以利用农杆菌介导glgC-TM基因而获得的水稻优质晚粳品种中超123Ts代纯系作为葡萄糖焦磷酸酶(ADP—glucose pyrophosphorylase,AGP)基因的供体亲本,与营养功能粳稻品种巨胚1号为酽基因供体亲本进行杂交。通过单株稻米籽粒胚性状的形态观察并结合分子标记检测,在64个F4代候选株系中共筛选到16个同时带有glgC-TM/ge双基因的聚合株系。对其中综合性状较好、籽粒大的5个株系种子分别进行胚重、米质理化指标和γ-氨基丁酸(GABA)含量的测定。与AGP基因的供体亲本中超123相比,5个含glgC-TM/ge双基因聚合株系稻米的百粒胚重最小增幅为70.2%,最大增幅为119.0%,达极显著水平;GABA含量的增加幅度为102.93%~194.14%。所选株系的千粒重均超过巨胚1号,差异达极显著水平;而稻米的胶稠度、碱消值和直链淀粉含量等品质指标的变化不很明显。偏籼型的glgC-TM/ge聚合株系直链淀粉含量均显著高于双亲中超123和巨胚1号;而偏粳型的glgC-TM/ge聚合株系与双亲没有显著差异。研究结果表明,glgC-TM和驴基因在聚合株系稻米籽粒总淀粉的合成和胚的形成中都得到充分表达,增加了稻谷千粒重和米胚大小,但对直链淀粉的合成影响不大。认为利用生物技术与传统技术相结合的分子设计育种来调整稻米的营养功能结构和产量是一条行之有效的途径。
T5 pure lines of japonica rice variety Zhongchao 123 with glgC-TM gene mediated by Agrobacterium transformation, which were used as donor parent of AGP (ADP-glucose pyrophosphorylase) gene, were crossed with a nutritionfunctional japonica rice variety Jupei 1 with ge gene. Sixteen lines with genes glgC-TM/ge were screened from 64 lines in F4 generation by molecular marker and morphological observation on the seed embryo from single rice plant. The physicalchemical characteristics and γ-aminobutyric acid (GABA) content of rice grains were measured for the five F4 lines with good performance of multiple traits. The results showed that all the embryo weight per 100-seed from the five F4 lines were significantly higher than that of the parent Zhongchao 123 with an increase of 70.2% at least and 119.0% at most, and the GABA content of the five F4 lines increased by 102.93% to 194.14% compared with the parent Zhongchao 123. However, the eating quality characteristics such as gel consistency, alkali spreading value and amylose content had no obvious changes in the selected lines. The amylose contents of the indicaclinous F4 lines were significantly beyond the two parents while those of the japonicaclinous ones were close to the parents, which indicated that the genes glgC-TM and ge were both expressed in the process of starch synthesis and embryo development of grains, thus leading to the increase of 1000-grain weight and embryo size. Based on these results, the breeding by molecular design combining with bio-technology and traditional technology was considered as an effective way to improve the nutrition-functional fortification and rice grain yield.