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