Yang Mengjiao, Wang Cairong, Hassan Muhammad Adeel, Li Faji, Xia Xianchun, Shi Shubing, Xiao Yonggui, He Zhonghu
Institute of Crop Sciences, National Wheat Improvement Centre, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100081, China.
Agricultural Research Institute of Yili, Yili, 835000, Xinjiang, China.
BMC Genomics. 2021 Mar 11;22(1):174. doi: 10.1186/s12864-021-07425-4.
Phosphorus (P) is an important in ensuring plant morphogenesis and grain quality, therefore an efficient root system is crucial for P-uptake. Identification of useful loci for root morphological and P uptake related traits at seedling stage is important for wheat breeding. The aims of this study were to evaluate phenotypic diversity of Yangmai 16/Zhongmai 895 derived doubled haploid (DH) population for root system architecture (RSA) and biomass related traits (BRT) in different P treatments at seedling stage using hydroponic culture, and to identify QTL using 660 K SNP array based high-density genetic map.
All traits showed significant variations among the DH lines with high heritabilities (0.76 to 0.91) and high correlations (r = 0.59 to 0.98) among all traits. Inclusive composite interval mapping (ICIM) identified 34 QTL with 4.64-20.41% of the phenotypic variances individually, and the log of odds (LOD) values ranging from 2.59 to 10.43. Seven QTL clusters (C1 to C7) were mapped on chromosomes 3DL, 4BS, 4DS, 6BL, 7AS, 7AL and 7BL, cluster C5 on chromosome 7AS (AX-109955164 - AX-109445593) with pleiotropic effect played key role in modulating root length (RL), root tips number (RTN) and root surface area (ROSA) under low P condition, with the favorable allele from Zhongmai 895.
This study carried out an imaging pipeline-based rapid phenotyping of RSA and BRT traits in hydroponic culture. It is an efficient approach for screening of large populations under different nutrient conditions. Four QTL on chromosomes 6BL (2) and 7AL (2) identified in low P treatment showed positive additive effects contributed by Zhongmai 895, indicating that Zhongmai 895 could be used as parent for P-deficient breeding. The most stable QTL QRRS.caas-4DS for ratio of root to shoot dry weight (RRS) harbored the stable genetic region with high phenotypic effect, and QTL clusters on 7A might be used for speedy selection of genotypes for P-uptake. SNPs closely linked to QTLs and clusters could be used to improve nutrient-use efficiency.
磷（P）对于确保植物形态建成和籽粒品质至关重要，因此高效的根系对于磷吸收至关重要。鉴定苗期根系形态和磷吸收相关性状的有用位点对小麦育种很重要。本研究的目的是利用水培法评估扬麦16/中麦895衍生的双单倍体（DH）群体在苗期不同磷处理下根系结构（RSA）和生物量相关性状（BRT）的表型多样性，并使用基于660K SNP芯片的高密度遗传图谱鉴定QTL。
所有性状在DH系间均表现出显著变异，具有较高的遗传力（0.76至0.91），且所有性状间具有较高的相关性（r = 0.59至0.98）。完备复合区间作图（ICIM）鉴定出34个QTL，单个QTL解释的表型变异为4.64%-20.41%，对数似然比（LOD）值范围为2.59至10.43。7个QTL簇（C1至C7）定位在3DL、4BS、4DS、6BL、7AS、7AL和7BL染色体上，7AS染色体上的簇C5（AX-109955164 - AX-109445593）具有多效性，在低磷条件下对调节根长（RL）、根尖数（RTN）和根表面积（ROSA）起关键作用，其有利等位基因来自中麦895。
本研究在水培条件下基于成像流程对RSA和BRT性状进行了快速表型分析。这是在不同养分条件下筛选大群体的有效方法。在低磷处理中鉴定出的6BL（2个）和7AL（2个）染色体上的4个QTL表现出由中麦895贡献的正向加性效应，表明中麦895可作为缺磷育种的亲本。根干重与地上部干重比（RRS）最稳定的QTL QRRS.caas-4DS包含具有高表型效应的稳定遗传区域，7A染色体上的QTL簇可用于快速选择磷吸收基因型。与QTL和簇紧密连锁的SNP可用于提高养分利用效率。
