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Genotypic Variation in Grain P Loading across Diverse Rice Growing Environments and Implications for Field P Balances

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ABSTRACT

More than 60% of phosphorus (P) taken up by rice (Oryza spp.) is accumulated in the grains at harvest and hence exported from fields, leading to a continuous removal of P. If P removed from fields is not replaced by P inputs then soil P stocks decline, with consequences for subsequent crops. Breeding rice genotypes with a low concentration of P in the grains could be a strategy to reduce maintenance fertilizer needs and slow soil P depletion in low input systems. This study aimed to assess variation in grain P concentrations among rice genotypes across diverse environments and evaluate the implications for field P balances at various grain yield levels. Multi-location screening experiments were conducted at different sites across Africa and Asia and yield components and grain P concentrations were determined at harvest. Genotypic variation in grain P concentration was evaluated while considering differences in P supply and grain yield using cluster analysis to group environments and boundary line analysis to determine minimum grain P concentrations at various yield levels. Average grain P concentrations across genotypes varied almost 3-fold among environments, from 1.4 to 3.9 mg g−1. Minimum grain P concentrations associated with grain yields of 150, 300, and 500 g m−2 varied between 1.2 and 1.7, 1.3 and 1.8, and 1.7 and 2.2 mg g−1 among genotypes respectively. Two genotypes, Santhi Sufaid and DJ123, were identified as potential donors for breeding for low grain P concentration. Improvements in P balances that could be achieved by exploiting this genotypic variation are in the range of less than 0.10 g P m−2 (1 kg P ha−1) in low yielding systems, and 0.15–0.50 g P m−2 (1.5–5.0 kg P ha−1) in higher yielding systems. Improved crop management and alternative breeding approaches may be required to achieve larger reductions in grain P concentrations in rice.

No MeSH data available.


Range in grain P concentration among genotypes in each environment with each line representing the minimum and maximum grain P concentration observed in a certain environment. Environments are sorted from lowest (down) to highest (up) mean grain P concentration. The labels next to the lines are environment numbers as presented in Table 1.
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Figure 2: Range in grain P concentration among genotypes in each environment with each line representing the minimum and maximum grain P concentration observed in a certain environment. Environments are sorted from lowest (down) to highest (up) mean grain P concentration. The labels next to the lines are environment numbers as presented in Table 1.

Mentions: Average grain P concentrations across genotypes varied almost 3-fold among environments, from 1.4 to 3.9 mg g−1 (Supplementary Datasheet 1). On average across environments, grain P concentration tended to be higher under lowland conditions than under upland conditions (2.8 vs. 2.4 mg g−1) and higher when P was applied (2.8 vs. 2.3 mg g−1). Within environments, grain P concentration varied 1.3- to 2.7-fold among genotypes (Supplementary Datasheet 1 and Figure 2). The difference between the minimum and maximum observed grain P concentration within one environment was on average 1.2 mg g−1 and ranged between 0.5 and 2.0 mg g−1 (Figure 2). The lowest observed grain P concentration was 1.1 mg g−1 for the genotype Dawebyan in environment 38 and the highest observed grain P concentration was 4.7 mg g−1 for the genotype Kalubala Vee in environment 32 (Supplementary Datasheet 1).


Genotypic Variation in Grain P Loading across Diverse Rice Growing Environments and Implications for Field P Balances
Range in grain P concentration among genotypes in each environment with each line representing the minimum and maximum grain P concentration observed in a certain environment. Environments are sorted from lowest (down) to highest (up) mean grain P concentration. The labels next to the lines are environment numbers as presented in Table 1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037189&req=5

Figure 2: Range in grain P concentration among genotypes in each environment with each line representing the minimum and maximum grain P concentration observed in a certain environment. Environments are sorted from lowest (down) to highest (up) mean grain P concentration. The labels next to the lines are environment numbers as presented in Table 1.
Mentions: Average grain P concentrations across genotypes varied almost 3-fold among environments, from 1.4 to 3.9 mg g−1 (Supplementary Datasheet 1). On average across environments, grain P concentration tended to be higher under lowland conditions than under upland conditions (2.8 vs. 2.4 mg g−1) and higher when P was applied (2.8 vs. 2.3 mg g−1). Within environments, grain P concentration varied 1.3- to 2.7-fold among genotypes (Supplementary Datasheet 1 and Figure 2). The difference between the minimum and maximum observed grain P concentration within one environment was on average 1.2 mg g−1 and ranged between 0.5 and 2.0 mg g−1 (Figure 2). The lowest observed grain P concentration was 1.1 mg g−1 for the genotype Dawebyan in environment 38 and the highest observed grain P concentration was 4.7 mg g−1 for the genotype Kalubala Vee in environment 32 (Supplementary Datasheet 1).

View Article: PubMed Central - PubMed

ABSTRACT

More than 60% of phosphorus (P) taken up by rice (Oryza spp.) is accumulated in the grains at harvest and hence exported from fields, leading to a continuous removal of P. If P removed from fields is not replaced by P inputs then soil P stocks decline, with consequences for subsequent crops. Breeding rice genotypes with a low concentration of P in the grains could be a strategy to reduce maintenance fertilizer needs and slow soil P depletion in low input systems. This study aimed to assess variation in grain P concentrations among rice genotypes across diverse environments and evaluate the implications for field P balances at various grain yield levels. Multi-location screening experiments were conducted at different sites across Africa and Asia and yield components and grain P concentrations were determined at harvest. Genotypic variation in grain P concentration was evaluated while considering differences in P supply and grain yield using cluster analysis to group environments and boundary line analysis to determine minimum grain P concentrations at various yield levels. Average grain P concentrations across genotypes varied almost 3-fold among environments, from 1.4 to 3.9 mg g−1. Minimum grain P concentrations associated with grain yields of 150, 300, and 500 g m−2 varied between 1.2 and 1.7, 1.3 and 1.8, and 1.7 and 2.2 mg g−1 among genotypes respectively. Two genotypes, Santhi Sufaid and DJ123, were identified as potential donors for breeding for low grain P concentration. Improvements in P balances that could be achieved by exploiting this genotypic variation are in the range of less than 0.10 g P m−2 (1 kg P ha−1) in low yielding systems, and 0.15–0.50 g P m−2 (1.5–5.0 kg P ha−1) in higher yielding systems. Improved crop management and alternative breeding approaches may be required to achieve larger reductions in grain P concentrations in rice.

No MeSH data available.