Envis Centre, Ministry of Environment & Forest, Govt. of India

Printed Date: Sunday, December 5, 2021

Agri & Domesticated Biodiversity

          Genetic resources of crops/livestock include both wild and domesticated gene pools. They are the reservoirs of valuable genes, which could be of immense help in the genetic improvement of domesticated varieties of crops and breeds of animals. These also include hundreds of races, subspecies, local varieties and breeds of various species. They can be domesticated varieties or breeds directly used by the mankind or wild relatives of crop plants or domesticated animals.  

          Human society will continue to depend on biodiversity of wild relatives of cultivated crops or domesticated animals, apart from those that are already domesticated. In addition to this, dependence on biological diversity for food, fibre, fuel, shelter, medicine and several other day-to-day needs would last forever. Therefore, maximum attention needs to be given to the conservation of species diversity in nature. Variations within a species are not extensively conserved, mainly because of lack of understanding of the variability or uniqueness of the variations existing within a species, either in the nature or in domesticated conditions. It is the genetic diversity which exists within the individuals of a particular species that allows its populations of a species to adapt to varied environmental conditions.  

           The livestock, fruits, vegetables, grains, pulses, etc. of the State are all derived from the diverse and healthy natural resources of our ecosystems. Wild plants and animals are diversifying for thousands of years due to changes in ecosystems in which they live. While some of them are cultivated or domesticated, some of the obsolete varieties (in the case of plants) and breeds (in the case of animals and birds) are sources of important genetic material to improve the strains or breeds presently grown. Most of the improved varieties used today are synthetic or hybrid types, derived by incorporating useful genes or selections made to produce better quality of products or forms with longer shelf life or having better resistance to insect pests or diseases and adaptation to varied environments. 

              The wealth of genetic diversity presently available in the State in the form of domesticated crops or breeds of animals together with their wild relatives is not fully documented. According to Vavilov (1926), about 160 species of domesticated plants and animals have originated in India . Kerala State, being an integral part of the Western Ghats, has a wide variety of crop plants, domesticated animals and also their wild relatives. Plant genetic resources represent the sum total of diversity accumulated through years of diversification under domestication and natural selection. This assemblage of genetic diversity of economic plants and their wild relatives, including the medicinal and aromatic plants, presents an enormous wealth of genetic variation for use in crop improvement programmes and for catering to the unknown needs of the future. A gene pool of crop plants and livestock along with their local breeds, wild relatives, land races, bio-control agents and those offering vital ecosystem services such as pollination and nutrient recycling all form a part of agribiodiversity, which is an integral part of the total biodiversity (Daniels, et al ., 1996). In Kerala, there exists two unique systems for conservation of biodiversity in general, and specifically domesticated biodiversity, in the form of homestead gardens and sacred groves, even though so far no scientific attempt has been made to understand the inter-dependence of different components of these two systems and the human beings. 

            The Indian subcontinent is the center of domestication of over 12 crop plants as known from archaeological records (Dhillon and Kochhar, 2001). The erosion of crop biodiversity, and especially domesticated biodiversity, is evident in the increased proportion of land devoted to high-yielding generally uniform varieties. In order to maintain productivity under varying climatic regimes, all components of crop diversity need to be conserved. 

          Domesticated biodiversity comprises of a wide range of natural resources including plants, animals, fishes and micro-organisms. These resources are distributed in diverse agro-ecological systems throughout the State. The agro-ecosystems range from coastal region to the plains and in the hills. There is need for systematic collection of available information, development of database at village, block, taluk, district, State and regional levels and to put the same in place for the whole of the country. A user-friendly format for information generation has also to be developed and the database needs to be updated from time to time.

          Therefore, the agri- and domesticated biodiversity of the State is quite rich, as more than 74 per cent of the total land area of Kerala is having various crops grown for domestic consumption or for sale. However, because of the highly fragmented and disturbed nature of the land area due to the population explosion and unplanned developmental activities, drastic shrinkage in the total cultivated land has taken place, especially in the recent times. At the same time, diversity of crops has increased substantially and there is also a tendency to shift from one crop to another, depending on the financial gains and ignoring the land and site suitability, often compensated by various inputs like fertilizers, pesticides, insecticides, improved varieties, and so on. While paddy remains as the major crop of the State, the area under its cultivation has shrunken drastically and most of the indigenous varieties have also been replaced by improved and genetically manipulated strains of short life span. Same is the situation with regard to the second major crop of the State, namely coconut, for which there is also a major disease called 'Kattu-veezhcha' affecting both indigenous and improved varieties. The natural habitats and areas of cultivation of both these major crops are also converted into plantations of rubber, pineapple, etc. which are perennial crops. There are also hundreds of species of fruit trees, horticultural species, garden plants and economic plants like Pineapple, Vanilla, Safed Musli, etc., grown in the midlands and coastal belt of the State, replacing the rich assemblage of indigenous cultivated crops which once flourished in these zones of the State. In brief, degradation and transformation of the agricultural ecosystem, land conversions, introduction of exotics, narrowing of the genetic base of traditional crop species and mechanized farming have negatively affected the richness of the agribiodiversity of the State and removed several wild relatives of crop plants, many of which are also seen in the forested Highlands of the State.


The major causes for the loss of indigenous agri- and domesticated biodiversity can be summerised as follows.

  •  Degradation of the native agri-ecosystems by introduction of exotic/improved  varieties and application of chemical fertilizers, insecticides, pesticides, etc.
  • Large conversion of agricultural lands for non-agricultural purposes. 
  • Introduction of exotic crops for economic gains, ignoring site suitability. 
  • Mechanised farming resulting in total removal of associated species. 
  • Narrowing the genetic base of indigenous crops by encouraging cultivation of breeds and improved varieties.  

            The faunal component of agri- and domesticated biodiversity has also changed substantially from that of the past. The cattle population of the State has undergone the maximum change in this context. Almost all the indigenous strains of cattle, like the well known Vechoor cow reared in the State are now replaced by improved strains like the Jersy, for the sake of more yield, irrespective of the quality of products and their adaptability to the native ecosystems and plant species on which they feed. Similarly, there are introductions of exotic strains of pig, chicken, pet dogs, goat, etc. replacing the native strains and their varied germplasm in the State. In order to sustain such introductions, the inputs given like synthetic diets, insecticides, pesticides, artificial feeds, etc. rendered the soil and the environment of the State unsuitable for the survival and growth of native species, even if their re-introduction is attempted at a later stage. The most glaring example of such an introduction is the present cattle population of the State, which has totally replaced all indigenous varieties. At the same time, due to the change in the agricultural system and other land uses, their rearing with the help of artificial feeds has become essential, adding more burdens to the farmers.