Preface

Chapter 7 **Lessons from Common Bean on How Wild Relatives and**

Chapter 8 **Critical Aspects on the Use of Microsatellite Markers for**

**Authenticity of their Food Derivatives 131**

Chapter 9 **Wild Soybeans: An Opportunistic Resource for Soybean**

Chapter 10 **Genetic Variation of Landraces of Common Bean Varying for**

**Resources for Conservation and Breeding 179**

Enéas Ricardo Konzen and Siu Mui Tsai

**Seed Coat Glossiness and Disease Resistance: Valuable**

Andrés J. Cortés and Matthew W. Blair

Fabio Palumbo and Gianni Barcaccia

**Climate Change 115**

**VI** Contents

**Improvement 163**

**Landraces Can Make Tropical Crops More Resistant to**

**Assessing Genetic Identity of Crop Plant Varieties and**

Muhammad Amjad Nawaz, Seung Hwan Yang and Gyuhwa Chung

A cropped variety or cultivar is an intraspecific taxonomic entity characterized by a high level of homozygosis, especially for the genes that control the selected traits. Consequently, the individuals belonging to the same variety show homogeneous morphological and/or produc‐ tive traits. Nevertheless, some differences in genetically controlled biochemical traits may ex‐ ist within the same variety. These variations are defined as "biotypes." Different from varieties, landraces are natural populations put in cultivation, and as such, they are character‐ ized by a wide adaptability to various environments. Considering all the abiotic factors, the high probability of interpopulation crosses and their heterozygosis condition, from the genet‐ ic point of view, these populations result to be more than a mixture of different pure lines.

On the other hand, a landrace is intrinsically different, from the genetic point of view, and recognizable as a distinct entity, allowing to distinguish one landrace from another or from modern cultivars for the same crop. This differentiation is also on the basis of the great as‐ sortment of landrace names, linked to their origin, or specific morphological, chromatic and productive traits, or particular biological cycles, or many other reasons.

Landraces are generally less productive than commercial cultivars, but many authors agree they have played a fundamental role in the history of crops worldwide, in crop improve‐ ment and in agricultural production, and they have been in existence since the origins of agriculture itself.

In recent years, all over the world, the attention paid to local and traditional productions is growing, especially in the agro-food sector. Maybe, it is not only due to the impact of global‐ ization and the social and economic changes but also due to the increased consideration to health and nutritional aspects of food. Hence, for economic, social, historical and nutritional reasons, this trend has led to the rediscovery and reuse of landraces of many different crops, responding to requests for more and more demanding market.

This volume collects real examples of local crops and old landraces of different areas of the planet that testify the extreme importance of the relation existing among a land, the local productions, the historical traditions, the conservation of biodiversity, the health benefits, the environmental impact and the local economies, also including the significance to dedi‐ cate resources to scientific researches in local crops.

> **Oscar Grillo** Experimental Institute for Wheat, Italy

**Section 1**

**Rediscovery of Landraces as a Resource for the**

**Future**

**Rediscovery of Landraces as a Resource for the Future**

**Chapter 1**

**Provisional chapter**

**Landraces and Crop Genetic Improvement**

**Landraces and Crop Genetic Improvement**

DOI: 10.5772/intechopen.75944

Landraces are repository of gene pool that enrich biodiversity and maintain and stabilize ecosystem in a sustainable way to make it functional. Cultivation of traditional crops in different regions of the world, aside maintaining biodiversity in agriculture, also avails humanity of regulatory services such as nutrient cycling, carbon sequestration, control of soil erosion, reduction of greenhouse gas emission and control of hydrological processes. However, man through over-exploitation of some plant species with utter neglect to some other either deliberately or otherwise through modern agricultural systems that promote cultivation of a few high-input and high-yielding crop species caused disaffection to biodiversity with consequences of reduction in its regulatory services. In this chapter, different landraces of crops are examined, their usefulness in the maintenance of

genetic diversity is explored, and implications of their depletion are discussed. **Keywords:** genetic diversity, adaptation, conservation, heterogeneity, utilization

Landraces are defined as dynamic populations of a cultivated plant with a historical origin, distinct identity, often genetically diverse and locally adapted, and associated with a set of farmers' practices of seed selection and field management as well as with a farmers' knowledge base [1] . Sangam et al. [2] referred to plant landraces as heterogeneous local adaptations of domesticated species providing genetic resources that meet current and new challenges for farming in stressful environments. These local ecotypes can show variable phenology and low to moderate edible yield but are often highly nutritious. The main contributions of landraces to plant breeding have been traits for more efficient nutrient uptake and utilization, as well as useful genes

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Musibau A. Azeez, Amos O. Adubi and

Musibau A. Azeez, Amos O. Adubi and

http://dx.doi.org/10.5772/intechopen.75944

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

Felicia A. Durodola

Felicia A. Durodola

**Abstract**

**1. Introduction**

#### **Chapter 1 Provisional chapter**

#### **Landraces and Crop Genetic Improvement Landraces and Crop Genetic Improvement**

DOI: 10.5772/intechopen.75944

Musibau A. Azeez, Amos O. Adubi and Felicia A. Durodola Musibau A. Azeez, Amos O. Adubi and Felicia A. Durodola

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.75944

#### **Abstract**

Landraces are repository of gene pool that enrich biodiversity and maintain and stabilize ecosystem in a sustainable way to make it functional. Cultivation of traditional crops in different regions of the world, aside maintaining biodiversity in agriculture, also avails humanity of regulatory services such as nutrient cycling, carbon sequestration, control of soil erosion, reduction of greenhouse gas emission and control of hydrological processes. However, man through over-exploitation of some plant species with utter neglect to some other either deliberately or otherwise through modern agricultural systems that promote cultivation of a few high-input and high-yielding crop species caused disaffection to biodiversity with consequences of reduction in its regulatory services. In this chapter, different landraces of crops are examined, their usefulness in the maintenance of genetic diversity is explored, and implications of their depletion are discussed.

**Keywords:** genetic diversity, adaptation, conservation, heterogeneity, utilization

#### **1. Introduction**

Landraces are defined as dynamic populations of a cultivated plant with a historical origin, distinct identity, often genetically diverse and locally adapted, and associated with a set of farmers' practices of seed selection and field management as well as with a farmers' knowledge base [1] . Sangam et al. [2] referred to plant landraces as heterogeneous local adaptations of domesticated species providing genetic resources that meet current and new challenges for farming in stressful environments. These local ecotypes can show variable phenology and low to moderate edible yield but are often highly nutritious. The main contributions of landraces to plant breeding have been traits for more efficient nutrient uptake and utilization, as well as useful genes

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

for adaptation to stressful environments such as water stress, salinity and high temperatures. A systematic landrace evaluation may define patterns of diversity, which will facilitate identifying alleles for enhancing yield and abiotic stress adaptation, thus raising the productivity and stability of staple crops in vulnerable environments. It can also be defined as a traditional variety with a high capacity to tolerate biotic and abiotic stresses, resulting in highyield stability and an intermediate yield level under a low-input agricultural system [3]. A landrace differs from a variety that has been selectively improved by breeders for particular characteristics.

Hawkes [17] opined that landraces are associated with one specific geographical location, in contrast to cultivars which are bred remotely, trialed in several locations and subsequently cultivated in diverse locations. Therefore, landraces are closely associated with 'specific locations' and often will take the name of the location [11]. Examples of this are Kent Wild White Clover from the UK county of Kent and Tuxpenõ maize from the Tuxpan region in Mexico. However, migrations (seed flow) of established landraces from their region of origin to new regions have also occurred as local informal variety introductions. Zeven [3] proposed two types of landraces: **autochthonous** (landraces cultivated for more than a century in a specific region) and **allochthonous** (a landrace that is autochthonous in one region introduced into another region and becoming locally adapted). In that case, the examples of Kent Wild White Clover and Tuxpenõ maize are cultivated in regions other than where they originated. Kent Wild White Clover is grown in some hilly areas of Scotland and Tuxpenõ maize in several regions of Southern Mexico. A third type known as a 'Creole' landrace may be derived from an originally bred variety [18, 19], which then becomes an effective landrace following numerous repeated cycles of planting and farmer seed selection in a specific location. For instance, Square Head Master Wheat, identified as a cultivar in the National List of the UK, has been grown continuously since 1930 by the family of Paul Watkin (a farmer from Suffolk, UK) sav-

Landraces and Crop Genetic Improvement http://dx.doi.org/10.5772/intechopen.75944 5

Continuity and individual cultivation and discontinuity and collective cultivation are both significant. Individual farmers commonly lose and recover landraces as a result of their management of a dynamic portfolio of landraces [19] and seed replacement [20] and because of various stochastic events such as drought, floods, pests and diseases. Village or local community continuity may be maintained through farmer's seed exchange networks if cultivation is by more than one farmer. In fact, several papers have highlighted the relevance of seed exchange for the maintenance of landraces [20–22]. Such localized farmer exchange activities may help to define and ensure continuity of a landrace. However, the introduction of 'exotic' landraces to a locality is likely to adulterate the uniqueness and local adaptation of the local landraces. Therefore, many believe that the maintenance of an 'open' cultivation system, with routine local or more remote introductions of germplasm, is likely to be responsible for the

Landrace production is associated with 'no human selection' [11] and 'it was naturally developed' [23]; thus, landraces have been developed as a result of time and natural selection alone. Other authors suggest that human selection has occurred but in the form of unconscious selection, and others suggest that a certain degree of consciousness is involved in the selection process, 'without or with only little mass selection' [23], 'subject to some deliberate selection' [24], 'artificial selection (probably largely of an unconscious nature)' [17] and 'breeding or selection … either deliberately or not' [14]. Where conscious human selection has been recognized as being significant in landrace development, it has nevertheless been distinguished that is applied to modern cultivars [7, 12] with qualifications such as 'more resistant to pests and diseases, have more yield stability' [25],

ing seed each year.

maintenance of genetic diversity in landraces.

**3. Lack of formal genetic improvement**

Landraces are important genotypes for crop breeding owing to their high potential to adapt to specific environmental conditions and the large source of genetic variability that they provide [4]. Landraces are generally less productive than commercial cultivars, although in recent years, they have become important as sources of genetic variability in the search for genes for tolerance or resistance to biotic and abiotic factors of interest in agriculture [5]. The genetic diversity observed across landraces is the most important part of maize biodiversity, and local races represent an important fraction of the genetic variability exhibited by this genus. However, few agronomic and genetic data exist for such collections, and this scarcity has limited the use, management and conservation of this germplasm. In addition, a few improved genotypes with narrower genetic variability are quickly replacing maize landraces [6].

Zeven opined that landraces have played a fundamental role in the history of crops worldwide, in crop improvement and agricultural production, and they have been in existence since the origins of agriculture itself. During this time they have been subject to genetic modification through abiotic, biotic and human interactions. For centuries, crop landraces were the principal focus for agricultural production [7]. Farmers sowing, harvesting and saving a proportion of seed for subsequent sowing over millennia have enriched the genetic pool of crops by promoting intraspecific diversity [8]. This cycle remained current until the dawn of formal plant breeding and the generation of generally higher-yielding cultivars that subsequently replaced many traditional landraces [7, 9, 10].
