【摘要】 以250个代表性水稻品种和一个籼粳交(巴利拉/南京11)DH群体为材料,研究了直链淀粉含量在不同生态型品种间的变异,以及不同品种Wx基因座不同基因型与直链淀粉含量之间的关系。结果表明,在供试的250个水稻品种中直链淀粉含量存在着明显差异,分布在9.2%~29.2%之间;用AccⅠ-PCR标记对这些品种和DH群体Wx基因座基因型的检测表明,在200个籼稻品种中有151个品种带有等位基因Wxa,有49个品种带有等位基因Wxb;在供试的50个粳稻品种中绝大多数带有等位基因Wxb,只有7个品种例外。进一步对250份品种和DH群体的Wx基因的遗传效应分析表明,带有Wxa和Wxb等位基因的品种直链淀粉含量的平均值分别为11.4%~14.01%和23.6%~25.1%,Wx基因对直链淀粉含量的贡献率在77.9%~91.4%之间;在Wx位点上具有相同基因型的不同品种间,直链淀粉含量仍存在较大的变异,变幅达10个百分点左右。因此,稻米直链淀粉含量主要受Wx基因控制外,同时还受到其他基因的影响。文中讨论了稻米直链淀粉含量改良的可行策略。更多还原

【Abstract】 Amylose content is one of the key determinants to rice grain quality.In order to explore the variation in amylose content,250 varieties collected from different areas(Table 1) and a double haploid(DH) population,derived from a cross between the indica rice cv.Nanjing 11 and the japonica rice cv.Balilla,were investigated.The genotypes at Wx locus were detected using a molecular marker AccⅠ-PCR for each variety tested.The results showed among 200 varieties of indica rice,151 varieties carried the allele Wx~a while 49 varieties the allele Wx~b at the Wx locus.On the other hand,most varieties of japonica rice carried the Wx~b with 7 exceptions among 50 japonica varieties investigated. Amylose content of the 250 varieties varied from 9.2% to 29.2%;amylose content of varieties with the Wx~b and Wx~a was 9.2%19.0% and 17.5%29.2%,respectively, and their average value of amylose content was 14.0% and 23.6%,respectively.Amylose content of the DH lines varied from 8.4%28.3%;amylose content of the lines with the Wx~b and Wx~a was(8.4%)17.7% and 19.4%28.3%, respectively, and their average value of amylose content was 14.0% and 25.1%,respectively.The results above showed that there existed a variety that met demand of market for AC among varieties with both the Wx~b and Wx~a.Furthermore,by analyzing effect of the Wx gene on AC,the Wx gene contributed 77.9% to variation for AC based on the 250 varieties and contributed 91.4% to variation for AC based on the DH lines.However,variations in amylose content among the varieties with the same genotype at the Wx locus(Wx~aWx~a or Wx~bWx~b) were also existed.It was confirmed that amylose content was mainly controlled by the Wx gene and modified by other minor genes.Therefore,in the process of rice quality improvement,the appropriate allele at Wx locus should be firstly considered according to breeding program,then amylose content of candidate individual in higher generation would be evaluated due to effect of some minor genes to the rice qualities.更多还原