Darwinian Agriculture’s Three Core Principles

Author(s):  
R. Ford Denison

This chapter introduces the three core principles of Darwinian agriculture. First, natural selection is fast enough, and has been improving plants and animals for long enough, that it has left few simple, tradeoff-free opportunities for further improvement. Therefore, implicit or explicit acceptance of tradeoffs has been and will be key to crop genetic improvement, through biotechnology or traditional plant breeding methods. Second, competitive testing of individual adaptations by natural selection is more rigorous than nature's testing of natural ecosystems merely by endurance. Although testing by endurance shows sustainability, there may still be considerable room for improvement. Third, we should hedge our bets against future uncertainty with a greater variety of crops and of research approaches. The chapter argues that this bet-hedging will require allocating some land and other resources to crops and research programs that seem less promising today but may outperform today's winners if conditions change.

Author(s):  
R. Ford Denison

This chapter summarizes the book's main conclusions and cautions against exclusive reliance on any single approach. The book's central thesis is that nature's wisdom is found primarily in competitively tested individual adaptations, in wild species and sometimes still in cultivated ones, rather than in the overall structure of natural ecosystems. It notes how some biotechnology advocates underestimate the perfection of existing individual adaptations and suggests that most near-term opportunities for genetic improvement of crops or livestock will involve tradeoffs that had constrained natural selection in the past. The chapter considers two basic approaches to the problem of varying environments: phenotypic plasticity and bet-hedging. It also discusses bet-hedging in food production, the bet-hedging benefits of organic farming and animal agriculture, and the use of diversity for bet-hedging in agricultural research. Finally, it describes traditional agricultural sciences that have been more receptive to input from evolutionary biology than biotechnology has.


Author(s):  
R. Ford Denison

This book proposes new approaches to improving agriculture based on the principles of evolutionary biology and natural selection. It argues that two popular approaches to improving agriculture, biotechnology and traditional plant breeding, have tended to ignore evolutionary tradeoffs—that is, cases where an evolutionary change that is positive in one context is negative in another—and that both of them would benefit from greater attention to evolution. Whether we focus on genetic improvement of crops or better management of agricultural ecosystems, the book emphasizes the need to identify (and sometimes accept) tradeoffs that constrained past evolution in order to find new solutions to agricultural problems. It also considers some of the challenges facing agriculture, such as resource-use efficiency and food security. This chapter provides an overview of the book.


2002 ◽  
Vol 357 (1421) ◽  
pp. 709-718 ◽  
Author(s):  
Egbert Giles Leigh ◽  
Geerat Jacobus Vermeij

Three types of evidence suggest that natural ecosystems are organized for high productivity and diversity: (i) changes not previously experienced by a natural ecosystem, such as novel human disturbances, tend to diminish its productivity and/or diversity, just as ‘random’ changes in a machine designed for a function usually impair its execution of that function; (ii) humans strive to recreate properties of natural ecosystems to enhance productivity of artificial ones, as farmers try to recreate properties of natural soils in their fields; and (iii) productivity and diversity have increased during the Earth's history as a whole, and after every major biotic crisis. Natural selection results in ecosystems organized to maintain high productivity of organic matter and diversity of species, just as competition among individuals in Adam Smith's ideal economy favours high production of wealth and diversity of occupations. In nature, poorly exploited energy attracts more efficient users. This circumstance favours the opening of new ways of life and more efficient recycling of resources, and eliminates most productivity–reducing ‘ecological monopolies’. Ecological dominants tend to be replaced by successors with higher metabolism, which respond to more stimuli and engage in more varied interactions. Finally, increasingly efficient predators and herbivores favour faster turnover of resources.


2019 ◽  
Vol 16 (154) ◽  
pp. 20190054 ◽  
Author(s):  
Yuriy Pichugin ◽  
Hye Jin Park ◽  
Arne Traulsen

The mode of reproduction is a critical characteristic of any species, as it has a strong effect on its evolution. As any other trait, the reproduction mode is subject to natural selection and may adapt to the environment. When the environment varies over time, different reproduction modes could be optimal at different times. The natural response to a dynamic environment seems to be bet hedging, where multiple reproductive strategies are stochastically executed. Here, we develop a framework for the evolution of simple multicellular life cycles in a dynamic environment. We use a matrix population model of undifferentiated multicellular groups undergoing fragmentation and ask which mode maximizes the population growth rate. Counterintuitively, we find that natural selection in dynamic environments generally tends to promote deterministic, not stochastic, reproduction modes.


2021 ◽  
Vol 32 (Issue 2) ◽  
pp. 8-12
Author(s):  
P. Rimieri

Tall fescue (Festuca arundinacea Schreb.) is represented in Argentina by adapted populations of the continental morphotype, which are long persistent. It is the main perennial forage species cultivated in the temperate region of the country, producing forage for extensive grazing. The development of fescue plant breeding and its contribution to the achievement of higher productivity and better nutritional value with modern synthetic cultivars was the aim of this project. The characters considered were: adaptation and persistence in adverse environments, digestibility, leaf softness and tolerance to rust. The most representative cultivars of the stages and selection criteria considered in this work were: Pergamino El Palenque MAG, Palenque Plus INTA, Brava INTA, Baguala and Luján INTA. Key words: tall fescue, plant breeding, cultivars, germplasm.


2022 ◽  
Author(s):  
Irene S. Breider ◽  
R. Chris Gaynor ◽  
Gregor Gorjanc ◽  
Steve Thorn ◽  
Manish K. Pandey ◽  
...  

Abstract Some of the most economically important traits in plant breeding show highly polygenic inheritance. Genetic variation is a key determinant of the rates of genetic improvement in selective breeding programs. Rapid progress in genetic improvement comes at the cost of a rapid loss of genetic variation. Germplasm available through expired Plant Variety Protection (exPVP) lines is a potential resource of variation previously lost in elite breeding programs. Introgression for polygenic traits is challenging, as many genes have a small effect on the trait of interest. Here we propose a way to overcome these challenges with a multi-part pre-breeding program that has feedback pathways to optimise recurrent genomic selection. The multi-part breeding program consists of three components, namely a bridging component, population improvement, and product development. Parameters influencing the multi-part program were optimised with the use of a grid search. Haploblock effect and origin were investigated. Results showed that the introgression of exPVP germplasm using an optimised multi-part breeding strategy resulted in 1.53 times higher genetic gain compared to a two-part breeding program. Higher gain was achieved through reducing the performance gap between exPVP and elite germplasm and breaking down linkage drag. Both first and subsequent introgression events showed to be successful. In conclusion, the multi-part breeding strategy has a potential to improve long-term genetic gain for polygenic traits and therefore, potential to contribute to global food security.


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