Quantitative trait loci (QTLs) for water use and crop production traits co-locate with major QTL for tolerance to water deficit in a fine-mapping population of pearl millet (Pennisetum glaucum L. R.Br.)

Tharanya, M and Kholova, J and Sivasakthi, K and Seghal, D and Hash, C T and Raj, B and Srivastava, R K and Baddam, R and Thirunalasundari, T and Yadav, R and Vadez, V (2018) Quantitative trait loci (QTLs) for water use and crop production traits co-locate with major QTL for tolerance to water deficit in a fine-mapping population of pearl millet (Pennisetum glaucum L. R.Br.). Theoretical and Applied Genetics (TSI). pp. 1-21. ISSN 0040-5752

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Abstract

Key message Four genetic regions associated with water use traits, measured at different levels of plant organization, and with agronomic traits were identified within a previously reported region for terminal water deficit adaptation on linkage group 2. Close linkages between these traits showed the value of phenotyping both for agronomic and secondary traits to better understand plant productive processes. Abstract Water saving traits are critical for water stress adaptation of pearl millet, whereas maximizing water use is key to the absence of stress. This research aimed at demonstrating the close relationship between traits measured at different levels of plant organization, some putatively involved in water stress adaptation, and those responsible for agronomic performance. A fine-mapping population of pearl millet, segregating for a previously identified quantitative trait locus (QTL) for adaptation to terminal drought stress on LG02, was phenotyped for traits at different levels of plant organization in different experimental environments (pot culture, high-throughput phenotyping platform, lysimeters, and field). The linkages among traits across the experimental systems were analysed using principal component analysis and QTL co-localization approach. Four regions within the LG02-QTL were found and revealed substantial co-mapping of water use and agronomic traits. These regions, identified across experimental systems, provided genetic evidence of the tight linkages between traits phenotyped at a lower level of plant organization and agronomic traits assessed in the field, therefore deepening our understanding of complex traits and then benefiting both geneticists and breeders. In short: (1) under no/mild stress conditions, increasing biomass and tiller production increased water use and eventually yield; (2) under severe stress conditions, water savings at vegetative stage, from lower plant vigour and fewer tillers in that population, led to more water available during grain filling, expression of stay-green phenotypes, and higher yield.

Item Type: Article
Divisions: Research Program : Innovation Systems for the Drylands (ISD)
Research Program : West & Central Africa
CRP: UNSPECIFIED
Uncontrolled Keywords: Quantitative trait loci (QTLs), mapping population, pearl millet, water deficit, abiotic stress, plant growth, phenotyping, fine-mapping population, crop improvement
Subjects: Others > Abiotic Stress
Others > Crop Improvement
Mandate crops > Millets > Pearl Millet
Others > Water Resources
Depositing User: Mr Ramesh K
Date Deposited: 15 May 2018 05:03
Last Modified: 15 May 2018 05:03
URI: http://oar.icrisat.org/id/eprint/10662
Official URL: http://dx.doi.org/10.1007/s00122-018-3094-6
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: Work was funded by a grant from the USAID-Feed the Future Innovation Lab–Development of Abiotic Stress Tolerant Millet for Africa and South Asia. The authors are thankful to Mr. N. Pentaiah, Mr. PVD. Maheshwar Rao, and Mr. M. Anjaiah for their expert technical support. The authors thank an anonymous reviewer for the valuable suggestions. Funding was provided by Climate Resilient Pearl Millet.
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