Independent Science for Animals, Farms and Ecosystems.
Don’t Force Nature to Fit the System
Fit Genetics and Management to the Environment
Alvaro Garcia DVM PhD
Abstract
Agricultural production is often approached by first establishing a production goal and then modifying genetics and management to achieve it. History suggests that reversing this perspective can lead to more resilient production systems. From the Dust Bowl and the introduction of drought-adapted Russian wheat to N'Dama and Brahman cattle and the diversity of Mexican maize, successful agriculture repeatedly demonstrates the importance of matching genetics and management to environmental conditions. Modern genetics and technology provide extraordinary opportunities to increase production, but biological potential has value only when it can be consistently expressed. Rather than pursuing maximum performance under ideal conditions, production systems should emphasize the interaction among genetic potential, environmental limitations, and management. The objective is not lower production, but production that is consistent, profitable, and well matched to the environment.
Introduction
Agriculture has always involved a tension between what we want a plant or animal to produce and what the environment can support. We often begin with the production target. We want more beef, more milk, more grain, more pounds per acre, or more animals per hectare. Then we select genetics and design management systems around achieving that target.
But there is another way to think about agriculture. Instead of asking, “How do we make this environment produce what we want?” we can ask, “What genetics and management will allow this environment to produce at its best?” The distinction is important. Agricultural history provides remarkable examples of what happens when production systems ignore environmental limitations, and what becomes possible when genetics and management are selected to work with them.
Two Lessons from the Great Plains
The Dust Bowl is perhaps the best-known example of what can happen when management becomes poorly matched to the environment. During the 1920s, high crop prices and favorable weather encouraged farmers across the Great Plains to plow large areas of native grassland, much of it for wheat production. The native prairie had evolved under the conditions of the region. Its perennial grasses and extensive root systems protected the soil. When severe drought arrived in the 1930s, much of that vegetation was gone. Crops failed, soil was exposed, and strong winds carried enormous quantities of topsoil across the Plains.
The response was not to conclude that agriculture was impossible there. Instead, the production system changed. Soil conservation, crop rotations, erosion control, residue management, and other practices became increasingly important. The lesson was that the Great Plains could be highly productive, but they could not simply be managed as though they were a wetter and more forgiving agricultural region.
Another Great Plains story illustrates the other side of the equation. In 1898, USDA plant explorer Mark A. Carleton traveled to Russia and returned with durum and hard red wheat varieties. Their value was not simply high yield potential. They possessed characteristics, including drought tolerance, that made them particularly useful under American growing conditions. These introductions subsequently contributed to the expansion of wheat production in parts of the Great Plains and Northwest.
The contrast between these two stories is revealing. In one case, agriculture attempted to impose a production system that was poorly suited to the environment. In the other, genetics were introduced because they were better suited to the conditions that existed.
The answer was not necessarily to produce less. It was to find plants capable of producing successfully within the environmental limitations they faced.
Adaptation does not mean accepting low production. It means finding production potential that is compatible with the environment.
When Adaptation Becomes an Advantage
The same principle becomes particularly clear in livestock production. In West Africa, N'Dama cattle developed in regions where tsetse flies transmit trypanosomiasis, a disease that can severely restrict cattle production. N'Dama possess a genetically based ability known as trypanotolerance, allowing them to survive, reproduce, and remain productive under disease pressure that can severely affect susceptible cattle.
This changes the definition of a “good” animal. An animal may possess exceptional growth or milk-production potential under ideal conditions, but if it cannot remain healthy and fertile in the environment where it must live, how valuable is that potential? Another animal may have somewhat lower maximum production but remain healthy, reproduce consistently, and require fewer interventions. Under those conditions, disease resistance may be worth more than another increment of growth.
The development of Brahman-influenced cattle in the American South takes this idea one step further. European cattle brought desirable beef-production characteristics, but the hot and humid Gulf Coast presented challenges from heat, humidity, insects, ticks, parasites, and disease. Brahman cattle brought traits that made them particularly well suited to those conditions, including heat tolerance and tick resistance.
American breeders did not have to choose between productive European cattle and environmentally adapted Brahman cattle. By combining genetics, they sought animals that could retain desirable beef-production characteristics while gaining greater environmental adaptation. That is an important distinction. Production and adaptation are not competing objectives. Good genetic selection attempts to combine them.
The objective, therefore, is not to find the best animal in the abstract. It is to find the animal capable of expressing valuable production traits under the environment and management system in which it will live.
Crop diversity reinforces the same point. Mexico, the center of origin and diversity for maize, contains an extraordinary range of maize varieties developed under different combinations of altitude, temperature, rainfall, growing seasons, and other environmental conditions. Over generations, farmers were not selecting toward one universal definition of the best maize. They were selecting plants that worked where they lived.
A variety adapted to a high-altitude environment may perform very differently in a hot, low-elevation region or under a different rainfall pattern. The diversity itself demonstrates the principle: there is no single best genotype independent of environment. There are genetics better suited to particular environments.
Rethinking What We Mean by Performance
Modern agriculture gives us tremendous genetic power. We can select cattle for growth, milk production, fertility, feed efficiency, carcass characteristics, disease resistance, and heat tolerance. Crops can be selected for yield, maturity, drought tolerance, disease resistance, nutrient efficiency, and numerous other characteristics.
That ability can also create a temptation to focus on maximum production potential without asking whether the environment can consistently support it. An animal with exceptional genetic potential still requires adequate feed, water, minerals, health, and an appropriate thermal environment. A high-yielding crop still depends on rainfall, soil fertility, temperature, disease pressure, and a suitable growing season. Genetics set the potential. Environment shapes the outcome.
This is where agriculture differs fundamentally from manufacturing. In a factory, many operating conditions can be controlled within narrow limits. Biological production does not offer us that luxury. Rainfall and temperatures fluctuate. Soils differ. Forage availability changes. Droughts occur. Diseases and parasites challenge animals and plants. The objective cannot be to eliminate all environmental variation. It should be to develop production systems resilient enough to perform despite the variation that cannot be eliminated.
Genetics and management then become complementary rather than separate tools. We can select cattle that maintain fertility and body condition when temperatures rise or forage becomes limited, animals with resistance to locally important diseases and parasites, and crops capable of maintaining production under heat or water stress. Management can complement those genetics through stocking rates, nutrition, grazing systems, planting dates, crop rotations, fertility programs, housing, cooling, and other interventions appropriate to local conditions.
This also changes how performance should be measured. Maximum milk yield, average daily gain, or crop yield under favorable conditions tells us something important, but not everything. We also need to know what happens when conditions are less favorable. Can the cow remain fertile and maintain body condition? Can the calf continue growing when forage quality declines? Can a crop maintain acceptable yield during drought? Can an animal or plant perform consistently without requiring extraordinary levels of purchased inputs or intervention?
These traits may not always produce the highest number in an individual production cycle. Over time, however, they can provide something equally valuable: consistency. And consistency matters economically.
Better-Matched Production
The Dust Bowl, Russian wheat, N'Dama cattle, Brahman cattle, and Mexican maize span different species, continents, and periods of agricultural history. What connects them is not a rejection of high production or improved genetics. It is recognition that biological potential has value only when it can be expressed under the conditions where production occurs.
That principle may be particularly important today. Modern genetics allow extraordinary levels of production, while technology gives us unprecedented ability to modify the environment through irrigation, nutrition, housing, cooling, disease control, and other interventions. These are huge advantages. But there comes a point when continually modifying the environment to accommodate poorly matched genetics may become biologically difficult or economically expensive.
The alternative is not to accept lower production, but to pursue production that can be sustained under the conditions that exist. A cow that maintains production, fertility, and body condition during heat or periods of limited forage may ultimately be more valuable than one capable of greater peak production but requiring substantially more intervention. A crop that yields slightly less under ideal conditions but maintains production during drought may contribute more over several growing seasons. The same principle applies to stocking rates, grazing systems, crop rotations, housing, nutrition, and many other management decisions.
This changes the question we should ask when choosing genetics or designing a production system. Instead of focusing only on what can produce the most, we should ask what can produce consistently and profitably under the conditions we have. That does not mean accepting lower production or slowing genetic progress. It means recognizing that production potential has little value if it cannot be expressed consistently in the environment where the animal or crop must perform.
The challenge, therefore, is not to force nature to fit the production system, but to select genetics and management that make the best use of the resources and conditions available. In agriculture, the environment is not an obstacle to production. It is part of the production system.
Further reading
USDA Agricultural Research Service. “Conserving the World's Plants.” Historical documentation of Mark A. Carleton's 1898 plant exploration in Russia and the introduction of Russian wheat varieties into the United States, including their importance to drought-prone regions.
USDA Natural Resources Conservation Service. “A Brief History of NRCS.” Historical documentation of the Dust Bowl, soil erosion crisis, and development of federal soil conservation programs.
Food and Agriculture Organization of the United Nations. “Proceedings of the FAO Expert Consultation on the Genetic Aspects of Trypanotolerance.” Evidence concerning the genetic trypanotolerance of N'Dama cattle and their ability to maintain production under tsetse challenge.
Texas State Historical Association. “Brahman Cattle.” Handbook of Texas Online. Historical information on Brahman cattle, their adaptation to the Texas climate, heat tolerance, tick resistance, and use in American cattle production.
CIMMYT. “Climatic Adaptation and Ecological Descriptors of 42 Mexican Maize Races.” Research documenting relationships between Mexican maize races and environmental variables including altitude, temperature, rainfall, and growing-season conditions.
https://knowledgecenter.cimmyt.org/cgi-bin/koha/opac-detail.pl?biblionumber=60475