【作者】 孙业盈；

【导师】 邓晓建；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2005， 硕士

【摘要】 直链淀粉含量（AC）、胶稠度（GC）和糊化温度（GT）是衡量稻米蒸煮与食用品质的3项重要指标。普遍认为稻米AC是由位于水稻第6染色体短臂的Wx基因控制,同时并受一些微效基因的影响。目前,关于水稻Wx基因与稻米AC、GC和GT的遗传关系的报道还存在着一些争论。研究Wx基因与AC、GC和GT的遗传关系,不仅有利于探讨GC和GT的遗传机制,而且对提高稻米蒸煮与食用品质有一定的帮助。 本文一方面运用PCR-Acc Ⅰ分子标记检测实验材料的Wx基因型,同时测定它们的AC、GC和GT,探讨了水稻Wx基因与稻米AC、GC和GT的遗传关系;另一方面,对田间育种的中间株系进行全面的品质性状分析,并结合PCR-Acc Ⅰ分子标记和遗传背景分析的方法,为育种材料的最后决选提供可靠依据。主要结果如下: 1.以60个籼稻品种（或品系）和57个（G46B/D香1B）B₃F₅株系为材料,研究结果表明AC与GC呈极显著负相关,在两组材料中二者的相关系数达到了-0.836和-0.906,且二者均与Wx基因型密切相关,Wx基因为GG型的材料具有较高的AC和较硬的GC,而TT型的材料具有中等的AC和较软的GC。因为已知稻米AC主要由Wx基因控制,上述结果暗示了稻米GC也可能主要由Wx基因或与其紧密连锁的基因位点控制。 2.在全部57个B₃F₅代株系中,26个GG型株系的AC为20.4%-27.0%,平均值为24.9%,GC为25-31mm,平均值为27mm,而31个TT型株系的AC为10.8%-13.4%,平均值为11.8%,GC为46-77mm,平均值为57mm,可见GG型Wx基因始终对应着高AC和硬GC,TT型Wx基因始终对应着中等AC和软GC,没有发现重组株系,AC的高低和GC的硬软与Wx基因型存在共分离现象,这表明AC主要由Wx基因控制,GC也由Wx基因或与其紧密连锁的基因位点控制。 3.在60个籼稻品种中,稻米GT与稻米AC和品种Wx基因型均没有明显的相关性,不同AC的品种和不同Wx基因型的品种,GT有高的也有低的,分布范围大致相同。如按Wx基因型分类,21个GG型供试品种的GT为3.3-7.0,平均值为4.9,而39个TT型供试品种的GT为3.0-7.0,平均值为5.2。由此,可以推断控制GT的基因位点不是Wx基因位点。 4.利用PCR-Acc Ⅰ分子标记检测了37个育种中间株系的Wx基因型,并且综合更多还原

【Abstract】 Amylose content(AC), gel consistency(GC) and gelatinization temperature(GT) are three important aspects that evaluate the cooking and eating quality of rice. It is generally considered that AC is controlled by Wx gene, located at the short arm of chromosome 6 in rice. At the same time some minor genes also influenced AC. At present time, there is some debate about genetic relationship among Wx gene, AC, GC and GT of rice. Studies on the genetic relationship among Wx gene, AC, GC and GT of rice not only make for exploring the genetic mechanism of GC and GT but also help to improve the cooking and eating quality of rice.We tested the Wx genotype by the PCR-Acc I molecular marker and investigated AC, GC and GT of our experiment material to explore the genetic relationship among Wx gene, AC, GC and GT of rice. On the other hand, we analyzed quality traits of some breeding lines comprehensively. The VCR-Acc I molecular marker and the way of genetic background’s analysis were also used in the course. The result would offer reliable data for selecting breeding material finally. The major results are as follows:1. By testing Wx genotype and investigating amylose content (AC), gel consistency (GC) and gelatinization temperature (GT) of 60 indica varieties (or lines) and 57 B3F5 breeding lines of G46B/D Xiang 1B , the genetic relationship among Wx gene, AC, GC, and GT of rice was analyzed. The results showed that there were significant negative correlations between AC and GC, with -0.836 and -0.906 of correlation coefficients in the two groups material, respectively. Moreover, both of AC and GC were closely related to Wx genotypes, i.e. the materials with GG-type of Wx gene had higher AC and harder GC, however, the materials with TT-type of Wx gene had moderate AC and softer GC. Because it was true that the AC of rice grain was controlled by Wx gene. So the result indicated that GC would be controlled by Wx gene or by one locus tightly linked to this gene.2. In all 57 B3F5 lines, AC ranged from 20.4% to 27.0% with the mean value of 24.9% and GC from 25mm to 31mm with the mean value of 27mm in 26 lines with GG-type of Wx gene, however, AC ranged from 10.8% to 13.4% with the mean value of 11.8% and GCfrom 46mm to 77mm with the mean value of 57mm in 31 lines with TT-type of Wx gene. So the GG-type of lines always had high AC and hard GC, the TT-type of lines always had moderate AC and soft GC, and no recombiant lines were found. In other words high or low AC and hard or soft GC were cosegregated with Wx genotypes. These results suggested that AC was mainly controlled by Wx gene and GC was also controlled by Wx gene or by one locus tightly linked to this gene.3. GT was not significantly related to AC and Wx genotype in 60 indica varieties. For the varieties that had different AC or Wx genotypes, the range of GT was the same on the whole. For example, according to Wx genotypes, GT of 21 varieties with GG-type of Wx gene ranged form 3.3 to 7.0 with the mean value of 4.9, however, GT of 39 varieties with TT-type of Wx gene ranged from 3.0 to 7.0 with the mean value of 5.2. So it was inferred that the locus controlling GT was not Wx locus.4. The Wx genotype of 37 breeding lines was tested by PCR-Acc I molecular marker. At the same time, their quality traits were also analyzed comprehensively. Among them, we selected 14 lines that not only had homozygous Wx genotype but also excellent milling quality and appearance quality.5. 16 B3F5 lines and 5 BjFg lines were selected from the 37 breeding lines and their genetic background were analyzed by 40 polymorphic SSR primers that were selected from 324 SSR primers distributing all chromosomes of rice. The result showed that the average genetic similarity index with G46B was 90.0% in the 16 B3F5 lines, among which the highest was 98.8%, and 66.7% in the 5 BiF8 lines, among which the highest is 76.3%.6. Based on the above-mentioned results, we screened out several breeding lines i.e. the No.25, No.26, No.29 and No.30 lines that had better quality traits than G46B and higher genetic similarity index with G46B.更多还原