光合作用是植物的唯一能量来源, 剑叶是水稻开花后进行光合作用的主要部位。Ghd7是一个多效性产量基因, 能显著提高水稻产量。为了研究Ghd7对水稻剑叶形态的遗传效应, 文章利用一个包含190个家系的BC2F2群体对水稻剑叶长度(FLL)、剑叶宽(FLW)和剑叶面积(FLA)进行QTL定位分析。在BC2F2群体, FLL、FLW和FLA性状表型值均显示为双峰分布, 符合孟德尔单基因分离比, 并均与每穗实粒数呈现显著正相关。在第7染色体上RM3859和C39分子标记间定位到FLL、FLW和FLA的 QTL, 分别解释变异的73.3%、62.3%和71.8%, 均与Ghd7共分离。以珍汕97为轮回亲本, 特青和明恢63分别为供体亲本, 获得两个Ghd7近等基因系NIL(MH63)和NIL(TQ), FLL、FLW和FLA表型值均比珍汕97显著提高。另外, 超表达Ghd7的合江19转基因植株的FLL、FLW和FLA表型值分别比合江19增加了8.9 cm、0.5 cm和17.8 cm2。这些结果表明Ghd7对调控剑叶面积起重要作用。
Photosynthesis is the unique source of energy for plant. Flag leaf contributed the majority of photosynthate after rice flowering. Ghd7 is a pleiotropic gene, which can significantly increase rice production. In order to study the genetic effects of Ghd7 on the flag leaf morphology, we made quantitative trait locus (QTL) analysis for flag leaf length (FLL), flag leaf width (FLW), and flag leaf area (FLA) using a Ghd7-BC2F2 popu-lation of 190 plants. In the BC2F2 population, the frequency distribution of FLL, FLW, and FLA were bimodal and in agreement with single Mendelian segregation ratio (3:1). FLL, FLW, and FLA were positively correlated with grains per panicle in the population. One QTL was mapped to the interval between markers RM3859 and C39 on chromosome 7, which explained 73.3%, 62.3%, and 71.8% of the variations for FLL, FLW, and FLA, and co-segregated with Ghd7. Two near-isogenic lines of NIL (mh7) and NIL (tq7) were developed using Zhenshan 97 as the recurrent parent and Minghui 63 and Teqing as the donor parent, respectively. Both NILs significantly increased the phenotypic values of FLL, FLW, and FLA as compared with Zhenshan 97. FLL, The values of FLW and FLA for Ghd7 over-expression transgenic plants were 8.9 cm, 0.5 cm, and 17.8 cm2 larger than its recipient Hejiang 19. These results demonstrated that Ghd7 plays an important role in controlling the flag leaf area in rice.
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