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Pearl millet is a very important crop of arid and semi-arid regions in Asia and Africa where it is the basis of food security of millions of people inhabiting in harsh and environmentally fragile ecosystem. Genetic resources of pearl millet including landraces, improved elite material, traditional cultivars, genetic stocks and wild relatives are very rich and, therefore, their characterization, documentation, conservation and distribution is very essential to ensure utilization in breeding programmes. This review assesses the status of pearl millet genetic resources, and identifi es the gaps in their collection, conservation and utilization. A total of 56,580 accessions (including possible duplicates) of pearl millet in 70 genebanks of 46 countries across world are available. Landraces represent the largest part of pearl millet germplasm, followed by breeding/research material and wild relatives. The Indian national collection includes 7,059 accessions at the National Bureau of Plant Genetic Resources (NBPGR), New Delhi. Global collections managed by ICRISAT comprise of 22,888 pearl millet accessions from 51 countries. However, only a very small fraction of these accessions has been utilized so far. Critical assessment of collection for geographical and trait-diversity gaps using various GIS tools revealed several gaps in germplasm collection from Asian and African continents. Almost all cultivated accessions have been characterized for 23 morpho-agronomic characters following prescribed pearl millet descriptors. A large variation exists for phenotypic and phenological traits among available germplasm. In general, Indian pearl millet landraces have mainly contributed for earliness, high tillering, high harvest index and local adaptation; whereas African material has been a good source of bigger panicles, large seed size, and disease resistance. Systematic evaluation and screening of germplasm has led to the identifi cation of specifi c sources of better grain quality, resistance to diseases and tolerance to abiotic stresses like drought and heat. These germplasm sources continue to play a critical role in crop improvement programmes across the world. Formation of trait-specifi c gene pools, core and minicore collections are likely to enhance the utilization of genetic resources to a greater degree. Strategies for further enriching the germplasm and increasing its use are discussed.

SUMMARYNumber of nodules and leghaemoglobin content of nodules increased with increasing Zn application up to 7·5 μg/g soil. Dry-matter yield and N fixation increased with Zn up to 10 μg/g soil. Both nodulation and N fixation decreased at higher levels. Soil N content showed an initial depletion but increased during the late season. Critical lower and upper levels for maximum N fixation were 1·75–2·5, and 10–14 μg of DTPA extractable Zn/g soil, respectively. In the present studies 5–10 μg Zn/g soil was sufficient for maximum N fixation in chickpea.