Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India.
Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India.
PLoS One. 2021 Oct 1;16(10):e0255840. doi: 10.1371/journal.pone.0255840. eCollection 2021.
The root system architectures (RSAs) largely decide the phosphorus use efficiency (PUE) of plants by influencing the phosphorus uptake. Very limited information is available on wheat's RSAs and their deciding factors affecting phosphorus uptake efficiency (PupE) due to difficulties in adopting scoring values used for evaluating root traits. Based on our earlier research experience on nitrogen uptake efficiency screening under, hydroponics and soil-filled pot conditions, a comprehensive study on 182 Indian bread wheat genotypes was carried out under hydroponics with limited P (LP) and non-limiting P (NLP) conditions. The findings revealed a significant genetic variation, root traits correlation, and moderate to high heritability for RSAs traits namely primary root length (PRL), total root length (TRL), total root surface area (TSA), root average diameter (RAD), total root volume (TRV), total root tips (TRT) and total root forks (TRF). In LP, the expressions of TRL, TRV, TSA, TRT and TRF were enhanced while PRL and RAD were diminished. An almost similar pattern of correlations among the RSAs was also observed in both conditions except for RAD. RAD exhibited significant negative correlations with PRL, TRL, TSA, TRT and TRF under LP (r = -0.45, r = -0.35, r = -0.16, r = -0.30, and r = -0.28 respectively). The subclass of TRL, TSA, TRV and TRT representing the 0-0.5 mm diameter had a higher root distribution percentage in LP than NLP. Comparatively wide range of H' value i.e. 0.43 to 0.97 in LP than NLP indicates that expression pattern of these traits are highly influenced by the level of P. In which, RAD (0.43) expression was reduced in LP, and expressions of TRF (0.91) and TSA (0.97) were significantly enhanced. The principal component analysis for grouping of traits and genotypes over LP and NLP revealed a high PC1 score indicating the presence of non-crossover interactions. Based on the comprehensive P response index value (CPRI value), the top five highly P efficient wheat genotypes namely BW 181, BW 103, BW 104, BW 143 and BW 66, were identified. Considering the future need for developing resource-efficient wheat varieties, these genotypes would serve as valuable genetic sources for improving P efficiency in wheat cultivars. This set of genotypes would also help in understanding the genetic architecture of a complex trait like P use efficiency.
根系结构（RSAs）在很大程度上通过影响磷的吸收来决定植物的磷利用效率（PUE）。由于采用评估根系特征的评分值存在困难，因此有关小麦 RSAs 及其决定磷吸收效率（PupE）的因素的信息非常有限。根据我们之前在水培和土壤盆栽条件下对氮吸收效率筛选的研究经验，在水培条件下对 182 个印度面包小麦基因型进行了综合研究，其中包括有限磷（LP）和非限制磷（NLP）条件。研究结果表明，在 LP 条件下，PRL、TRL、TRV、TSA、RAD、TRT 和 TRF 的表达增强，而 PRL 和 RAD 减少。在 LP 条件下，根长、总根长、总根表面积、根平均直径、总根体积、总根尖和总根叉等 RSA 性状均表现出显著的遗传变异、根性状相关性和较高的遗传力。除 RAD 外，两种条件下的 RSA 之间也存在几乎相似的相关性模式。在 LP 条件下，RAD 与 PRL、TRL、TSA、TRT 和 TRF 呈显著负相关（r = -0.45、r = -0.35、r = -0.16、r = -0.30、r = -0.28）。在 LP 条件下，0-0.5mm 直径的 TRL、TSA、TRV 和 TRT 亚类的根分布百分比高于 NLP。LP 中 H'值的范围较宽，即 0.43 至 0.97，表明这些性状的表达模式受 P 水平的影响很大。其中，RAD（0.43）在 LP 中表达减少，TRF（0.91）和 TSA（0.97）的表达显著增强。基于 LP 和 NLP 条件下对性状和基因型的分组的主成分分析显示，PC1 得分较高，表明存在非交叉相互作用。根据综合磷响应指数值（CPRI 值），鉴定出 5 个高磷效率小麦基因型，即 BW 181、BW 103、BW 104、BW 143 和 BW 66。考虑到未来开发资源高效小麦品种的需要，这些基因型将作为提高小麦品种磷效率的有价值的遗传资源。这组基因型也将有助于了解磷利用效率等复杂性状的遗传结构。
