Wild Cicer species exhibit superior leaf photosynthetic phosphorus- and water-use efficiencies compared with cultivated chickpea under low-phosphorus conditions

Abstract

Domesticated chickpea cultivars exhibit limited genetic diversity. This study evaluated the effects of chickpea domestication on phosphorus (P)-use efficiency (PUE) under low-P conditions, using a diverse Cicer collection, including wild species. Two wild Cicer species – 54 C. reticulatum accessions and 15 C. echinospermum accessions, and seven domesticated C. arietinum accessions were grown in low-P soil. All three species exhibited significant variation in physiological PUE, leaf gas exchange characteristics, photosynthetic PUE (PPUE), and photosynthetic N-use efficiency (PNUE), with greater variation in wild Cicer species than in domesticated C. arietinum. Domestication increased shoot growth and total leaf area but reduced root mass ratio. Compared with domesticated C. arietinum, wild Cicer species had lower stomatal conductance and higher leaf mass per area, associated with lower intercellular CO2 concentrations and higher water-use efficiency (WUE). Elevated leaf nitrogen concentrations in wild Cicer were likely associated with enhanced photosynthetic capacity, partially compensating for reduced stomatal conductance. Wild Cicer species demonstrated higher PPUE but lower PNUE than domesticated chickpea, with increased WUE exhibiting a trade-off with PNUE. These findings highlight the potential of wild Cicer species as valuable genetic resources for enhancing PPUE in chickpea improvement programmes.