Zinc nutrition in chickpea (Cicer arietinum): a review

Chickpea (Cicer arietinum L.) is an important grain legume that is grown and consumed all over the world. Chickpea is mostly grown in rainfed areas and marginal soils with low available zinc (Zn); however, its productivity is affected by micronutrient deficiencies in soil, particularly Zn deficiency. Zinc is a structural constituent and regulatory cofactor of enzymes involved in various plant biochemical pathways. As such, Zn deficiency impairs plant growth and development by reducing enzyme activity, disturbing ribosomal stabilisation, and decreasing the rate of protein synthesis. Moreover, Zn deficiency induces flower abortion and ovule infertility, leading to low seedset and substantial yield reductions. Nonetheless, inclusion of chickpea in cropping systems (e.g. rice-wheat), either in rotation or intercropped with cereals, improves Zn availability in the soil through the release of phosphatases, carboxylates, and protons by roots and soil microbes. This review discusses the role of Zn in chickpea biology, various factors affecting Zn availability, and Zn dynamics in soil and chickpea-based cropping systems. The review also covers innovative breeding strategies for developing Zn-efficient varieties, biofortification, and agronomic approaches for managing Zn deficiency in chickpea. Strategies to improve grain yield and grain Zn concentration in chickpea through use of different Zn-application methods-soil, foliar and seed treatments-that are simple, efficient and cost-effective for farmers are also discussed. Screening of efficient genotypes for root Zn uptake and translocation to the grain should be included in breeding programs to develop Zn-efficient chickpea genotypes.