The variation of phosphorous content, grain yield, and rhizosphere microbial biomass among durum wheat cultivars under salinity stress

ABSTRACT

The effectiveness of plant–soil synergies is largely modulated by interaction between cultivar and rhizosphere microbiome. We evaluated the agronomic performance of six durum wheat cultivars, in two semi-arid locations in Tunisia that differed in their irrigation water salinity: S1 (6 dS m⁻¹) and S2 (12 dS m⁻¹). The two-consecutive-year field experiments assessed the effects of the microbial biomass carbon (MBC), leaf phosphorus (LP) and rhizosphere phosphorus (P) on the grain yield (GY) and yield components at tillering and flowering stages. Overall, in saline conditions, cultivars differed in above- and below-ground traits, particularly, with tolerant cultivars presenting relatively greater MBC, P and LP. Furthermore, in S2, GY positively correlated with MBC (r = 0.69), LP (r = 0.80) and P (r = 0.79). Additionally, in S2, MBC positively correlated with P (r = 0.87) and LP (r = 0.85) at flowering. This result was further confirmed by multiple linear regression (step-wise) analysis, which revealed that MBC and LP were the determinant components of GY variability under S2. The present study demonstrates that LP and soil P are mandatory for improving the management of durum wheat. Salinity tolerance was largely affected by the cultivars’ rhizosphere MBC.

KEYWORDS:

• Soil and leaf phosphorus
• microbial biomass carbon
• wheat cultivars
• growth stages
• salinity stress

Acknowledgements

This study was supported in part by the Tunisian Ministry of Agriculture and the Tunisian Ministry of Higher Education, Scientific Research and Information and Communication Technologies. The authors would like to think Pr. Salah Rezgui for his useful comments and constructive suggestions concerning the paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

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