13 Agrobiodiversity

Dr Sunil Mittal

1. Introduction

2.Agrobiodiversity in India

3. The Role of Agricultural diversity

4. Conservation of agrobiodiversity

4.1. Ex situ conservation

4.2. In situ conservation

5. Registration of biodiversity at local level

6. Community Recognition and awards

7. Indian National Gene bank

8.  National Active germ-plasm sites

9.  Guidelines for sending seed samples for conservation

10.Indian Scenario

1. Introduction

Biological diversity deals with the degree of variability of plant and animal life in biosphere. This variation in diversity can be observed at genetic level, species and ecosystem level. Biodiversity facilitates the renewal of water, air, soil, and also allows the free recycling. Human interference in nature gave rise to a subset of biodiversity which is known as agro-biodiversity. Agricultural biodiversity or agro-biodiversity includes:

Fish species, harvested crop varieties, livestock breeds, and wild resources.

Non-harvested species that support food provision e.g., soil micro-biota, pollinators and greenflies, bees, butterflies, earthworms.

Non-harvested species that support agricultural, forest, pastorals and aquatic ecosystems.

Agrobiodiversity is the central part of overall biodiversity. Agro-biodiversity encloses the variety and variability of plants, animals, and micro-organisms. The variability is necessary for sustaining the functions of the agro-ecosystem. The integral parts of agro-biodiversity are culture and local knowledge. Therefore, it can be said that the variety and variability of plants, animals, and micro-organisms used directly or indirectly for food and agriculture (livestock, crops, fisheries, and forestry) is termed as agro-biodiversity.

Or

Diversity within agriculture related species, agricultural systems and individuals within species is defined as agro-biodiversity. It includes all those organisms that are associated with agricultural and food production. For e.g., plants, animals, insects, reptiles, amphibians, soil organisms and other micro-organisms. It also includes wild and domesticated species that serve as genetic stocks for several important traits.

Agrobiodiversity is responsible for:

• Firmness in agriculture production
• Livelihood of farmers
• Sustainable development

Agro-biodiversity provides opportunity for nutrient recycling, protects against abiotic and biotic stress conditions, controls weeds and maintains soil productivity. Agrobiodiversity is having an important aspect that it provides genetic resources. These genetic resources have potential for making improvements in agricultural productivity.

2. Agrobiodiversity in India

India comes under the category of those countries that are rich in biodiversity. This section will highlight the diversity in crops and plants. Out of eight diversity centers, India was amongst them as discovered by Vavilov. The major and minor crops endemic to the country include rice, pulses, millets, vegetables, Indian mustard, fruits, tuber crops, spices, fibre crops and Cannabis. Moreover, World conservation monitoring centre also published a list of the crops that were having Indian origin. These are Mango, Tea, Taro, Rice, finger millet, seasem seed, pepper, pear, lemon, apple, eggplant and cardamom, cucumber, and mustard seed.

The crops that are cultivated at present in the country have been derived from two sources

i)  Indigenous

ii)   Introduced

Indigenous crops have invaded the Indian land from various countries like Africa, China, Europe, Western Asia and the new world.

Crops were introduced in the country by Spanish and Moughals, Britishers and Portuguese. The introduced crops include pear, apple, peach, apricot, maize, almond, sweet potato, potato, garlic, chilies, onion, lentil and tomato. The introduced species have undergone the process of diversification.

3.  The Role of Agricultural Biodiversity Agrobiodiversity plays following important roles:

• Agro-biodiversity has significant economic value due to the market price of products.
• It also provides jobs and incomes for numerous people.
• Forestry and timber sectors also provide million jobs (including furniture and paper production).
• Diversity of life forms and their heritable traits provides precious resources. These resources can be used in future and forms a foundation for modernization and greater economic activity.

4.  Conservation of Agrobiodiversity

The available genetic resources need to be conserved for sustainable use. Two basic approaches are used for the conservation purpose. These are

i)   ex-situ

ii)   in-situ

Long term storage comes under ex-situ conservation while in-situ conservation involves storage under natural conditions.

4.1. Ex-situ conservation

• The primary aim of ex- situ conservation is to maintain germ-plasm materials alive as for longer period of time and to decrease the occurrence of regeneration that may result in the loss of genetic diversity.
• For the past several years, ex-situ methods were primarily focused on the conservation of cereal’s seeds and legume crops. Since seeds are considered to be the simplest and easiest materials for conservation in gene banks.
• Dry seeds are stored at low temperatures in seed banking techniques. Therefore, relative humidity, seed moisture content and temperature play an important role in determining the seed longevity.
• Advancement in ex-situ research shows that origin may be a key factor in determining their shelf life. In addition, seed longevity is also affected by endospermic or non-endospermic nature of seed and intra-specific variation.
• Seed longevity in seed banks is ensured by high quality seeds during initial stage. Sometimes, postharvest treatment of seeds can badly affect the initial seed quality and ultimately leads to genetic drift and erosion. It has also been found that conventional cold storage methods have several constraints like costs, and dependence on electric power sources.
• Seed moisture content (SMC) and temperature are independent factors. Moreover, SMC plays a vital role in long term conservation as compared to temperature. With a decrease in moisture content, seed longevity increases.
• Some studies also demonstrated that if seed drying is carried beyond critical moisture content, then no supplementary benefit will be provided to shelf life. However, it will lead to the acceleration of seed aging rates.
• If the storage temperature is lowered, then the optimum SMC level gets elevated. This suggests that over-drying of seeds can be dangerous.
• Some plants have recalcitrant nature; therefore they cannot be conserved in the form of seeds. Such type of plants are clonally propagated and traditionally conserved as live plants in field gene banks.
• However, field gene banks present some real and logical challenges like requirement of larger areas, expensiveness and vulnerability to pests and diseases.
• In- vitro slow-growth conservation methods provide backup to field collections.
• Cryopreservation in liquid nitrogen at −196°C is also a promising option for ex-situ conservation since it arrests mitotic and metabolic activities.
• Differential Scanning Calorimetry, biochemical and histo-cytological analyses led to the development of those cryo-protocols that were helpful for the conservation of approximately 200 plant species e. g: banana, coffee, and citrus
• Researchers are analyzing that the cryopreservation methods provide long term security and cost effective conservation of plant genetic resources (orthodox seeds).
• DNA material is the most requested material in gene banks and its demand is increasing for molecular studies. It was suggested that DNA storage facility should be established as a backup for traditional ex-situ conservation. However, fewer efforts have been made for the collection and conservation of DNA as a genetic resource.Although, some efforts have been made for the establishment of DNA banks for endangered animals and few plant species.
• Regeneration is a critical step and great challenge for gene bank management. This is because the probability of genetic erosion is highest during this step. Attributes that play key role in the preservation of genetic variability in gene banks is the sample size and the effective population size. Allelic frequency will change if the sample size is too small. It is an important aspect to understand that how various conservation methods like seed banks, field banks and cryopreservation affect the genetic makeup and lead to a reduction in effective population size.

Gene banks: The term gene bank is used for some specific purposes like pollen bank, semen bank or blood bank. The term gene bank is related to the conservation of plant genetic resources (PGR) under ex-situ conservation. The ex-situ conservation of cultivated and wild plant species and their wild relatives can be carried out by several institutions, modes and methods. Ex-situ conservation can be done in

• Field gene banks
• Seed/gene banks
• Botanical gardens
• Cryo-banks
• Herbaria
• DNA banks
• Seed museums
• Tissue culture banks

A gene bank is a genetic resource management programme co-ordinated by nodal agency and other active partners. In India, plant genetic resources management comes under the umbrella of Indian Council of Agricultural Research and Department of Agricultural Research and Education. It includes National Bureau of Plant Genetic Resources, National Active Germ-plasm sites at ICAR institutes and State Agricultural Universities. In India, National Bureau of Plant Genetic Resources (New Delhi) was established as National Gene Bank in 1983. The major gene banks throughout the world are present in China, USA, India, Russia, Germany, Japan, and Republic of Korea, Canada, Brazil, Italy and Ethiopia.

4.2. Ex-situ holdings in gene banks: Germ-plasm of 2.7 million crops has been conserved via ex-situ conservation. It includes accessions of:

• 1.3 million cereals
• 3,70,000 food legumes
• 2,20,000 forage grasses and legumes 1,38,000 vegetables
• 74,000 clones of fruit crops

Community gene banks: Sometimes, certain farming communities collaborate with non-governmental organizations for conserving their prevailing cultivars and landraces. This process is accomplished by medium term storage facilities. These medium term storage facilities are of two types: innovative and pre-fabricated. Out of these, latter is known as community gene banks. However, the innovative storage facilities can also be used for conservation purpose. This type of conservation is relevant for sustainable and dynamic use.

In-situ on farm conservation:

In-situ conservation method involves the conservation of plant genetic resources in a natural-undisturbed mode. It maintains diverse populations of traditional farming practices in a conventional-undisturbed mode. The in-situ on-farm conservation technique is the maintenance of natural plant populations within their agro-ecosystem for which they have been adapted originally.

The in-situ approach is commonly followed for

• Natural plant species Forest trees
• Wild species
• Progenitors of crop plants

The on farm conservation is applicable for the conservation of

• Semi domesticated/semi wild species
• Wild relatives/weeds of crops
• Landraces of crops and traditional cultivars
• Wild populations of cultivated plants

It has been estimated that 1.5 billion farmers are involved in in-situ on farm conservation throughout the world. In-situ conservation allows the dynamic and continued adaptation of plants to their natural environment in contrast to ex-situ conservation. In India, protected areas constitute 4.2% of total land area. Major bio-geographical zones of India include 496 wildlife sanctuaries and 89 national parks. They cover an area of 1, 83, 000 square kilometers. These areas help to conserve the biodiversity within their natural habitat.

First effort for in-situ conservation of agrobiodiversity was made in 1990s by the establishment of Citrus gene sanctuary in Nokrek biosphere reserve, Meghalaya. The research data and basic information regarding this project was provided by ICAR to Ministry of Environment, Forests and Climate Change (MoEFCC). MoEFCC is the nodal agency that looks into those matters that are related with the biodiversity. The same project was further taken up by Man and Biosphere Reserve (MAB) programme of United Nations.

Throughout the world, there are 18 hotspots and amongst these 2 are present in India. The buffer zones that are rich in agro biodiversity need to be applied in in-situ approaches for the conservation of genetic resources. However, the handling of conservation sites requires great research, large scale efforts, and increased awareness. Certain activities have been initiated by public and non-governmental organizations for on farm conservation of biodiversity. Some projects have been initiated in collaboration for the ‘on farm’ conservation of rice germ-plasm in tribal areas of Chhattisgarh. Collaborative studies have also been undertaken in fertile plains of northern region where rice-wheat system of cultivation is prevalent. Moreover, national plant genetic resources management system will provide technical suggestions to non-governmental organizations regarding ‘on-farm’ conservation practices.

With the advancement in technology, modern tools and methodologies have been developed so as to help the farmers in maintaining the genetic diversity of the crops growing in their fields.

5. Registration of biodiversity at local level

The Biodiversity Act, 2002 has the provision for the conservation and sustainable use of biodiversity at local level. For this purpose, Biodiversity Management Committee should be constituted by every local body. The major function of this committee (BMC) is to prepare biodiversity register after consulting local people. The register should contain detailed information regarding the availability of local biological resources, their usage and traditional knowledge associated with them. The biodiversity registers are maintained and validated by BMC.

6. Community recognition and awards

Contribution of farmers and farming communities have been recognized under ‘The Protection of Plant varieties and Farmer’s Rights act, 2001 (PPV&FR Act). Seventeen agrobiodiversity hot-spots in India have been demarcated for observing the contributions of farmers and farming communities in those areas where insitu on-farm conservation practice is still going on. Agrobiodiversity hot spots are shown in table 1:

Table 1 shows various agrobiodiversity zones in India and areas covered under them.

6.  Base and Active collection ex-situ collections are of two types: a) base collection b) active collection

These collections are held at every genetic resource centre.

a)   Base collection: The set of accessions that resembles closely to the original population in terms of genetic diversity is known as base collection. The accessions are preserved under long term storage conditions for maintaining the integrity. However, seeds in the base collection are not distributed directly to the farmers. Rather than, base collection acts as back up for an active collection of germ-plasm. The International standards were established in 1985 for long term storage. The standards were established by International Board of Plant Genetic resources.

Standards for ex-situ conservation require:

Sub-zero temperature

Seed moisture content (3%-7%)

Generally, 3%-7% seed moisture content with cooler temperatures is generally preferred. However, there are certain cases where seed moisture content needs to be raised. For e.g., seed breakage during handling.

b)   Active collection: The set of accessions that are available for immediate distribution and multiplication is known as active collection. The storage period of such types of accessions ranges from short term to medium term storage. The working collection of breeders is also stored for short-medium term. The accessions of active collections should be kept in such conditions so that the viability of accessions doesn’t go below 65% for 10-20 years. The desired temperature range where the accessions are kept is 0°C-10°C. It depends upon the nature of the species that have to be stored, prevailing environment and cost factors.

In India, 0.9 million accessions have been estimated for ex-situ collections i.e, active and base collection.

7. Indian National Gene bank

National Gene bank in India was established in 1983. At that time, it was holding capacity of 30,000 seed accessions. The seed accessions were held in two compartments for medium term storage at 4 °C and 10°C. Indian national gene bank ranks third amongst the world’s largest gene banks. The first and second ranks are attained by China and USA, respectively. Generally, gene banks are known to store orthodox seeds. However, they can also store non-orthodox seeds. The seeds are cryo-conserved in liquid nitrogen at -196 °C. Furthermore, the difficult, endangered and high quality tissues can be stored in in-vitro tissue culture bank of Indian National gene bank at sub-culture intervals of 4-24 months and temperature range of 5°C-25°C. If we talk about the holding capacity of Indian national gene bank, then it can hold 1 million seed samples, 25,000 tissue cultures other than propagules and quarter-million cryo-conserved materials. National gene bank also includes field gene banks for vines, trees, tuber crops and vegetatively propagated roots. Field gene banks are located in different agro-climatic zones of the country. Field gene banks hold the accessions of more than 5,000 trees and vines. 19,800 herbarium specimen, 2,822 seed voucher specimen and 564 economic products are available in National Herbarium of Cultivated Plants, National Bureau of Plant genetic Resources, and New Delhi, India.

8. National Active Germ-plasm sites

Around 57 National Active Germ-plasm sites have been linked to National Bureau of Plant Genetic Resources, New Delhi. These sites are responsible for the organization of active germ-plasm of horticultural and field crops. These sites are also responsible for the exchange of genetic resources amongst the interested users in the country.

9. Guidelines for sending seed samples for conservation

The following guidelines must be observed while sending seed samples for conservation:

a)  The seeds should be physiologically mature.

b)  Seeds should be free from insects, pests, weeds and diseases

c)  Seeds should not be undersized and discolored.

d) Seeds should be properly labeled and packed to avoid any sort of damage or integrity loss during the transit.

e) No chemical treatment should be given to the seeds prior to their dispatch.

f) Immediate after seed harvesting, they should be sent to gene banks.

g) Sufficient number of the seeds should be sent to the gene banks so that the accessions maintain the genetic diversity of the original population.

10. Indian scenario

The Director of NBPGR, New Delhi is the authorizing person to permit for the import of genetically modified organisms and germ-plasm for research purpose. However, the permission is subjected to approval by Review Committee on Genetic Manipulation (DBT), under the Environment Protection Act, 1986. The geographical Indications Act, 1996, has a provision for the protection and registration of those plant genetic resources that are peculiar for a geographical area. Agenda 21 has been declared as an action plan to be adopted at local, regional, national and international level for addressing the impacts of anthropogenic activities on biodiversity/agrobiodiversity. This agenda was adopted on June 1992 in a United Nation conference on Environment and Development held at Rio de Janerio, Brazil. It gave special importance to the development of some strategies for agrobiodiversity conservation and sustainable use of plant genetic resources. Global plan of action provided framework for the conservation and sustainable use of plant genetic resources for Food and Agriculture.

References

• http://www.bmel.de/SharedDocs/Downloads/EN/Publications/AgriculturalBiodiversity.pdf__blob=publicationFile.
• http://www.gbif.pt/sites/default/files/05_Agrotraining_Into%20AGB%20info%20for%20crop%20breeding.pdf.
• http://www.fao.org/docrep/007/y5609e/y5609e01.htm.
• https://www.eolss.net/sample-chapters/C17/E6-58-07-09.pdf.
• https://uc.socioambiental.org/en/agrobiodiversidade/what-is-agrobiodiversity
• https://en.wikipedia.org/wiki/Agricultural_biodiversity