-Xieqingzao A（TT）×057（TT）,not only showed a decreased AC（12.5%）,but also had better uniform AC for different seeds and good cooking and eating quality.The GBSS activity was tightly related to AC,and the three Wx genotype showed GGGTTT.