1. ADDIS ABABA UNIVERSITY
SCHOOL OF GRADUATE STUDIES
Plant Biology and Biodiversity Management
Programme Unit
Crop Diversity
Name. Zewde
Achiso
ID. No.
GSR/0865/05
June,
2013

2. 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 conservation
Value of conserving crop diversity

3. Introduction
Life 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

4. 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---

5. 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

6.  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

7. Eragrostis tef
Pisum sativum
Vitis vinifera
Rice
Oryza sativa

8. Cont---

9. 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.

10. 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---

11. 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 crop
Wider diversity is needed to meet
Human nutritional needs
Dependence 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)

12. Most widely accepted scientific methods of biodiversity
conservations are:
(I)In situ methods & (ii) Ex situ methods
Conservation Strategies to Maintain Crop
Diversity

13. Benefits and Challenges of in-situ and ex-situ conservation
Both 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

14. Value of conserving crop diversity
Attaching the value of crop diversity is a complex task,
But describing the kinds of benefits associated with these
resources is easier
The 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