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9: Pathogenesis of Alternaria Species: Physiological, Biochemical and Molecular Characterization

CABI PDF

9 

Pathogenesis of Alternaria Species:

Physiological, Biochemical and Molecular

Characterization

P.D. Meena,1* Gohar Taj2 and C. Chattopadhyay3

ICAR-Directorate of Rapeseed-Mustard Research, Bharatpur; 2Molecular Biology &

Genetic Engineering, G.B. Pant University of Agriculture & Technology, Pantnagar;

3

ICAR-National Centre on Integrated Pest Management,

Pusa Campus, New Delhi, India

1

Introduction

Alternaria blight or black leaf, and silique spot is an exceptionally serious disease of oilseed brassica crops worldwide. It is mainly induced by Alternaria brassicae (Berk) Sacc., A. brassicicola (Schwein) Wiltshire, and is a n

­ ecrotrophic pathogen that can infect every plant part in  every plant growth stage. The symptoms emerge on all aerial parts of the plant, generally resulting in serious damages to yield and quality of the seed. The disease starts as minute dark-brown to light black pustules on the older leaves that spread rapidly on to the above foliar parts of the plant by producing typical centred bands and a yellow circle of discoloration in and surrounding the lesions.

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9 Integrating Nutrition into Agricultural and Rural Development Policies: The Brazilian Experience of Building an Innovative Food and Nutrition Security Approach

Thompson, B., Amoroso, L. CABI PDF

9

Integrating Nutrition into Agricultural and Rural Development Policies: The Brazilian

Experience of Building an Innovative Food and Nutrition Security Approach

Luciene Burlandy,1* Cecilia Rocha2 and Renato Maluf 3

Universidade Federal Fluminense, National Council of Food and Nutrition Security

(CONSEA), Rio de Janeiro, Brazil; 2Ryerson University, Toronto, Ontario, Canada;

3

Universidade Federal Rural do Rio de Janeiro and National Council of Food and Nutrition Security, Rio de Janeiro, Brazil

1

Summary

Established in 2006, Brazil’s National System of Food and Nutrition Security is made up of representatives of civil society organizations and different governmental sectors. Innovative programmes have emerged as a consequence of this institutional framework. Effective connections made at programme design and implementation level have generated concrete results, such as the convergence of different programmes geared to the poorest groups. This chapter analyses different assessments of the Family

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12: Abiotic Stresses with Emphasis on Brassica juncea

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12 

Abiotic Stresses with Emphasis on Brassica juncea

D.K. Sharma,1* D. Kumar2 and P.C. Sharma1

ICAR-Central Soil Salinity Research Institute, Karnal, Haryana, India;

2

ICAR-Central Arid Zone Research Institute, Jodhpur, Rajasthan, India

1

Introduction

Agricultural productivity is affected by a number of abiotic stresses. These may include deficit or excess water availability, flash floods, high salt levels in soil as well as in irrigation water and extreme temperatures.

In addition, mineral deficiency or toxicity is frequently encountered by plants in agricultural systems. In many cases, different abiotic stresses challenge plants in combination. For example, high temperatures and scarcity of water are commonly encountered in periods of drought and can be exacerbated by mineral toxicities that constrain root growth. Further, plants are also exposed to salinity, drought and frost-like conditions in combination in some of the cases. Higher plants have evolved multiple, interconnected strategies that enable them to survive abiotic stresses. However, these strategies are not well developed in most agricultural crops. Across a range of cropping systems around the world, abiotic stresses are estimated to reduce yields to less than half of that possible under ideal growing conditions. Traditional approaches to breeding crop plants with improved stress tolerance have so far met with limited success, in part because of the difficulty of breeding for

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7 Soil Carbon Dynamics and Nutrient Cycling

Banwart, S.A., Noellemeyer, E., Milne, E. CABI PDF

7 

Soil Carbon Dynamics and

Nutrient Cycling

David Powlson*, Zucong Cai and Philippe Lemanceau

Abstract

The quantity of organic carbon in soil and the quantity and type of organic inputs have profound impacts on the dynamics of nutrients. Soil organic matter itself represents a large reservoir of nutrients that are released gradually through the action of soil fauna and microorganisms: this is especially important for the supply of N, P and S to plants, whether agricultural crops or natural vegetation. Organic matter also modifies the behaviour and availability of nutrients through a range of mechanisms including increasing the cation exchange capacity of soil, thus leading to greater retention of positively charged nutrient ions such as Ca, Mg, K, Fe, Zn and many micronutrients. Carboxyl groups in organic matter, and in root exudates or microbial metabolites, form complexes with various metal ions, usually increasing their availability to plants. In some cases, the formation of stable complexes has a detoxifying effect, for example by making Al and Cu less available to plants or microorganisms. Organic matter influences soil physical conditions greatly, especially through the formation or stabilization of aggregates and pores; this indirectly influences the availability of water and dissolved nutrients to plant roots. Organic matter and organic inputs are the source of energy for heterotrophic soil organisms, variations in organic carbon content and composition, impacting biome size, diversity and activities. These complex interactions between organic carbon and the soil biome require additional research to be fully understood. The implications for nutrient dynamics differ between nutrient-rich situations such as agricultural topsoils and nutrient-poor environments such as subsoils or boreal forests. In agricultural soils, excessive inputs of organic matter in manures can lead to pollution problems associated with losses of N and P.

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3 Setting a Baseline: Case Studies

McVay L.A. CABI PDF

Case Studies

41

Introduction

In undertaking to choose which interviews would be most appropriate to examine as case studies, it became readily apparent that two case studies of unlike natures would best provide a demonstration of the richness of the data present in all twenty-two of the transcripts. Therefore, the two women chosen as case studies were at opposite ends of the leadership spectrum, and provided an in-depth view of two quite dissimilar narratives of leadership development. Alice, twenty-eight, and at the beginning of her career, had been brought up in an environment that offered access to nearly every educational and social opportunity available to children in rural Northern Ireland. Alternatively, Doreen (twenty-four years Alice’s senior, with decades of work experience) faced challenges that had kept her from participating in most of those same activities. In addition to their age and social differences, Alice’s leadership development process had been shaped considerably by External Factors and Doreen’s vastly more by Internal Factors.11 The slight variations in data presentation between Alice and Doreen’s case studies demonstrate the flexibility necessitated by incorporating such dissimilar voices, and the value of a methodology that creates space for such flexibility.

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