Breeding drought-tolerant pearl millet using conventional and genomics approaches: Achievements and prospects

Authors: SRIVASTAVA, RAKESH - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); YADAV, O - Central Arid Zone Research Institute; KALIAMOORTHY, S - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); GUPTA, S - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); Serba, Desalegn; CHOUDHARY, S - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); GOVINDARAJ, M - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); KHOLOVA, JANA - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); MURUGESAN, T - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); SATYAVATHI, C - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); GUMMA, MURALI - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; SINGH, RAM - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); BOLLAM, SRIKANTH - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); Gupta, Rajeev; VARSHNEY, RAJEEV - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT)

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2022
Publication Date: 4/7/2022
Citation: Srivastava, R.K., Yadav, O., Kaliamoorthy, S., Gupta, S.K., Serba, D.D., Choudhary, S., Govindaraj, M., Kholova, J., Murugesan, T., Satyavathi, C., Gumma, M.K., Singh, R.B., Bollam, S., Gupta, R., Varshney, R.K. 2022. Breeding drought-tolerant pearl millet using conventional and genomics approaches: Achievements and prospects. Frontiers in Plant Science. 13. Article 781524. https://doi.org/10.3389/fpls.2022.781524.
DOI: https://doi.org/10.3389/fpls.2022.781524

Interpretive Summary: Drought is an important environmental stress limiting crop production mainly in arid and semiarid environments of the world. The scope and intensity of drought is expected to exacerbate with the looming global climate change. Pearl millet is one of the cereal crops adapted to dry and hot climates. It is predominantly grown in Africa and Indian subcontinent and has a dual-purpose, grain for human consumption and fodder for animals. However, there is limited and scattered information on pearl millet response to drought stress at various growth stages, on physiology of yield formation under drought stress, and target traits that are paramount for further genetic improvement of the crop for drought tolerance. In this article, we reviewed and discoursed the advancements in conventional breeding, progress in genomic resources development and application, high-throughput phenotyping, and the strategic use of genetic resources that can further enhance the development and delivery of high-yielding and drought-tolerant pearl millet cultivars. The comprehensive information presented herein serve as a reference for scientists studying different drought tolerance features of pearl millet.

Technical Abstract: Pearl millet [Pennisetum glaucum (L.) R. Br.] is a C4 crop cultivated for its grain and stover in crop-livestock-based rainfed farming systems of tropics and sub-tropics in the Indian sub-continent and sub-Saharan Africa. The intensity of drought is predicted to further exacerbate climate change in growing regions, necessitating a greater focus on pearl millet breeding for drought tolerance. The nature of drought in the different target populations of pearl millet growing environments (TPE) is highly variable in its timing, intensity and duration. Pearl millet response to drought at various growth stages has been studied comprehensively. Dissection of drought tolerance physiology and phenology insights has helped in understanding the yield formation process under drought conditions. The overall understanding of TPE and differential sensitivity of various growth stages to water stress helped to identify target traits for manipulation through breeding in pearl millet for drought ecology. Recent advancement in high-throughput phenotyping platforms has made it realistic to screen large populations/germplasm for drought adaptive traits. The role of adapted germplasm has been emphasized for drought breeding as the measured performance under drought stress is largely an outcome of adaptation to stress environments. Hybridization of adapted landraces with selected elite genetic material has been testified to amalgamate adaptation and productivity. Substantial progress has been made towards the development of genomic resources that have been used to explore genomic variation, linkage mapping (QTLs), marker-trait association (MTA), and genomic selection (GS) in pearl millet. High-throughput genotyping (HTPG) platforms are now available at a low cost offering enormous opportunities in applying MAS in conventional breeding programs targeting drought tolerance. Next-generation sequencing (NGS) technology, micro-environmental modelling, and pearl millet whole genome re-sequence information covering circa 1,000 wild and cultivated accessions have helped to a greater understanding of germplasm, genomes, genes and markers. Their application in molecular breeding would lead to the development of high-yielding and drought-tolerant pearl millet cultivars. This review examines how the strategic use of genetic resources, modern genomics, molecular biology and shuttle breeding can further enhance the development and delivery of drought-tolerant cultivars.