Next Article in Journal
Effects of Nozzle Arrangement Strategies on Spray Uniformity in Soybean–Maize Intercropping
Next Article in Special Issue
Development of an Evaluation Indicator System for Medium–Low Yield Farmlands on the Basis of the Synergistic Improvement of Soil Carbon Sequestration and Production Capacity: A Theoretical Framework
Previous Article in Journal
Morphological Diversity and Crop Mimicry Strategies of Weedy Rice Under the Transplanting Cultivation System
Previous Article in Special Issue
Effect of Green Cowpea Manure on the Quality Properties of Sandy Soils Under the Specific Conditions of the Dry Climate in Romania
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Agronomy
Volume 15
Issue 4
10.3390/agronomy15040983
agronomy-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Response of Agronomic Traits and Phosphorus Uptake to Soil P Deficiency During Rice Cultivars Improvement

by
Chunqin Li
,
Xu Mo
,
Shuwei Li
,
Yuxi Liu
,
Rongxin Chen
,
Shuying Yu
,
Wenqiang Lin
,
Yifeng Wang
and
Yajun Hu
*
College of Agriculture, Hunan Agricultural University, Changsha 410128, China
*
Author to whom correspondence should be addressed.
Agronomy 2025, 15(4), 983; https://doi.org/10.3390/agronomy15040983
Submission received: 19 March 2025 / Revised: 11 April 2025 / Accepted: 17 April 2025 / Published: 19 April 2025
(This article belongs to the Special Issue Keeping Nutrients in the Soil: The Challenges, Benefits and Trade-Offs)
Browse Figures
Versions Notes

Abstract

:
Developing high phosphorus (P) efficient rice varieties is essential for sustainable phosphate resource conservation. This study evaluated 16 rice cultivars from four breeding eras: ancient (<1940), early conventional (1940–2000), modern conventional (2000–2020), and hybrid rice (2000–2020). Using pot experiments in low-P soil, we examined two P treatments: P0 (no P application, simulating low-P stress) and P50 (50 kg hm−1 P application, normal P input). We systematically compared agronomic traits, P distribution patterns, and P uptake efficiency across breeding generations. The result showed that modern breeding significantly increased root biomass, shoot biomass, and grain yield while reducing plant height. Low-P stress (P0) had minimal impact on growth traits but negatively affected P uptake, particularly plant P content and accumulation patterns. Under P0 treatment, modern conventional varieties maintained a higher stem P concentration (0.47–0.65 g·kg−1 vs. 0.27–0.49 g·kg−1 in hybrid varieties; 0.47–0.65 g·kg−1 vs. 0.18–0.28 g·kg−1 in ancient varieties, p < 0.05). P allocation strategies varied significantly across breeding eras. Root P accumulation ratios decreased from ancient to modern varieties, while modern conventional rice had the highest stem P storage (24.1–30.5%), and hybrid rice allocated the largest partition of 76.4–78.1% P to grains. Additionally, P uptake efficiency and P fertilizer productivity increased by 131.09% and 91.21% (p < 0.01) from ancient to modern conventional rice, with hybrids exhibiting the highest values for both parameters. Principal component analysis (PCA) revealed distinct trait clusters separating ancient, conventional, and hybrid rice based on the agronomic traits, P uptake, and rhizosphere soil parameters. Random forest analysis identified that, under low-P conditions, root P content was the strongest predictor of grain yield, whereas under normal P conditions, rhizosphere pH had the highest relationship to grain yield. These findings demonstrate that modern breeding has enhanced P adaptation through optimized root architecture and organ-specific P allocation strategies, which providing valuable insights for developing future P-efficient rice varieties.

1. Introduction

Phosphorus (P), a non-substitutable macronutrient, plays pivotal roles in crop growth and developmental processes [1]. In P-deficient soil, crops usually exhibit compromised metabolic functions, diminished stress resilience, and substantial grain yield reductions [2,3,4]. Soil P, due to its low mobility, often forms complexes with minerals such as iron, aluminum, and calcium, which leads to low availability in the rhizosphere [5]. Field observations reveal that seasonal P uptake efficiency in agricultural ecosystem rarely surpasses 10–25% under conventional agricultural management [6]. Prompting excessive fertilizer applications was usually conducted to achieve high grain yields. This not only disrupts nutrient balance but also contributes to environmental issues, such as water eutrophication [7,8]. Moreover, as P rock is a finite mineral resource, it is increasingly recognized as a diminishing nutrient element [9]. Therefore, improving soil P availability and use efficiency in agriculture is essential to ensure sustainable food production and minimizing environmental degradation.
P use efficiency (PUE) in plants is a concept that encompasses two complementary strategies to optimize P utilization. One strategy is P acquisition efficiency, which involves enhancing the mobilization of P in the rhizosphere and improving the plant’s ability to absorb it through its roots and rhizospheric microbes. This is particularly important in soils where P is bound to insoluble minerals. Root traits such as root architecture [10], root exudate production [11], and mycorrhizal associations [12] are key factors that influence the extent to which P can be accessed and absorbed by plants. A second strategy focuses on internal P utilization efficiency, which involves the optimized allocation of P within the plant and the efficient recycling of internal P during different growth stages. For example, during the early stages of plant growth, P is primarily utilized in the development of the root system and young leaves [13]. As the plant matures, internal P is reallocated to support the development of reproductive organs, such as flowers and seeds, which are crucial for maintaining yield. In P-limited conditions, some plants exhibit a preferential allocation of P to the root system to enhance nutrient uptake, while others may prioritize allocation to grains or seeds to ensure reproductive success. Additionally, the ability of plants to remobilize P from older tissues to younger, growing tissues during nutrient stress can help mitigate the effects of P deficiency.
Rice varietal improvement, defined as the systematic substitution of existing cultivars with genetically superior genotypes facilitated by breeding scientists and companies, has instigated quick shifts in rice production systems [14]. The historical progression from traditional tall rice cultivars to semi-dwarf conventional varieties, and subsequently to hybrid and super rice cultivars [15], reflects not only morphological advancements in cultivation but also artificial selection in responses to changing nutrient management practices. During the pre-green revolution era (pre-1940s), traditional rice varieties breeding did not consider P nutrition, which primarily depended on the mineralization of organic P pools in the infertile paddy soil. The green revolution period (1960s–1990s) was marked by concurrent improvements in yield potential and medium P fertilizer inputs through the introduction of dwarfing genes that improved lodging resistance and harvest indices [16,17,18]. Subsequent agricultural intensification in the post-2000s era saw the integration of high P fertilization regimens with hybrid rice technologies, establishing production systems that prioritized yield maximization [18,19,20]. Of particular concern is the historical paradigm of breeding programs; these selection processes, under the condition of gradually enrichment of soil P, may have systematically overlooked the genetic potential for both rhizospheric P acquisition and internal nutrient recycling mechanisms critical for sustainable cultivation. We hypothesize that traditional rice varieties, through prolonged adaptation to soil P-deficient conditions, have developed enhanced PUE mechanisms, allowing them to better agricultural performance under low soil P availability, while the modern high-yielding varieties could exbibit reduced performance in such conditions, potentially attributable to relaxed P selection pressures for low-P adaptive traits during breeding programs. In a recent commentary published in Nature Plants, Sajjad Raza et al. highlighted the necessity of integrating anticipated future soil conditions into plant breeding programs, emphasizing the profound influence of edaphic factors on the development and effectiveness of crop improvement strategies [21].
This study employed 16 representative rice varieties in southern China spanning distinct breeding eras: heritage landraces (pre-1940), early conventional cultivars (1940–2000), model conventional cultivars (2000–2020) and modern hybrid cultivars (2000–2020). Through comparative analysis under normal and P-limited conditions, this study aims to (1) Characterize temporal changes in P acquisition and allocation patterns during varietal improvement; (2) Test the above-mentioned hypothesis that traditional varieties possess enhanced P utilization traits due to adaptation to low-P soils. Our research findings will provide a strategic basis for developing the next generation of P-efficient rice varieties and establishing sustainable cultivation programs.

2. Materials and Methods

2.1. Experimental Design

In total, 16 representative rice varieties, spanning distinct breeding eras, were collected and used in the large pot experiment. These varieties were categorized into four groups: heritage landraces (pre-1940), early conventional cultivars (1940–2000), modern conventional cultivars (2000–2020), and modern hybrid cultivars (2000–2020). The rice varieties selected for this experiment were all major cultivars from the special historical periods in the southern rice-growing regions of China. Two P fertilizer treatments were designed: low P stress and normal P application. P fertilizer treatment and rice variety treatment both had four repetitions, resulting in a total of 128 pots.

2.2. Experimental Rice Varieties and Growth Conditions

Each rice group comprised four rice varieties. The heritage landraces included Leihuonian, Jiandaoqi, Caohezi, and Hongjiaozao. The early conventional cultivars consisted of Shenglixian, Zhongnong 4, Zhenzhuai, and Guichao 2. The modern conventional cultivars were Nongxiang 42, Huanghuazhan, Meiyangzhan, and Xiangyaxiangzhan, and the modern hybrids included Y Liangyou 900, Jingliangyouzhan, Huazheyou 261, and Taiyou 553. The heritage landraces and early conventional cultivars were obtained from the Hunan provincial crop germplasm resource bank. Given the low vitality of seeds that have been stored in the seed bank for an extended period, these rice varieties were propagated before this pot experiment, and the freshly propagated seeds were used for this study. The seeds of modern conventional and hybrid cultivars were purchased from commercial companies.
The rice pot experiment was conducted from May 2023 to September 2023 at the Longping Rice Park (113.23867 E, 28.417924 N) in Mingyue Village, Lukou Town, Changsha County, Hunan Province. This site features a subtropical monsoon climate, with an average annual temperature of 18.7 °C and an average annual rainfall of 1347.9 mm. Before the pot experiment, all rice seeds from the sixteen cultivars were uniformly soaked for 24 h, then germinated at 37 °C for 24 h, followed by an additional 12 h of germination at 28 °C. Subsequently, the germinated seeds were placed in rice-specific substrates for seedling cultivation. After 30 days of growth, considering that a small number of seedlings from each variety may exhibit relatively weak growth during the seedling cultivation process, the less vigorous seedlings were excluded, and only those with consistent growth, strong vitality, and representative characteristics were selected for transplanting. To more naturally simulate the rice growth environment, the potted plants were relocated to a field setting that closely matched natural rice cultivation conditions, minimizing the impact of high environmental temperatures on the roots.

2.3. Experimental Soil, Fertilization, and Management

The low-P paddy soil was collected, air-dried, and subsequently, crushed artificially. Residual roots and small stones were manually removed, and then the soil was sieved through a 2-mm mesh to ensure homogeneity for the subsequent pot experiment. The physical and chemical properties of the homogeneous soil before the pot experiment were determined as follows: exhibiting total P (TP) content of 0.40 g·kg−1, available P (AP) content of 6.05 mg·kg−1, total nitrogen (TN) content of 1.34 g·kg−1, alkali-hydrolyzable nitrogen (AN) content of 122.5 mg·kg−1, soil organic matter (SOM) content of 29.72 g·kg−1, and a pH value of 5.43.
The experimental pots (31 cm diameter, 22.3 cm height) were filled with 6 kg of homogenized air-dried soil to ensure consistency. The soil was thoroughly mixed with the base fertilizer, moistened, and left to equilibrate overnight before transplanting the rice seedlings. Based on the experimental design, the low P stress treatment (P0) was established without any P input, whereas the normal P application treatment (P50) was maintained at a rate of 50 kg·ha−1. Nitrogen (N) and potassium (K) were applied at standardized rates of 150 kg·ha−1 and 100 kg·ha−1, respectively, with all fertilizer amounts adjusted from field fertilizer application to pot-based experiments. P fertilizer was applied as a basal fertilizer in a single application. N fertilizer was distributed in a ratio of 5:3:2 as basal, tillering, and panicle fertilizer, respectively. K fertilizer was applied in a 1:1 ratio as basal and panicle fertilizer. The fertilization details per pot were as follows: P fertilizer (1.647 g) was applied as basal in P50 treatment. N fertilizer was applied at basal (0.644 g), tillering (0.3867 g), and panicle stages (0.258 g). K fertilizer (0.329 g) was applied at basal and panicle stages. The P fertilizer used was superphosphate, the N fertilizer was urea, and the K fertilizer was potassium chloride.

2.4. Plant and Soil Harvest and Chemical Analysis

At the ripening stage, when spikes reached 80% maturity, plant shoots and roots were harvested separately, and seeds were counted to determine grain yield. Root samples were carefully rinsed with deionized water to remove adhering soil particles. Shoot, root, and grain dry weights were measured after oven-drying at 70 °C for 48 h to determine biomass. For P content analysis, dried plant samples were milled and digested with sulfuric acid at 350 °C. The P content in roots, stems, and grains was measured using a SAN++ continuous flow injection analyzer (SKALAR) [22]. P accumulation and utilization efficiency were calculated using the following formulas:
P accumulation (g·plant−1) = Plant P content × Plant dry weight [23].
Partial factor productivity of P fertilizer (g·kg−1) = Grain yield under P application/Amount of P applied [24].
P uptake efficiency (%) = (Total aboveground P accumulation under P application/Amount of P applied) × 100% [25].
Soil samples were carefully collected from the rice rhizosphere simultaneously with plant harvest to measure chemical parameters. Before analysis, the rhizosphere soils were air-dried to remove root fragments and then thoroughly homogenized. Soil pH was measured in a 1:2.5 (v/v) soil-to-water suspension using a digital pH meter (PHS-3C, Shanghai Lida Instrument Company, China). Soil available nitrogen (AN) was determined using the alkali hydrolysis diffusion method [26]. Soil organic carbon (SOC) was measured using the dichromate oxidation method [27]. Soil available phosphorus (Olsen-P) was assayed using the ammonium molybdate method after extraction with 0.5 M NaHCO3 [28] The soil dissolvable organic carbon (DOC) was determined by the potassium dichromate external heating method [29].

2.5. Statistical Analysis

A two-way ANOVA was conducted to assess the effects of varietal improvement and P fertilizer treatment on rice agronomic traits and P nutrient acquisition in roots, stems, and grains. The normality of variance for the dependent variables was tested prior to analysis. Except for aboveground biomass, grain P accumulation, and total P accumulation in rice, all data met the assumptions of normality (Shapiro–Wilk test, p > 0.05) and homogeneity of variances (Levene’s test, p > 0.05). If ANOVA detected a significant interaction between varietal replacement and P fertilizer treatment, significance was determined using Duncan’s test at p < 0.05. In the absence of significant interactions, Student’s t-test was used to examine the independent effects of varietal replacement and P fertilizer treatment. For the three variables that did not satisfy the homogeneity of variance assumption, Dunnett’s T3 post hoc test was applied following two-way ANOVA. To further analyze contributing factors to grain yield, a random forest model was constructed using the “randomForest” package [30] in R (version 4.4.1), with the percentage increase in mean squared error (% IncMSE) calculated to identify key variables. The “corrplot” package was used to generate a heatmap illustrating correlations between rice agronomic traits, rhizosphere soil physicochemical properties, and P uptake and utilization under two P fertilizer treatments. Adonis analysis, implemented using the “vegan” package [31], was conducted to assess dissimilarities among rice types based on agronomic traits and rhizosphere soil properties. Additionally, principal component analysis (PCA) was performed, and the results were visualized using Origin 2024. GraphPad Prism (version 8.0) was used to visualize P allocation ratios in roots, stems, and grains, as well as P fertilizer partial productivity and P uptake efficiency.

3. Results

3.1. Changes in Agronomic Traits During Historical Rice Variety Replacement

Over successive breeding periods, key agronomic traits of rice, including grain weight, aboveground biomass, root biomass, root length, and root-to-shoot ratio, have shown a significantly increasing trend (p < 0.001). In contrast, plant height in both model conventional and hybrid rice varieties was significantly lower than in early conventional varieties and heritage landraces. Notably, low P treatment had no significant effect on agronomic traits across the four rice variety types (Figure 1; Table 1).

3.2. Variations in Plant P Uptake During the Historical Rice Variety Replacement

A significant increase in P content was observed in the stems and grains, whereas root P content remained stable along the conventional rice breeding process, rising from 0.26 to 0.69 g·kg−1 and from 1.29 to 1.94 g·kg−1, respectively (Figure 2b,c). Compared to modern conventional rice, contemporaneous hybrid rice varieties exhibited a declining trend in P content across roots, stems, and grains (Figure 2a–c). Compared to normal P treatment, hybrid rice exhibited the strongest response, with significant reductions under low P treatment in P content observed in roots (0.25 vs. 0.27 g·kg−1), stems (0.39 vs. 0.56 g·kg−1), and grains (1.55 vs. 1.83 g·kg−1). In early and modern conventional rice varieties, low P treatment significantly reduced stem P content (p < 0.01; p < 0.001) but had no effect on root or grain P content. In heritage landraces, only grain P content decreased (p < 0.01), while root and stem P levels remained unchanged.

3.3. Characteristics of Rice P Distribution, Accumulation, and Utilization During the Historical Variety Replacement

Total and grain P accumulation in rice from the varieties increased over successive breeding eras from 53.81 to 144.12 g·kg−1 and from 38.90 to 110.04 g·kg−1, respectively (both p < 0.001), while root and stem P accumulation stabilized after an initial rise in early conventional rice (Figure 3a,d). Low P treatment significantly reduced total P accumulation in ancient, modern conventional, and hybrid rice (p < 0.01, p < 0.05, p < 0.001, respectively) but had no effect on early conventional varieties. Low P treatment did not significantly impact root P accumulation across different type of rice varieties (Figure 3b). The negative effect of low P stress on grain P accumulation was strongest in ancient and modern hybrid rice, with no significant impact on other varieties, and the significant interaction was observed between variety type and P treatment (Table 1).
Hybrid rice exhibits higher grain P allocation than other rice varieties (Figure 4a). Under low-P conditions, all rice types exhibit increased P allocation in the roots. However, early and modern conventional rice varieties show a reduction in P allocation in the stems, whereas this effect is less pronounced in ancient and hybrid rice varieties. Additionally, low-P treatment enhances P distribution in grains, except for heritage landraces (Figure 4a). Throughout breeding, partial productivity and P uptake efficiency have significantly improved, with hybrid rice outperforming conventional varieties from the same period (Figure 4b,c).

3.4. Dissimilarity Analysis Across Historical Rice Varieties Under Two P Treatments

Principal component analysis (PCA) of agronomic traits, P uptake, and rhizosphere soil chemical properties was conducted to assess differences among rice varieties. Under low-P conditions, significant differences were observed among the four rice types, except between ancient varieties and early conventional rice, as well as between model conventional rice and hybrid rice (Figure 5a,c). Similarly, under normal P application, significant differences were found among rice types, except between model conventional rice and hybrid rice (Figure 5b,d).

3.5. Correlation of Agronomic Traits, P Utilization, and Yield Drivers Under Two P Treatments

Under both low and normal P application, the root-to-shoot ratio, root biomass, root length, and grain weight exhibited positive correlations with stem P content and P accumulation in roots and stems, while showing negative correlations with rhizosphere soil pH (Figure 6a,b). The low-P treatment enhanced the negative correlation between root P content and grain yield (Figure 6a). The primary determinant of yield was root P content under low-P conditions, accounting for 77% of the variation (Figure 6c), whereas rhizosphere soil pH was the primary driver under normal P conditions, explaining 72% of the variation (Figure 6d).

4. Discussion

4.1. Effects of P Limitation on Rice Yield and Agronomic Traits During Historical Varietal Replacement

The adoption of the semi-dwarf gene sd1 dominated rice varietal improvement in the last century, driving a yield-focused dwarf breeding process [16]. Since the 21st century, breeding objectives have expanded to include stable yield, multi-resistance, and high quality, alongside dwarf traits [32]. Although nutrient uptake is crucial for crop performance, past breeding efforts aimed at improving N use efficiency have not adequately prioritized P use efficiency [33,34,35]. In this study, low P treatment had minimal impact on the yield of various rice varieties, likely due to the available P of soil background. The soil available P content in this study was 6.05 mg·kg−1, typical of low-P paddy soils, but not severely deficient. Previous studies have shown that rice plants exhibit P deficiency phenotypes when soil available P falls below 8 mg·kg−1 [36]. However, no significant differences were observed in major agronomic traits, including biomass and root length, among the four rice types in this study. This may be related to the experimental setup, where each plant was grown in 6 kg of soil, providing a larger soil volume per plant than typical field conditions. Interestingly, most rice varieties showed increased root biomass under low-P conditions, aligning with studies showing that low-P stress enhances root growth to improve nutrient absorption [37]. Given the observed trends in root biomass and P uptake, the low-P treatment did impose physiological stress, making the soil conditions representative of low-P paddy fields in southern China. Notably, no significant differences were observed in low-P tolerance among rice varieties from different breeding eras. Modern high-yield and high-biomass varieties theoretically have higher P demands, and P limitation should have a greater impact on these varieties compared to older ones. However, this was not observed, likely because the historical breeding process has significantly shaped root traits, leading to modern varieties with larger root systems that enhance P absorption, mitigating P stress despite increased biomass demands [38]. Due to genotypic differences, various rice varieties may exhibit differential requirements for N and K fertilization, which could further influence P uptake and utilization efficiency. To ensure the reliability of the experimental results, this study applied N (150 kg ha−1) and K (100 kg ha−1) fertilizers at rates of high agronomic recommendations. This approach was intended to meet the nutritional thresholds of all tested varieties for N and K, thereby effectively eliminating potential interference from N and K supply levels on the effects of P treatments.

4.2. Effects of Soil P Limitation on Plant P Dynamics During Historical Varietal Replacement

Soil P limitation significantly reduced P content in roots, stems, and grains of hybrid rice, likely due to its greater sink capacity and higher P demand during yield formation [39]. In contrast, the impact on other rice types was relatively smaller, primarily reducing grain P concentration in heritage landraces and stem P concentration in early and model conventional rice. Notably, under low-P stress, stem P content and allocation ratio decreased significantly across most varieties, suggesting that plants prioritize internal P transport and redistribution to sustain grain development [40]. In addition to the increased absorption area of rice roots, internal P transport and redistribution are also key mechanisms for plant adaptation to low-P stress [41]. Plants prioritize P transport through the xylem and phloem to actively growing tissues or reproductive organs, ensuring grain development and function through preferential allocation [42]. This study consistently observed an increasing trend in grain P accumulation and allocation ratio under low-P conditions. However, it should be noted that genotype plays a critical role in P absorption and distribution, particularly under low-P conditions. A variety of genes are involved in P uptake and allocation [43]. For instance, OsPT6 and OsPT8 function as high-affinity P transporters responsible for P uptake and subsequent translocation within the plant [44]. SPDT was reported to regulate P allocation in rice, and loss-of-function mutations in SPDT can reduce P accumulation in grains while increasing it in leaves [45]. Although this study has not yet characterized allelic variations of these genes across cultivars, genetic differences are likely key contributors to the observed varietal differences in phosphorus uptake efficiency.
In this study, heritage landrace varieties exhibited lower P fertilizer productivity and P uptake efficiency. These results are inconsistent with our original hypothesis. The possible reason could be their biological characteristics, including lower yield potential and weaker root systems such as lower biomass and shorter roots [46]. These factors limit P uptake duration and reduce P demand, leading to lower P-use efficiency. In contrast, modern hybrid rice varieties, bred for high yield, have optimized plant architecture, characterized by enhanced root development and improved nutrient uptake efficiency [47]. The results indicate that hybrid rice has stronger root growth capacity and greater root biomass, which expands the P absorption area and enhances uptake. Additionally, rice with larger root systems can secrete more root exudates, such as organic acids and phosphatases, which mobilize and activate insoluble soil P, improving P availability [48,49]. Therefore, the higher P uptake for the hybrid rice varieties could not be primarily governed by genotype, but rather attributed to the higher vigor of hybrid rice, which increases the input of carbon sources into the soil, thereby enhancing P activation through soil physicochemical processes and microbial activity.

4.3. Effects of P Application on the Relationship Between Rice Yield, P-Use Efficiency, and Soil Properties During Varietal Replacement

Under low P conditions, the negative correlation between root P content and rice yield was stronger than under normal P conditions. Theoretically, root P content should positively correlate with rice yield. This discrepancy may be due to P metabolism adjustments under low P stress, where roots secrete organic acids and increase surface area to enhance P uptake [50]. Maintaining higher root P concentration for stronger metabolism may result in a negative correlation between root P content and grain yield. Notably, root P accumulation was positively correlated with rice yield in both treatments. Root P accumulation refers to the total P absorbed from the soil [51], encompassing P absorbed and stored by roots. Although root P content under low P conditions may not directly reflect plant growth status, the ability of roots to absorb more P and efficiently transport it to grains favors yield improvement [52]. Interestingly, stem P content and accumulation showed no significant correlation with rice yield under either P treatment, indicating that stems, which serve structural and support functions, do not directly participate in reproductive growth (e.g., grain formation) and have relatively lower P demands. However, under the low-P stress condition, both the ratios of grain P concentration to root P concentration (GPC/RPC) and stem P concentration to root P concentration (SPC/RPC) were identified as key factors affecting rice yield, indicating that the translocation efficiency of P from roots to shoots plays a decisive role in yield formation.
P application increases root biomass, promoting root development and distribution, as roots are the foundation of crop production [53,54]. In this study, root biomass was a significant contributor to rice yield under normal P treatment. Studies have shown that P is involved in plant cell division and root differentiation, promoting root tip growth and enabling roots to penetrate deeper into the soil, expanding contact area and enhancing water and nutrient uptake [55]. It should be noted that the most of tested cultivars demonstrated adaptive phenotypic responses to low-P stress, and the intensity of these responses should be varied with the genotypes. Since this study did not investigate P-related expression during varietal replacement, we are unable to fully disentangle the relative contributions of genetic variation and adaptive plasticity. Nevertheless, we considered that both mechanisms are likely to interact, shaping the observed varietal differences in P acquisition.

5. Conclusions

Our study found that all four rice types exhibited a consistent increasing trend in root-to-shoot ratio, root length, and belowground biomass, with negligible impact on yield under soil P limitation. These findings suggest the presence of adaptive phenotypic responses for all rice varieties to low-P stress. The low-P treatment significantly reduced P content in the roots, stems, and grains of hybrid rice, while only affecting stem P content in early and model conventional rice and grain P content in heritage landraces. These differential patterns are likely driven by both genotype-specific and physiological strategies. Distinct P allocation patterns were observed among rice types: heritage landraces and early conventional rice tended to accumulate more P in roots, whereas model conventional and hybrid rice allocated more P to grains. Additionally, rice varieties from different eras exhibited differences in P uptake and utilization efficiency, with model conventional and hybrid rice demonstrating higher efficiency in both aspects. Collectively, these results highlight the influence of historical breeding efforts on P utilization strategies in rice. Future research should focus on optimizing root traits and internal P redistribution mechanisms to enhance P use efficiency and ensure sustainable rice production under low-P conditions.

Author Contributions

Y.H. conceived and supervised the work; C.L. and X.M. conducted the experiments, analyzed the data, and prepared the figures; S.L., Y.L., R.C., S.Y., W.L. and Y.W. assisted in the parameter measurement and data analysis; C.L. drafted the manuscript, together with Y.H., X.M., S.L., Y.L., R.C. and S.Y. All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by the National Science Foundation of China (Grant No. 42277309) in 2023.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author(s).

Acknowledgments

The authors thank C.W., H.Y., S.Y. and Y.Z. of Hunan Agricultural University for all their help during the experiments.

Conflicts of Interest

The authors declare no conflict of interest.

Abbreviations

The following abbreviations are used in this manuscript:
GYGrain weight
HPlant height
RLRoot length
BGBRoot biomass
AGBAboveground biomass
GGBRoot-to-shoot ratio
RPCRoot P content
SPCStem P content
GPCGrain P content
RPARoot P accumulation
SPAStem P accumulation
GPAGrain P accumulation
PTPATotal P accumulation
ANAlkali-hydrolyzable nitrogen
DOCDissolved organic carbon
APSoil available P

References

  1. Jahan, N.; Mahmud, U.; Khan, M.Z. Sustainable Plant-Soil Phosphorus Management in Agricultural Systems: Challenges, Environmental Impacts and Innovative Solutions. Discov. Soil. 2025, 2, 13. [Google Scholar] [CrossRef]
  2. Veneklaas, E.J.; Lambers, H.; Bragg, J.; Finnegan, P.M.; Lovelock, C.E.; Plaxton, W.C.; Price, C.A.; Scheible, W.-R.; Shane, M.W.; White, P.J.; et al. Opportunities for Improving Phosphorus-Use Efficiency in Crop Plants. New Phytol. 2012, 195, 306–320. [Google Scholar] [CrossRef] [PubMed]
  3. Kale, R.R.; Anila, M.; Mahadeva Swamy, H.K.; Bhadana, V.P.; Durga Rani, C.V.; Senguttuvel, P.; Subrahmanyam, D.; Hajira, S.K.; Rekha, G.; Ayyappadass, M.; et al. Morphological and Molecular Screening of Rice Germplasm Lines for Low Soil P Tolerance. J. Plant Biochem. Biotechnol. 2021, 30, 275–286. [Google Scholar] [CrossRef]
  4. Pazhamala, L.T.; Giri, J. Plant Phosphate Status Influences Root Biotic Interactions. J. Exp. Bot. 2023, 74, 2829–2844. [Google Scholar] [CrossRef] [PubMed]
  5. Sun, R.; Zhang, W.; Liu, Y.; Yun, W.; Luo, B.; Chai, R.; Zhang, C.; Xiang, X.; Su, X. Changes in Phosphorus Mobilization and Community Assembly of Bacterial and Fungal Communities in Rice Rhizosphere under Phosphate Deficiency. Front. Microbiol. 2022, 13, 953340. [Google Scholar] [CrossRef]
  6. An, R.; Yu, R.-P.; Xing, Y.; Zhang, J.-D.; Bao, X.-G.; Lambers, H.; Li, L. Enhanced Phosphorus-Fertilizer-Use Efficiency and Sustainable Phosphorus Management with Intercropping. Agron. Sustain. Dev. 2023, 43, 57. [Google Scholar] [CrossRef]
  7. Zhao, L.; Zhao, X.; Huang, L.; Liu, X.; Wang, P. Transcriptome Analysis of Pennisetum Americanum × Pennisetum Purpureum and Pennisetum Americanum Leaves in Response to High-Phosphorus Stress. BMC Plant Biol. 2024, 24, 635. [Google Scholar] [CrossRef]
  8. Chowdhury, R.B.; Moore, G.A.; Weatherley, A.J.; Arora, M. Key Sustainability Challenges for the Global Phosphorus Resource, Their Implications for Global Food Security, and Options for Mitigation. J. Clean. Prod. 2017, 140, 945–963. [Google Scholar] [CrossRef]
  9. Gilbert, N. Environment: The Disappearing Nutrient. Nature 2009, 461, 716–718. [Google Scholar] [CrossRef]
  10. Soumya, P.R.; Vengavasi, K.; Pandey, R. Adaptive Strategies of Plants to Conserve Internal Phosphorus under P Deficient Condition to Improve P Utilization Efficiency. Physiol. Mol. Biol. Plants 2022, 28, 1981–1993. [Google Scholar] [CrossRef]
  11. Srivastava, A.; Gupta, A.; Bishi, S.K.; Akhila, P.; Latha, P.C.; Subrahmanyam, D.; Brajendra, P.; Anantha, M.S.; Ch, S.R.; Sakhare, A.S.; et al. Tolerance of Oryza sativa to Low Phosphate Is Associated with Adaptive Changes in Root Architecture and Metabolic Exudates. Plant Sci. 2025, 353, 112415. [Google Scholar] [CrossRef]
  12. Smith, S.E.; Anderson, I.C.; Smith, F.A. Mycorrhizal Associations and Phosphorus Acquisition: From Cells to Ecosystems. In Annual Plant Reviews Volume 48; John Wiley & Sons, Ltd.: Hoboken, NJ, USA, 2015; pp. 409–439. ISBN 978-1-118-95884-1. [Google Scholar]
  13. Dissanayaka, D.M.S.B.; Plaxton, W.C.; Lambers, H.; Siebers, M.; Marambe, B.; Wasaki, J. Molecular Mechanisms Underpinning Phosphorus-Use Efficiency in Rice. Plant Cell Environ. 2018, 41, 1483–1496. [Google Scholar] [CrossRef]
  14. Lin, H.; Li, T.; Tong, H.; Wang, Z.; Wang, L.; E, Z. Analysis on Evolution of Major Rice Cultivars in China. Chin. J. Rice Sci. 2018, 32, 565–571. [Google Scholar] [CrossRef]
  15. Wu, B.; Hu, W.; Xing, Y.Z. The History and Prospect of Rice Genetic Breeding in China. Hereditas 2018, 40, 841–857. [Google Scholar] [CrossRef] [PubMed]
  16. Yu, Y.; Hu, X.; Zhu, Y.; Mao, D. Re-Evaluation of the Rice ‘Green Revolution’ Gene: The Weak Allele SD1-EQ from Japonica Rice May Be Beneficial for Super Indica Rice Breeding in the Post-Green Revolution Era. Mol. Breed. 2020, 40, 84. [Google Scholar] [CrossRef]
  17. Huang, F. Responses of Grain Yield and Phosphorus Efficiency of Wheat Cultivars Released in Different Decades to Soil Fertility Levels in Guanzhong Plain, Shaanxi. Master’s Thesis, Northwest A&F University, Xianyang, China, 2016. [Google Scholar]
  18. Zhang, W.; Chen, X.; Ma, L.; Deng, Y.; Cao, N.; Xiao, R.; Zhang, F.; Chen, X. Re-prediction of Phosphate Fertilizer Demand in China Based on Agriculture Green Development. Acta Pedol. Sin. 2023, 60, 1389–1397. [Google Scholar]
  19. Qian, Q.; Guo, L.; Smith, S.M.; Li, J. Breeding High-Yield Superior Quality Hybrid Super Rice by Rational Design. Natl. Sci. Rev. 2016, 3, 283–294. [Google Scholar] [CrossRef]
  20. Gómez-Gallego, T.; Sánchez-Castro, I.; Molina, L.; Trasar-Cepeda, C.; García-Izquierdo, C.; Ramos, J.L.; Segura, A. Phosphorus Acquisition by Plants: Challenges and Promising Strategies for Sustainable Agriculture in the 21st Century. Pedosphere 2025, 35, 193–215. [Google Scholar] [CrossRef]
  21. Raza, S.; Pandey, B.K.; Hawkesford, M.J.; Griffiths, S.; Bennett, M.J.; Mooney, S.J. Future Crop Breeding Needs to Consider Future Soils. Nat. Plants 2025. [Google Scholar] [CrossRef]
  22. Xu, J.; Lü, T.; Mao, C. Determination of Inorganic Phosphate in Rice by SKALAR San++ Continuous Flowing Analyzer. Anal. Instrum. 2018, 46–50. [Google Scholar]
  23. Tian, Z.; Li, J.; He, X.; Jia, X.; Yang, F.; Wang, Z. Grain Yield, Dry Weight and Phosphorus Accumulation and Translocation in Two Rice (Oryza Sativa L.) Varieties as Affected by Salt-Alkali and Phosphorus. Sustainability 2017, 9, 1461. [Google Scholar] [CrossRef]
  24. Du, J.; Han, T.; Qu, X.; Ma, C.; Liu, K.; Huang, J.; Sheng, Z.; Zhang, L.; Liu, L.; Xie, J.; et al. Spatial-Temporal Evolution Characteristics and Driving Factors of Partial Phosphorus Productivity in Major Grain Crops in China. J. Plant Nutr. Fertil. 2022, 28, 191–204. [Google Scholar]
  25. Yan, J. Effect of Phosphorus Fertilizer Rate on Crop Yield, Phosphorus Utilization and Soil Phosphorus Transformation in a Rice-Oilseed Rape Rotation. Ph.D. Dissertation, Huazhong Agricultural University, Wuhan, China, 2022. [Google Scholar]
  26. Lu, R.K. Analysis Methods of Soil Agricultural Chemistry; China Agricultural Science Press: Beijing, China, 2020. [Google Scholar]
  27. Sparks, D.L.; Page, A.L.; Helmke, P.A.; Loeppert, R.H.; Soltanpour, P.N.; Tabatabai, M.A.; Johnston, C.T.; Sumner, M.E. Methods of Soil Analysis. Part 3: Chemical Methods; Soil Science Society of America: Madison, WI, USA, 1996. [Google Scholar]
  28. Olsen, S.R.; Cole, C.V.; Watanabe, F.S.; Dean, L.A. Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate; US Department of Agriculture: Washington, DC, USA, 1954. [Google Scholar]
  29. Shuang, L.; Ni, S.; Du, J.; Teng, Z.; Shi, C. Determination of Organic Carbon in Geochemical Soil Sample by Potassium Dichromate Oxidation-Heating Method. Anhui Chem. Ind. 2016, 42, 110–112. [Google Scholar]
  30. Aiyelokun, O.O.; Agbede, O.A. Development of Random Forest Model as Decision Support Tool in Water Resources Management of Ogun Headwater Catchments. Appl. Water Sci. 2021, 11, 130. [Google Scholar] [CrossRef]
  31. Dixon, P. VEGAN, a Package of R Functions for Community Ecology. J. Veg. Sci. 2003, 14, 927–930. [Google Scholar] [CrossRef]
  32. Tang, S.; Wang, X.; Liu, X. Study on the Renewed Tendency and Key Backbone-Parents of Inbred Rice Varieties (O. sativa L.) in China. Sci. Agric. Sin. 2012, 45, 1455–1464. [Google Scholar]
  33. Lammerts van Bueren, E.T.; Struik, P.C. Diverse Concepts of Breeding for Nitrogen Use Efficiency. A Review. Agron. Sustain. Dev. 2017, 37, 50. [Google Scholar] [CrossRef]
  34. Ali, J.; Jewel, Z.A.; Mahender, A.; Anandan, A.; Hernandez, J.; Li, Z. Molecular Genetics and Breeding for Nutrient Use Efficiency in Rice. Int. J. Mol. Sci. 2018, 19, 1762. [Google Scholar] [CrossRef]
  35. Vinod, K.K.; Heuer, S. Approaches towards Nitrogen- and Phosphorus-Efficient Rice. AoB Plants 2012, 2012, pls028. [Google Scholar] [CrossRef]
  36. Liu, Y.; Li, Z.; Mi, G.; Zhang, H.; Mu, P.; Wang, X. Screening and Identification for Tolerance to Low-phosphorus Stress of Rice Germplasm (Oryza sativa L.). Acta Agron. Sin. 2005, 31, 238–242. [Google Scholar]
  37. Rajamanickam, V.; Vinod, K.K.; Vengavasi, K.; Kumar, T.; Chinnusamy, V.; Pandey, R. Root Architectural Adaptations to Phosphorus Deficiency: Unraveling Genotypic Variability in Wheat Seedlings. Agriculture 2024, 14, 447. [Google Scholar] [CrossRef]
  38. Verbeeck, M.; Houben, E.; De Bauw, P.; Rakotoson, T.; Merckx, R.; Smolders, E. Root Biomass Explains Genotypic Differences in Phosphorus Uptake of Rainfed Rice Subjected to Water and Phosphorus Stresses. Plant Soil. 2023, 486, 253–271. [Google Scholar] [CrossRef]
  39. Yuan, K. Agronomic Performance, Energy Efficiency, and Economic Analysis of Inbred and Hybrid Rice Grown Under Reduced-Input Crop Management Practices. Ph.D. Thesis, Huazhong Agricultural University, Wuhan, China, 2020. [Google Scholar] [CrossRef]
  40. Julia, C.; Wissuwa, M.; Kretzschmar, T.; Jeong, K.; Rose, T. Phosphorus Uptake, Partitioning and Redistribution during Grain Filling in Rice. Ann. Bot. 2016, 118, 1151–1162. [Google Scholar] [CrossRef]
  41. Baker, A.; Ceasar, S.A.; Palmer, A.J.; Paterson, J.B.; Qi, W.; Muench, S.P.; Baldwin, S.A. Replace, Reuse, Recycle: Improving the Sustainable Use of Phosphorus by Plants. J. Exp. Bot. 2015, 66, 3523–3540. [Google Scholar] [CrossRef]
  42. El Mazlouzi, M.; Morel, C.; Chesseron, C.; Robert, T.; Mollier, A. Contribution of External and Internal Phosphorus Sources to Grain P Loading in Durum Wheat (Triticum durum L.) Grown Under Contrasting P Levels. Front. Plant Sci. 2020, 11, 870. [Google Scholar] [CrossRef] [PubMed]
  43. Yang, S.-Y.; Lin, W.-Y.; Hsiao, Y.-M.; Chiou, T.-J. Milestones in Understanding Transport, Sensing, and Signaling of the Plant Nutrient Phosphorus. Plant Cell 2024, 36, 1504–1523. [Google Scholar] [CrossRef]
  44. Jia, H.; Ren, H.; Gu, M.; Zhao, J.; Sun, S.; Zhang, X.; Chen, J.; Wu, P.; Xu, G. The Phosphate Transporter Gene OsPht1;8 Is Involved in Phosphate Homeostasis in Rice. Plant Physiol. 2011, 156, 1164–1175. [Google Scholar] [CrossRef]
  45. Yamaji, N.; Takemoto, Y.; Miyaji, T.; Mitani-Ueno, N.; Yoshida, K.T.; Ma, J.F. Reducing Phosphorus Accumulation in Rice Grains with an Impaired Transporter in the Node. Nature 2016, 541, 92–95. [Google Scholar] [CrossRef]
  46. Wang, D. The Change of Plant Type and Nitrogen Use Efficiency during Rice Cultivar Improvement. Ph.D. Thesis, Chinese Academy of Agricultural Sciences, Beijing, China, 2008. [Google Scholar]
  47. Fu, Y.; Lu, C.; Zhong, X.; Liang, K.; Pan, J.; Liu, Y.; Hu, X.; Hu, R.; Li, M.-J.; Wang, X.; et al. Post-Heading Dry-Matter Transport and Nutrient Uptake Differentiate Hybrid and Inbred Indica Rice in the Double-Cropping System in South China. Front. Plant Sci. 2024, 15, 1433402. [Google Scholar] [CrossRef]
  48. Pantigoso, H.A.; Manter, D.K.; Fonte, S.J.; Vivanco, J.M. Root Exudate-Derived Compounds Stimulate the Phosphorus Solubilizing Ability of Bacteria. Sci. Rep. 2023, 13, 4050. [Google Scholar] [CrossRef]
  49. Matsushima, C.; Shenton, M.; Kitahara, A.; Wasaki, J.; Oikawa, A.; Cheng, W.; Ikeo, K.; Tawaraya, K. Multiple Analysis of Root Exudates and Microbiome in Rice (Oryza sativa) under Low P Conditions. Arch. Microbiol. 2021, 203, 5599–5611. [Google Scholar] [CrossRef] [PubMed]
  50. Wang, J.; Zhang, L.; Wang, L.; Zhu, Y.; Shao, G.; Cui, C. Effects of Different Phosphorus Levels on Root Growth of Rice Cultivars and the Absorption of Some Nutrient Elements. J. Southwest Univ. (Nat. Sci. Ed.) 2015, 37, 30–36. [Google Scholar] [CrossRef]
  51. Liu, X. Screening of Nitrogen- and Phosphorus-Efficient Rice Varieties and Their Morpho-Physiological Characteristics. Master’s Thesis, Yangzhou University, Yangzhou, China, 2024. [Google Scholar]
  52. Liu, K.; Li, T.; Chen, Y.; Huang, J.; Qiu, Y.; Li, S.; Wang, H.; Zhu, A.; Zhuo, X.; Yu, F.; et al. Effects of Root Morphology and Physiology on the Formation and Regulation of Large Panicles in Rice. Field Crops Res. 2020, 258, 107946. [Google Scholar] [CrossRef]
  53. Oo, A.Z.; Tsujimoto, Y.; Mukai, M.; Nishigaki, T.; Takai, T.; Uga, Y. Significant Interaction between Root System Architecture and Stratified Phosphorus Availability for the Initial Growth of Rice in a Flooded Soil Culture. Rhizosphere 2024, 31, 100947. [Google Scholar] [CrossRef]
  54. Gonçalves, B.X.; Lima-Melo, Y.; Maraschin, F.D.S.; Margis-Pinheiro, M. Phosphate Starvation Responses in Crop Roots: From Well-Known Players to Novel Candidates. Environ. Exp. Bot. 2020, 178, 104162. [Google Scholar] [CrossRef]
  55. Lou, Y.; Yang, W.; Yang, L.; Li, T.; Lu, J.; Lou, Q. Comparison of Roots Plasticity in Two Rice Groups with Adverse Root Architectures. J. Nucl. Agric. Sci. 2018, 32, 1220–1229. [Google Scholar]
Agronomy 15 00983 g001
Figure 1. Agronomic traits of four rive type across breeding eras. (a) Grain weight; (b) Plant height; (c) Root length; (d) Root biomass; (e) Aboveground biomass; (f) Root-shoot ratio; <1940 refers to ancient rice (<1940), 1940–2000 refers to early conventional rice (1940–2000), 2000–2020C refers to modern conventional rice (2000–2020), and 2000–2020Z refers to hybrid rice (2000–2020), P0 represents low P stress treatment, and P50 represents normal P application treatment. Different lowercase letters indicate statistically significant differences among the four rice types within each P treatment.
Figure 1. Agronomic traits of four rive type across breeding eras. (a) Grain weight; (b) Plant height; (c) Root length; (d) Root biomass; (e) Aboveground biomass; (f) Root-shoot ratio; <1940 refers to ancient rice (<1940), 1940–2000 refers to early conventional rice (1940–2000), 2000–2020C refers to modern conventional rice (2000–2020), and 2000–2020Z refers to hybrid rice (2000–2020), P0 represents low P stress treatment, and P50 represents normal P application treatment. Different lowercase letters indicate statistically significant differences among the four rice types within each P treatment.
Agronomy 15 00983 g001
Agronomy 15 00983 g002
Figure 2. Root P content (a), stem P content (b), and grain P content (c) of four rive type across breeding eras; <1940 refers to ancient rice (<1940), 1940–2000 refers to early conventional rice (1940–2000), 2000–2020C refers to modern conventional rice (2000–2020), and 2000–2020Z refers to hybrid rice (2000–2020). P0 represents low P stress treatment, and P50 represents normal P application treatment. Different lowercase letters indicate statistically significant differences among the four rice types within each P treatments. Asterisk shows a significant difference between P0 and P50 treatment. “*” indicates significant difference at the p < 0.05 level, “**” indicates significant difference at the p < 0.01 level, and “***” indicates significant difference at the p < 0.001 level.
Figure 2. Root P content (a), stem P content (b), and grain P content (c) of four rive type across breeding eras; <1940 refers to ancient rice (<1940), 1940–2000 refers to early conventional rice (1940–2000), 2000–2020C refers to modern conventional rice (2000–2020), and 2000–2020Z refers to hybrid rice (2000–2020). P0 represents low P stress treatment, and P50 represents normal P application treatment. Different lowercase letters indicate statistically significant differences among the four rice types within each P treatments. Asterisk shows a significant difference between P0 and P50 treatment. “*” indicates significant difference at the p < 0.05 level, “**” indicates significant difference at the p < 0.01 level, and “***” indicates significant difference at the p < 0.001 level.
Agronomy 15 00983 g002
Agronomy 15 00983 g003
Figure 3. The total P accumulation and distribution of four rive type across breeding eras. (a) Total P accumulation; (b) Root P accumulation; (c) Stem P accumulation; (d) Grain P accumulation. <1940 refers to ancient rice (<1940), 1940–2000 refers to early conventional rice (1940–2000), 2000–2020C refers to modern conventional rice (2000–2020), and 2000–2020Z refers to hybrid rice (2000–2020). P0 represents low P stress treatment, and P50 represents normal P application treatment. Different lowercase letters indicate statistically significant differences among the four rice types within each P treatments in (a–c). Different lowercase letters indicate statistically significant differences for all treatments due to the significant interaction between varietal replacement and P fertilizer treatment was observed in (d). Asterisk shows a significant difference between P0 and P50 treatment. “*” indicates significant difference at the p < 0.05 level, “**” indicates significant difference at the p < 0.01 level.
Figure 3. The total P accumulation and distribution of four rive type across breeding eras. (a) Total P accumulation; (b) Root P accumulation; (c) Stem P accumulation; (d) Grain P accumulation. <1940 refers to ancient rice (<1940), 1940–2000 refers to early conventional rice (1940–2000), 2000–2020C refers to modern conventional rice (2000–2020), and 2000–2020Z refers to hybrid rice (2000–2020). P0 represents low P stress treatment, and P50 represents normal P application treatment. Different lowercase letters indicate statistically significant differences among the four rice types within each P treatments in (a–c). Different lowercase letters indicate statistically significant differences for all treatments due to the significant interaction between varietal replacement and P fertilizer treatment was observed in (d). Asterisk shows a significant difference between P0 and P50 treatment. “*” indicates significant difference at the p < 0.05 level, “**” indicates significant difference at the p < 0.01 level.
Agronomy 15 00983 g003
Agronomy 15 00983 g004
Figure 4. (a) represents the proportion of P accumulation in rice roots, stems, and grains of four rive type across breeding eras; (b) shows the partial factor productivity of P fertilizer of four rive type across breeding eras; (c) represents the P uptake efficiency of four rive type across breeding eras. <1940 refers to ancient rice (<1940), 1940–2000 refers to early conventional rice (1940–2000), 2000–2020C refers to modern conventional rice (2000–2020), and 2000–2020Z refers to hybrid rice (2000–2020). P0 represents low P stress treatment, and P50 represents normal P application treatment. Different lowercase letters indicate statistically significant differences among the four rice types.
Figure 4. (a) represents the proportion of P accumulation in rice roots, stems, and grains of four rive type across breeding eras; (b) shows the partial factor productivity of P fertilizer of four rive type across breeding eras; (c) represents the P uptake efficiency of four rive type across breeding eras. <1940 refers to ancient rice (<1940), 1940–2000 refers to early conventional rice (1940–2000), 2000–2020C refers to modern conventional rice (2000–2020), and 2000–2020Z refers to hybrid rice (2000–2020). P0 represents low P stress treatment, and P50 represents normal P application treatment. Different lowercase letters indicate statistically significant differences among the four rice types.
Agronomy 15 00983 g004
Agronomy 15 00983 g005
Figure 5. Principal component analysis of agronomic traits, P uptake, and rhizosphere chemical properties for four types of rice under two P application treatments. (a,b) represent the plots of principal component analysis under low P and normal P application treatment, respectively; (c,d) represent the statistical differences among four rice types under low P and normal P application, respectively. Red color in (c,d) figure indicate significance at the 0.01 level, while dark brown color represent significance at the 0.05 level. GY: Grain weight, H: Plant height, RL: Root length, BGB: Root biomass, AGB: Aboveground biomass, GGB: Root-to-shoot ratio, RPC: Root P content, SPC: Stem P content, GPC: Grain P content, RPA: Root P accumulation, SPA: Stem P accumulation, AN: alkali-hydrolyzable nitrogen, DOC: dissolved organic carbon, and AP: available P.
Figure 5. Principal component analysis of agronomic traits, P uptake, and rhizosphere chemical properties for four types of rice under two P application treatments. (a,b) represent the plots of principal component analysis under low P and normal P application treatment, respectively; (c,d) represent the statistical differences among four rice types under low P and normal P application, respectively. Red color in (c,d) figure indicate significance at the 0.01 level, while dark brown color represent significance at the 0.05 level. GY: Grain weight, H: Plant height, RL: Root length, BGB: Root biomass, AGB: Aboveground biomass, GGB: Root-to-shoot ratio, RPC: Root P content, SPC: Stem P content, GPC: Grain P content, RPA: Root P accumulation, SPA: Stem P accumulation, AN: alkali-hydrolyzable nitrogen, DOC: dissolved organic carbon, and AP: available P.
Agronomy 15 00983 g005
Agronomy 15 00983 g006
Figure 6. Correlation analysis of agronomic traits, rhizosphere chemical parameters, and P uptake in rice under low P treatment (a) and normal P treatment (b); (c,d) show the comprehensive influencing factors of yield based on the random forest model under low P and normal P treatments, respectively. GY: Grain weight, H: Plant height, RL: Root length, BGB: Root biomass, AGB: Aboveground biomass (including grain weight), GGB: Root-to-shoot ratio, RPC: Root P content, SPC: Stem P content, GPC: Grain P content, RPA: Root Paccumulation, SPA: Stem P accumulation, AN: alkali-hydrolyzable nitrogen, DOC: dissolved organic carbon, AP: available P. “ns” indicates no significant difference at p > 0.05, “*” indicates significant difference at p < 0.05, and “**” indicates highly significant difference at p < 0.01.
Figure 6. Correlation analysis of agronomic traits, rhizosphere chemical parameters, and P uptake in rice under low P treatment (a) and normal P treatment (b); (c,d) show the comprehensive influencing factors of yield based on the random forest model under low P and normal P treatments, respectively. GY: Grain weight, H: Plant height, RL: Root length, BGB: Root biomass, AGB: Aboveground biomass (including grain weight), GGB: Root-to-shoot ratio, RPC: Root P content, SPC: Stem P content, GPC: Grain P content, RPA: Root Paccumulation, SPA: Stem P accumulation, AN: alkali-hydrolyzable nitrogen, DOC: dissolved organic carbon, AP: available P. “ns” indicates no significant difference at p > 0.05, “*” indicates significant difference at p < 0.05, and “**” indicates highly significant difference at p < 0.01.
Agronomy 15 00983 g006
Table 1. Two-way ANOVA analysis of agronomic traits and P uptake dynamics during historical rice varietal improvement.
Table 1. Two-way ANOVA analysis of agronomic traits and P uptake dynamics during historical rice varietal improvement.
GYHGLBGBAGBGGBRPCSPCGPCPTPARPASPAGPA
Rice type17833.7945.1664.0538.1126.0623.9235.5220.77102.129.6228.75120.80
***************************************
P treatment0.380.232.670.190.210.554.9035.505.72105.70.3922.5535.14
nsnsnsnsnsns********ns****
Rice type × P treatment 0.310.140.880.061.690.150.981.121.48 2.840.431.514.16
nsnsnsnsnsnsnsnsns*nsns*
GY: Grain weight, H: Plant height, RL: Root length, BGB: Root biomass, AGB: Aboveground biomass (including grain weight), GGB: Root-to-shoot ratio, RPC: Root phosphorus content, SPC: Stem phosphorus content, GPC: Grain phosphorus content, PTPA: Total P accumulation in rice, RPA: Root P accumulation, SPA: Stem P accumulation, GPA: Grain P accumulation. “ns” indicates no significant difference at p > 0.05, “*” indicates significant difference at p < 0.05, and “***” indicates highly significant difference at p < 0.001.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Li, C.; Mo, X.; Li, S.; Liu, Y.; Chen, R.; Yu, S.; Lin, W.; Wang, Y.; Hu, Y. Response of Agronomic Traits and Phosphorus Uptake to Soil P Deficiency During Rice Cultivars Improvement. Agronomy 2025, 15, 983. https://doi.org/10.3390/agronomy15040983

AMA Style

Li C, Mo X, Li S, Liu Y, Chen R, Yu S, Lin W, Wang Y, Hu Y. Response of Agronomic Traits and Phosphorus Uptake to Soil P Deficiency During Rice Cultivars Improvement. Agronomy. 2025; 15(4):983. https://doi.org/10.3390/agronomy15040983

Chicago/Turabian Style

Li, Chunqin, Xu Mo, Shuwei Li, Yuxi Liu, Rongxin Chen, Shuying Yu, Wenqiang Lin, Yifeng Wang, and Yajun Hu. 2025. "Response of Agronomic Traits and Phosphorus Uptake to Soil P Deficiency During Rice Cultivars Improvement" Agronomy 15, no. 4: 983. https://doi.org/10.3390/agronomy15040983

APA Style

Li, C., Mo, X., Li, S., Liu, Y., Chen, R., Yu, S., Lin, W., Wang, Y., & Hu, Y. (2025). Response of Agronomic Traits and Phosphorus Uptake to Soil P Deficiency During Rice Cultivars Improvement. Agronomy, 15(4), 983. https://doi.org/10.3390/agronomy15040983

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop