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为培育食味品质优良、综合丰产性好的粳稻新品种,本研究以高产粳稻品种武香粳 14 作母本,以食味品质优良粳稻品种关东 194(含有控制低直链淀粉含量和暗胚乳的突变基因 Wx-mq)作父本配制杂交组合。通过比较 Wx-mq 与其位于第 6 染色体上的等位基因 Wx-b,Wx-a,wx 的 DNA 序列,发现 Wx-mq 基因的外显子 4 和外显子 5 上存在两个碱基突变,外显子 4 上的 G-A 突变产生了 NIaⅢ的酶切位点,并设计合成了能区分含或不含 Wx-mq 纯合基因型和杂合基因型的 CAPS 标记。利用该标记对武香粳 14/ 关东 194 衍生的 F5、F6株系进行辅助选择,筛选含 Wx-mq 纯合基因型的单株。成熟后对胚乳淀粉性质的调查结果与分子检测结果完全一致,分子标记辅助选择效果达 100%。这样我们就成功培育了食味品质优良、综合丰产性好的粳稻新品种南粳 46。
In order to cultivate a new japonica rice variety with good eating quality and comprehensive high yield, a japonica rice variety Wuxingjing 14 with high yielding japonica as female parent and Qainong 194 with high eating quality (containing low amylose content control and dark endosperm mutation Gene Wx-mq) was used as a male parent to prepare a crosses. By comparing the DNA sequence of Wx-mq with its alleles Wx-b, Wx-a, and wx on chromosome 6, two base mutations were found in exon 4 and exon 5 of the Wx-mq gene , GA mutation in exon 4 generated NIa Ⅲ restriction sites and designed and synthesized a CAPS marker capable of distinguishing between homozygous and non-Wx-mq genotypes and heterozygous genotypes. The marker-assisted selection of F5 and F6 derived from WuXiangJing 14 / Kantong 194 was used to screen individuals with Wx-mq homozygous genotypes. After maturation, the results of starch characterization of endosperm were completely consistent with the results of molecular detection, and the molecular marker-assisted selection effect was 100%. In this way, we successfully cultivated Nanjing 46, a new japonica rice with good eating quality and comprehensive high yield.