Deciphering the change in root system architectural traits under limiting and non-limiting phosphorus in Indian bread wheat germplasm

Abstract

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.

Genome-wide association studies reveal putative QTLs for physiological traits under contrasting phosphorous conditions in wheat (Triticum aestivum L.)

“…In the present study HDCSW18, a wheat variety of very high yield potential and specifically bred for conservation agriculture conditions, exhibits very high phosphorus limitation tolerance largely because of its strong root traits. This genotype because of its strong RSA traits (Dharmateja et al, 2021) has the inherent ability to explore even the deeper layers of soil. Our study clearly shows that better P uptake though, largely depends Frontiers in Genetics frontiersin.org upon root traits, and is essential for better ground coverage and C assimilation but can improve PUE up to a limited extent because of the limitation imposed by PUtE.…”

“…Among the various management practices for the rational use of P, the development of P use efficient crop cultivars which come with no additional costs (Heuer et al, 2017) is the most economical. Moreover, for wheat, with the largest area and comparatively lower P utilization rate (10.7%) than rice (13.1%) and maize (11%) (Ma et al, 2011), focuses on the fast-track approaches to identify P efficient cultivars is very essential (Dharmateja et al, 2021). Productivity gains with low P-application by growing P-efficient cultivars would pave the way to meet future global food requirements in an eco-friendly, economically feasible, and socially sustainable manner.…”

Exploring root architecture and rhizosphere biology in fourteen winter wheat varieties released in Chile from 1965 to 2020

“…This, in turn, enhances root exploration and leads to better nutrient absorption (Bünemann et al 2018;Kuzyakov et al 2000). However, this rhizosphere biological activity can increase or decrease depending on the nutritional needs of crop phenological stages (Wang et al 2017) which are closely related to root development and growth (Dharmateja et al 2021).…”

Indian Wheat Genomics Initiative for Harnessing the Potential of Wheat Germplasm Resources for Breeding Disease-Resistant, Nutrient-Dense, and Climate-Resilient Cultivars

“…Not only agronomic practices but also breeding plays an important role in improving nutrient-use efficiency. As a result, nutrient-use efficient lines/varieties can be developed by modifying root architecture, stem phenology, and leaf phenology ( Dharmateja et al, 2021 ). The variable germplasm with miscellaneous structures, viz., deep root systems, enormous taproots, and the diverse shapes of roots previously adopted to low nutrient soil needs to be assessed under highly precise and uniform conditions.…”