Preface

Chapter 7 **Ralstonia solanacearum: A Bacterial Disease and Its Biological Control by Essential Oils on Solanum tuberosum L. 125**

Rueda Puente

**VI** Contents

Cristina Ruiz Alvarado, Ramón Jaime Holguin Peña and Edgar Omar

Thousands of people die every year in many parts of the world due to hunger and malnutri‐ tion. It is necessary to increase crop production so that human beings can feed on a sufficient and balanced diet to sustain their existence on Earth. This can only be achieved by increasing the amount of yield obtained from each unit area of land, since it is not possible to further increase existing cultivating areas. In parallel with increasing population, agricultural areas are being used for other nonagricultural purposes (settlement, road, factory, etc.) or are shrinking rapidly due to erosion, salinization, acidification, intensive agriculture, and over‐ grazing.

The yield in agricultural production declines due to biotic and abiotic stress factors. Devel‐ oping a resistant or tolerant cultivar against stress factors is the main goal of plant breeding. It is possible to increase the production to a certain degree by using high-yielding cultivars, fertilizing and applying chemicals where necessary. Chemical methods are commonly used to combat biotic stressors (diseases and pests) that reduce crop production. However, herbi‐ cides and insecticides have been shown to cause the emergences of new diseases and pests. In addition, unconscious use of fertilizers and chemicals applied in plant production has negatively affected long-term ecological balance.

Potato (*Solanum tuberosum* L.), a very important crop, is the world's fourth largest food crop production following maize, wheat, and rice with approximately 390 million tons on 19 mil‐ lion ha. Potato is a staple crop in many diets worldwide, and the underground swollen tu‐ bers of the plant are a rich source of proteins, carbohydrates, minerals (K, Mn, Mg, Fe, Cu, and P), and vitamins (C, B1, B3, B6, K, folate, pantothenic acid). Global average potato yield, 12 tons/da, is below its yield potential because of biotic (diseases and pests) and abiotic (sal‐ inity, drought, high temperature, etc.) stress factors. That is why improvement of new culti‐ vars resistant to stress factors by conventional and biotechnological methods is extremely important. The most important factor in production increase is the use of healthy seed tu‐ bers along with using drought-, heat-, and salt-tolerant cultivars. On the other hand, protec‐ tion and storage of surplus crops, which are the most important stage in its marketability, are the main problems in potato. It is hoped that this book will help growers and researchers in solving problems in potato cultivation.

> **Prof. Dr. Mustafa Yildiz** Ankara University, Faculty of Agriculture Department of Field Crops Ankara, Turkey

**Section 1**

**Potato Breeding**

**Section 1**
