Genetic Intensification

A rice plant being propagated using tissue culture. Credit, IRRI.

A rice plant being propagated using tissue culture. Credit, IRRI.

For thousands of years farmers have sought to shape the genotype (the genetic makeup of an organism with reference to its traits) and, as a result, the biological, chemical and physical characteristics of crop varieties and livestock breeds. The process of genetic inheritance (the transmission of characteristics or qualities from parents to offspring) allows farmers and breeders to improve food security by increasing both yields and the nutritive qualities of crop varieties and livestock breeds.[1] Soon after the earliest domestication of cereal grains, humans began to recognize degrees of superiority in their fields and saved seed for future planting seasons.

Modern plant breeding only dates back about 50 years. The role of pollination and fertilization in the process of reproduction was not well understood even 100 years ago, and it was not until the early part of the 20th century that the laws of genetic inheritance were applied toward the improvement of plants. Today, plant breeding aims to develop improved crop cultivars (deliberate cultivated varieties) to satisfy a range of needs and overcome a multitude of challenges. For example, breeders develop cultivars with improved yields and tolerance to drought or resistance to diseases in order to reduce the risks presented by increased food demand, diminishing supplies of good quality land and water, pest and disease outbreaks, and climate change. Soil quality can also be enhanced by varieties bred to enable nitrogen uptake and fixation or human nutrition can be improved through biofortification which adds or raises the levels of micronutrients present in a staple crop.

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Milking a cow once the calf begins to suckle in Tanzania. Credit, T. Cooper, ILRI.

Through conventional plant breeding, beneficial genes have been preserved and brought into association with other complementary genes from close relatives. The earliest approach was to select the seeds from the best performing plants for next year’s crop. Over time new and better cultivars were created containing superior genes and gene combinations. Occasionally natural crossing or hybridisation occurred between two species, for example between a wild wheat and a wild grass producing bread wheat varieties. These were then subject to intensive human selection. In the last century humans began to deliberately hybridise different varieties and species. This concentration of beneficial genes in varieties and breeds is the essence of Genetic Intensification. Since the cellular and molecular revolution over the last half century, conventional breeding has been augmented by forms of biotechnology for both crops and livestock.[2]

Genetic Intensification is one of the 3 pillars of Sustainable Intensification, alongside Ecological Intensification and Socio-Economic Intensification. Genetic Intensification includes ‘conventional plant breeding,’ ‘biotechnology,’ and ‘livestock breeding’ which incorporates elements of both breeding technologies. Conventional plant breeding can occur through a variety of approaches and for a number of objectives such as with participatory plant breeding, improving seeds through hybridisation or enhancing their nutritional properties with biofortification.

Rice leaf samples of transgenic lines that will be  subjected to DNA extraction in the laboratory. Credit, IRRI.

Rice leaf samples of transgenic lines that will be subjected to DNA extraction in the laboratory. Credit, IRRI.

Biotechnology is the application of the revolution in cellular and molecular biology that uses our knowledge of DNA and RNA (genetic information) to identify the basis for cultivating desired traits in plants and animals. This field includes several different technologies and processes for gene identification, transfer and insemination such as marker aided selection, tissue culture, and recombinant DNA.

Intensification of livestock breeding is the concentration of beneficial genes in livestock breeds, in order to sustainably increase the productivity of livestock with little or no increase in the amount of land devoted to livestock fodder and grazing. Livestock breeds can be improved through a number of proven technologies such as artificial insemination, cross breeding ‎and embryo transfer.

References
  1. [1] Agriculture for Impact 2013, Sustainable Intensification: A New Paradigm for African Agriculture, A Montpellier Panel Report, London.
  2. [2] Agriculture for Impact 2013, Sustainable Intensification: A New Paradigm for African Agriculture, A Montpellier Panel Report, London.