大麦磷高效重要性状的QTL定位与遗传分析

Phosphorus (P) is one of the necessary macronutrients for plant growth. Soil P deficiency severely restricted the crop production due to its low availability to plants. Barley is grown all over the world as an important cereal crop and its production is ranked fifth in the world. Barley is widely used for animal feed and food industry. Previous researches have indicated that barley differed in P uptake and utilization among different genotypes. A genotype with high P efficiency (CN4027) was obtained in our previous study by screening 556 barley germplasm resources. Two populations of recombinant inbred lines (RILs) were developed between CN4027 and two different cultivars with low phosphorus efficiency. High P efficiency barley (CN4027) is used as the key material in our project to elucidate the contents as follows: 1) QTL mapping of P uptake and utilization characteristics will be analyzed during three growth stages to excavate the locus of high P efficiency by using the RILs of Baudin/CN4027; 2) QTL analysis of root morphology in barley with high P efficiency will be investigated to get a control locus of high P efficiency for root morphology by using the RILs of Baudin/CN4027; 3) The major QTL for of great phenotypic variance will be validated by using the RILs of Fleet/CN4027, for discussion on genetic mechanisms of high P efficiency in uptake and utilization.

磷是植物生长发育必需的营养元素之一，由于土壤中磷素的植物有效性低，土壤磷缺乏已经严重制约了作物产量。大麦是重要的谷类作物，其种植遍布世界各地，在作物产量中排名第五位，广泛应用于饲料及食品工业。研究表明，大麦具有磷吸收利用的基因型差异。课题组前期通过556份大麦种质资源的收集与磷效率鉴定，获得一份磷高效基因型大麦种质材料CN4027，并使用其与两个磷低效栽培品种杂交，成功创制了两个重组自交系群体。本项目将以磷高效基因型CN4027为核心材料，(1)利用RIL群体Baudin/CN4027，进行三个生育期的磷吸收利用特征QTL分析，发掘磷高效吸收利用QTL位点；(2)使用RIL群体Baudin/CN4027，进行磷高效根系形态QTL分析，找到有利于磷高效根系形态的控制位点；(3) 通过RIL群体Fleet/CN4027，对表型变异度大的主效QTL位点进行验证，揭示磷高效吸收利用稳定遗传机理。

磷是植物生长发育必需的营养元素之一，由于土壤中磷素的植物有效性低，土壤磷缺乏已经严重制约了作物产量。大麦是重要的谷类作物，其种植遍布世界各地，在作物产量中排名第五位，广泛应用于饲料及食品工业。本项目在前期收集不同生态地理来源的栽培和野生大麦种质资源，进行磷效率特性鉴定与筛选的基础上，以磷高效基因型大麦为核心材料，进行QTL定位与遗传分析，主要结果如下：（1）以群体Baudin/CN4027 RIL F8为作图群体，构建了一幅DArT标记遗传图谱，覆盖了7条染色体上的1148.7cM区域，平均标记距离为1.89cM；（2）以无机磷（Pi）和有机磷（Po）为磷源，分别设置低磷和正常供磷处理，进行了大麦苗期群体磷效率相关性状表型鉴定及QTL分析，检测到大麦苗期和成熟期QTL位点共计26个；（3）对群体根系形态进行分析，发掘低磷和正常供磷下根系形态相关QTL位点31个，并明确了根系形态与磷高效之间的遗传关系；（4）对于染色体3H上的一个磷利用效率新主效基因位点Qpue.sau-3H，解释表型变异度在12.5%-30.7%之间，通过协方差分析和群体Fleet/CN4027 RIL F8验证，都证明其具有磷利用效率的遗传稳定性，具有精细定位和图位克隆等深入研究的价值；（5）新开发的两个大麦寡核苷酸探针Oligo-HvT01、Oligo-442A01，与主效QTL紧密连锁的分子标记Hvc316等已应用于染色体鉴定与分子标记辅助选择新材料，具有良好的应用前景。