Leaf transpiration plays a role in phosphorus acquisition among a large set of chickpea genotypes

Low availability of inorganic phosphorus (P) is considered a major constraint for crop productivity worldwide. A unique set of 266 chickpea (Cicer arietinum L.) genotypes, originating from 29 countries and with diverse genetic background, were used to study P-use efficiency. Plants were grown in pots containing sterilized river sand supplied with P at a rate of 10gPg(-1) soil as FePO4, a poorly soluble form of P. The results showed large genotypic variation in plant growth, shoot P content, physiological P-use efficiency, and P-utilization efficiency in response to low P supply. Further investigation of a subset of 100 chickpea genotypes with contrasting growth performance showed significant differences in photosynthetic rate and photosynthetic P-use efficiency. A positive correlation was found between leaf P concentration and transpiration rate of the young fully expanded leaves. For the first time, our study has suggested a role of leaf transpiration in P acquisition, consistent with transpiration-driven mass flow in chickpea grown in low-P sandy soils. The identification of 6 genotypes with high plant growth, P-acquisition, and P-utilization efficiency suggests that the chickpea reference set can be used in breeding programmes to improve both P-acquisition and P-utilization efficiency under low-P conditions. Low availability of phosphorus (P) is a major constraint for crop productivity worldwide, and there is a need to improve P-use efficiency. Using a unique set of 266 chickpea genotypes, our study identified 6 genotypes with high P-acquisition and P-utilization efficiency, suggesting that the chickpea reference set can be used in breeding programs to improve P-use efficiency under low-P conditions. For the first time, our study has demonstrated the significance of leaf transpiration in P acquisition likely via mass flow in chickpea grown in low-P sandy soils.