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Juma RU, Bartholomé J, Thathapalli Prakash P, Hussain W, Platten JD, Lopena V, Verdeprado H, Murori R, Ndayiragije A, Katiyar SK, Islam MR, Biswas PS, Rutkoski JE, Arbelaez JD, Mbute FN, Miano DW, Cobb JN. Identification of an Elite Core Panel as a Key Breeding Resource to Accelerate the Rate of Genetic Improvement for Irrigated Rice. Rice (N Y) 2021; 14:92. [PMID: 34773509 PMCID: PMC8590642 DOI: 10.1186/s12284-021-00533-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 10/29/2021] [Indexed: 06/13/2023]
Abstract
Rice genetic improvement is a key component of achieving and maintaining food security in Asia and Africa in the face of growing populations and climate change. In this effort, the International Rice Research Institute (IRRI) continues to play a critical role in creating and disseminating rice varieties with higher productivity. Due to increasing demand for rice, especially in Africa, there is a strong need to accelerate the rate of genetic improvement for grain yield. In an effort to identify and characterize the elite breeding pool of IRRI's irrigated rice breeding program, we analyzed 102 historical yield trials conducted in the Philippines during the period 2012-2016 and representing 15,286 breeding lines (including released varieties). A mixed model approach based on the pedigree relationship matrix was used to estimate breeding values for grain yield, which ranged from 2.12 to 6.27 t·ha-1. The rate of genetic gain for grain yield was estimated at 8.75 kg·ha-1 year-1 (0.23%) for crosses made in the period from 1964 to 2014. Reducing the data to only IRRI released varieties, the rate doubled to 17.36 kg·ha-1 year-1 (0.46%). Regressed against breeding cycle the rate of gain for grain yield was 185 kg·ha-1 cycle-1 (4.95%). We selected 72 top performing lines based on breeding values for grain yield to create an elite core panel (ECP) representing the genetic diversity in the breeding program with the highest heritable yield values from which new products can be derived. The ECP closely aligns with the indica 1B sub-group of Oryza sativa that includes most modern varieties for irrigated systems. Agronomic performance of the ECP under multiple environments in Asia and Africa confirmed its high yield potential. We found that the rate of genetic gain for grain yield found in this study was limited primarily by long cycle times and the direct introduction of non-improved material into the elite pool. Consequently, the current breeding scheme for irrigated rice at IRRI is based on rapid recurrent selection among highly elite lines. In this context, the ECP constitutes an important resource for IRRI and NAREs breeders to carefully characterize and manage that elite diversity.
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Affiliation(s)
- Roselyne U Juma
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
- Kenya Agricultural and Livestock Research Organization, 50100-169, Kakamega, Kenya
| | - Jérôme Bartholomé
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines.
- AGAP Institut, CIRAD, INRA, Montpellier SupAgro, Univ Montpellier, Montpellier, France.
| | - Parthiban Thathapalli Prakash
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
| | - Waseem Hussain
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
| | - John D Platten
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
| | - Vitaliano Lopena
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
| | - Holden Verdeprado
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
| | - Rosemary Murori
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
- International Rice Research Institute (IRRI) C/O ILRI, Old Naivasha Road, PO Box 30709, 00100, Nairobi, Kenya
| | - Alexis Ndayiragije
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
- Institiuto de Investigação de Moçambique (IIAM), Av. das FPLM nr 2698, Recinto do IIAM, Maputo, Mozambique
| | - Sanjay Kumar Katiyar
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
- International Rice Research Institute, South Asia Hub, ICRISAT, Hyderabad, 502324, India
| | - Md Rafiqul Islam
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
- Bangladesh Office, International Rice Research Institute (IRRI), Dhaka, Bangladesh
| | - Partha S Biswas
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
- Plant Breeding Division, Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh
| | - Jessica E Rutkoski
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
- University of Illinois at Urbana-Champaign, Urbana, USA, Illinois
| | - Juan D Arbelaez
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines
- University of Illinois at Urbana-Champaign, Urbana, USA, Illinois
| | - Felister N Mbute
- Department of Plant Science and Crop Protection, University of Nairobi, PO Box 29053, 00625, Kangemi, Kenya
| | - Douglas W Miano
- Department of Plant Science and Crop Protection, University of Nairobi, PO Box 29053, 00625, Kangemi, Kenya
| | - Joshua N Cobb
- Rice Breeding Innovations Platform, International Rice Research Institute, 1301 Los Baños, Metro, DAPO Box 7777, Manila, Philippines.
- RiceTec. Inc, PO Box 1305, Alvin, TX, 77512, USA.
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Cobb JN, Juma RU, Biswas PS, Arbelaez JD, Rutkoski J, Atlin G, Hagen T, Quinn M, Ng EH. Enhancing the rate of genetic gain in public-sector plant breeding programs: lessons from the breeder's equation. Theor Appl Genet 2019; 132:627-645. [PMID: 30824972 PMCID: PMC6439161 DOI: 10.1007/s00122-019-03317-0] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 02/21/2019] [Indexed: 05/20/2023]
Abstract
The integration of new technologies into public plant breeding programs can make a powerful step change in agricultural productivity when aligned with principles of quantitative and Mendelian genetics. The breeder's equation is the foundational application of quantitative genetics to crop improvement. Guided by the variables that describe response to selection, emerging breeding technologies can make a powerful step change in the effectiveness of public breeding programs. The most promising innovations for increasing the rate of genetic gain without greatly increasing program size appear to be related to reducing breeding cycle time, which is likely to require the implementation of parent selection on non-inbred progeny, rapid generation advance, and genomic selection. These are complex processes and will require breeding organizations to adopt a culture of continuous optimization and improvement. To enable this, research managers will need to consider and proactively manage the, accountability, strategy, and resource allocations of breeding teams. This must be combined with thoughtful management of elite genetic variation and a clear separation between the parental selection process and product development and advancement process. With an abundance of new technologies available, breeding teams need to evaluate carefully the impact of any new technology on selection intensity, selection accuracy, and breeding cycle length relative to its cost of deployment. Finally breeding data management systems need to be well designed to support selection decisions and novel approaches to accelerate breeding cycles need to be routinely evaluated and deployed.
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Affiliation(s)
- Joshua N Cobb
- International Rice Research Institute, Los Banos, Laguna, Philippines.
| | - Roselyne U Juma
- International Rice Research Institute, Los Banos, Laguna, Philippines
- Kenya Agricultural and Livestock Research Organization, Nairobi, Kenya
| | - Partha S Biswas
- International Rice Research Institute, Los Banos, Laguna, Philippines
- Bangladesh Rice Research Institute, Gazipur, Bangladesh
| | - Juan D Arbelaez
- International Rice Research Institute, Los Banos, Laguna, Philippines
| | - Jessica Rutkoski
- International Rice Research Institute, Los Banos, Laguna, Philippines
| | - Gary Atlin
- Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Tom Hagen
- CGIAR Excellence in Breeding Platform (EiB), El Batan, Mexico
- International Maize and Wheat Improvement Center (CIMMYT), El Batan, Mexico
| | - Michael Quinn
- CGIAR Excellence in Breeding Platform (EiB), El Batan, Mexico
- International Maize and Wheat Improvement Center (CIMMYT), El Batan, Mexico
| | - Eng Hwa Ng
- CGIAR Excellence in Breeding Platform (EiB), El Batan, Mexico
- International Maize and Wheat Improvement Center (CIMMYT), El Batan, Mexico
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