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ADDIS ABABA UNIVERSITY
SCHOOL OF GRADUATE STUDIES
Plant Biology and Biodiversity Management Programme Unit
Crop Diversity
Name. Zewde AchisoID. No. GSR/0865/05
June, 2013
Outline
Introduction
Crop Diversity and their Role in sustaining Food security
Diversity in major and minor crops in Ethiopia
Conservation Strategies to Maintain Crop Diversity
Why Diversity of Crop Matters?
Types of conservation In-situ conservation Ex-situ conservation
Benefits and Challenges of in-situ and ex-situ conservationValue of conserving crop diversity
IntroductionLife is all around us. From the microbes in our gut, the insects
crawling in our garden soil , the garden and wild variety of plants to the largest mammal on earth -the blue whales.
In other words, Biodiversity is the variability among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems and the ecological complexes of which they are part:
This includes diversity within species, between species and ecosystems.
It is both essential for our existence and intrinsically valuable in its own right.
Because it provides the fundamental building blocks for goods and services a healthy environment provides
Agro-biodiversity is subpart of biodiversity that includes all the components of biological diversity of relevance to food and agriculture, and
Crop diversity refers to the biological diversity found in crops used for food and agriculture.
It is sometimes referred to as `plant genetic resources for food and agriculture.
This diversified crops and other plant species help our ecosystem function;
Basically to fix nitrogen, sequester carbon dioxide and stabilize soils,
Directly or indirectly providing us with medicines, building materials, lubricants, resins, waxes, perfumes, dyes, fibers and, of course, food.
Cont---
cont--- Diversity of crop both in landraces and in their wild relatives provide important resources for
Food security, Environmental sustainability and Economic stability.
Generally crops have values, like social, cultural, economic, and ecological and based on this values we will try to focus on the following points
What crop diversity is, Diversity in major and minor crops, The role of crop diversity, Conservation strategies to maintain their diversity, Their benefits and challenges and Value of conserving crop diversity
Crop diversity embraces the great variety within and between crops and their wild relatives.
These varieties evolved over thousands of years in a dynamic interaction between nature and farmers’ careful selection and breeding
About 7,000 plant species have been used for human consumption,
but only four crops (wheat, maize, rice and potato) provide
one-half of the total world food production and Only 15 crops contribute two-thirds of the world population
Crop Diversity and their Role in sustaining Food security
wheat maize rice potato
Eragrostis tef
Pisum sativum
Vitis viniferaRice
Oryza sativa
Cont---
Diversity in major and minor crops in Ethiopia
Ethiopia is one of the richest genetic resource centers in the world. This is principally attributed to the diverse farming systems, socio-economics, cultures and agro-ecologies. Crop plants such as
Coffee (Coffea arabica), Safflower (Carthamus tinctorius), Tef (Eragrostis tef), Noug (Guizotia abyssinica), Anchote (Coccinia abyssinica), Enset (Ensete ventricosum), are known to have originated in Ethiopia.
The four of the world’s widely grown food crops wheat, barley, sorghum and peas;
The three world’s most important industrial crops linseed, castor and cotton;
The most important cash crop (coffee) in the world; The number of food crops of regional and local importance
Tef, Noug, Ethiopian mustard, Enset, Finger millet, Cowpea, Lentil, and
Number of forage species of world importance Clovers, Medics, Oats
Generally Ethiopia is center of major and minor crops origin and diversification
Why Diversity of Crop Matters? Diversity is necessary to furnish new genes for crop improvement
cont---
Conservation is crucial because the extent of diversity shows declining by the advancement of genetically uniform improved cultivars.The two forms of diversity are diversity among crops and within cropWider diversity is needed to meet
Human nutritional needsDependence on too few varieties is
Dangerous because disease or Pests can spread rapidly in genetically uniform crop
Black rot on carrot (left), nematode injury to carrots (middle), carrot weevil injury (right)
Most widely accepted scientific methods of biodiversity conservations are:
(I)In situ methods & (ii) Ex situ methods
Conservation Strategies to Maintain Crop Diversity
Benefits and Challenges of in-situ and ex-situ conservationBoth conservation methods have their own benefits and drawbacks
The merits of in situ conservation includes Avoidance of storage problems associated
With field gene banks and Recalcitrant seeds, Allowance of evolution and Enhancement to continue through exposure to pest and Diseases and other environmental factors, Indirect benefits, like ecosystem support and the like
But ex-situ conservation has advantages of Rescue of threatened germplasm, Requires limited space and, conserves adequate representative Ease of accessibility and exchange of germplasm, Ease for documentation, no exposure to pests, disease and other hazards and more cost effective
However, both methods have their own drawbacks
Value of conserving crop diversityAttaching the value of crop diversity is a complex task, But describing the kinds of benefits associated with these resources is easierThe simplest benefit arises from the direct use of crop diversity
Producing food and fiber or Evolving new varieties of crops and Livestock.
Benefits of crop varieties can be measured in Increased output, Higher quality, and Better resistance to pests, diseases, stress
Crop genetic resources are the basis from which all crop production stems and Having large amount single crop can not satisfy the necessity of human being ( see the above figure)But habitat loss, the dominance of scientific breed over farmer-developed varieties, and genetic uniformity are all threats to continued diversity