穗长是影响水稻产量的重要因子之一,是典型的数量性状,遗传基础复杂,且易受环境等因素的影响。染色体单片段代换系(Chromosome single segment substitution lines,CSSSLs)减少了个体间遗传背景的干扰,是鉴定复杂性状QTL的新型遗传材料。本研究以广陆矮4号为受体、日本晴为供体的85个染色体单片段代换系群体为试验材料,通过单因素方差分析和Dunnett's多重比较测验单片段代换系与受体亲本广陆矮4号之间穗长的差异,对代换片段上穗长QTL进行了鉴定。以P<0.001为阈值,共检测到22个穗长QTLs,分布于除第10染色体以外的11条染色体上,其加性效应值的变化范围为-2.63～3.87,加性效应百分率变化范围为-11.47%～16.88%。这些QTLs的鉴定,为进一步克隆穗长QTL以及水稻穗长的分子改良提供了重要的依据。
Grain weight, one of the major factors determining rice yield, is a typical quantitative trait control ed by multiple genes. With Guangluai 4 as recipient and Nipponbare as donor, a population of 119 chromosome single segment substitution lines had been developed. Correlation analysis between grain weight and grain shape by SPSS revealed that 1 000-grain weight shared extremely significant posi-tive correlation with grain length and length-width ratio, but no significant correlation with grain width and thickness. The QTL analysis of grain weight was carried out using one-way analysis of variance and Dunnett＇s test. Nineteen stable QTLs re-sponsible for grain weight were identified over two years. Al 19 QTLs were identi-fied on al chromosomes except for chromosome 10 and 12 at a significance level of P≤0.001. Among them, 10 QTLs had a positive effect and were derived from the Nipponbare al ele, the additive effect of these QTLs ranged from 0.49 to 2.74 g, and the contributions of the additive effects ranged from 2.00% to 11.05%. Another 9 QTLs had a negative effect and were al derived from Guangluai 4 al ele, the ad-ditive effect of these QTLs ranged from 0.60 to 2.35 g, and the contributions of the additive effects ranged from 2.40% to 9.84%. The results provide a basis for the fine mapping and gene cloning of novel locus associated with rice grain weight.
在水稻品种南粳41中发现了一个黄绿叶自然突变体,经过多代连续自交形成了稳定的突变系,命名为ygl11（t）,ygl11（t）整个生育期叶片都表现为黄绿色。对苗期、分蘖盛期、齐穗期突变体和野生型的叶绿素含量进行测定,ygl11（t）的叶绿素含量是野生型的45.7%~74.7%,叶绿素a含量是野生型的55.2%~87.5%,叶绿素b含量是野生型的12.5%~25.3%,ygl11（t）的类胡萝卜素的含量是野生型的62.3%~97.0%。ygl11（t）在分蘖盛期的净光合速率显著高于野生型,花后10d,ygl11（t）的净光合速率比野生型略低。对突变体叶片中叶绿体的超微结构进行观察,发现突变体叶绿体内的类囊体基粒片层数目减少且严重扭曲变形。遗传分析表明,ygl11（t）叶色性状受1对隐性核基因控制。利用SSR分子标记将YGL11（t）初步定位在水稻第10染色体的长臂上,进一步利用新开发的InDel和CAPS标记将YGL11（t）定位在58.1kb的物理距离内。对该区段内存在的开放阅读框进行序列分析,发现突变体ygl11（t）中编码叶绿素a氧化酶（chlorophyll a oxygenase 1）基因（OsCAO 1）的第9个外显子存在2个碱基缺失,从而导致提前出现终止密码子,初步分析OsCAO1即为YGL11（t）的候选基因。
