Onions and Other Vegetable Alliums

Synopsis

This fully revised, expanded and updated edition of the successful text, Onions and Other Vegetable Alliums, relates the production and utilization of these familiar and important vegetable crops to the many aspects of plant science underpinning their production and storage technologies. Chapters cover species and crop types, plant structure, genetics and breeding, physiology of growth and development as well as pests and diseases, production agronomy, storage after harvest and the biochemistry of flavour, storage carbohydrates and colour and how this relates to nutritional and health benefits. From this wide perspective it is possible to see many examples where underlying scientific knowledge illuminates, explains and can improve agronomic practice. The reader will get an insight into how molecular methods are revolutionizing the study of taxonomy, genetics, pathology and physiology and how these methods are being applied in the breeding of improved crops.

Summary

Chapter 1: Botany and Taxonomy of Vegetable Alliums

* Introduces the Allium genus and its classification.
* Describes the morphological characteristics of different Allium species, including bulbs, leaves, stems, flowers, and seeds.

Real Example:
Red onion: A variety of Allium cepa characterized by a reddish-purple bulb and sharp, pungent flavor.

Chapter 2: Origin, Distribution, and Economic Importance

* Explores the origins and geographical distribution of vegetable alliums.
* Discusses the economic importance of alliums, including their use as food, flavorings, and medicinal herbs.

Real Example:
Garlic (Allium sativum): A widely cultivated species used in cooking and traditional medicine for centuries.

Chapter 3: Cultivation of Vegetable Alliums

* Provides guidelines for growing vegetable alliums, including site selection, soil preparation, planting, irrigation, fertilization, and pest control.
* Discusses the specific cultural requirements of different Allium species.

Real Example:
Onion set production: The technique of growing onions from small, dried bulbs rather than seeds, resulting in larger, more uniform bulbs.

Chapter 4: Postharvest Handling and Storage

* Examines the techniques used to prepare and store vegetable alliums after harvest.
* Covers practices such as curing, cleaning, grading, and packaging.
* Discusses factors affecting postharvest quality and shelf life.

Real Example:
Onion curing: A process of drying and ventilating onions to improve their storage life and reduce spoilage.

Chapter 5: Composition and Nutritional Value

* Analyzes the chemical composition of vegetable alliums.
* Presents data on their nutrient content, including vitamins, minerals, fiber, and antioxidants.

Real Example:
Leeks (Allium ampeloprasum): A good source of vitamins K and C, as well as several minerals, including potassium, manganese, and copper.

Chapter 6: Medicinal Properties and Health Benefits

* Reviews the scientific evidence on the medicinal properties of vegetable alliums.
* Discusses their potential role in reducing the risk of chronic diseases, such as heart disease, cancer, and diabetes.

Real Example:
Allicin: A sulfur-containing compound found in garlic that exhibits antimicrobial, anti-inflammatory, and blood-thinning effects.

Chapter 7: Genetic Diversity and Improvement

* Explores the genetic diversity within the Allium genus.
* Outlines strategies for genetic improvement, including hybridization, selection, and molecular breeding techniques.

Real Example:
Onion breeding for resistance to diseases such as downy mildew and pink root rot.

Chapter 8: Future Prospects

* Discusses emerging trends and challenges in the cultivation, processing, and marketing of vegetable alliums.
* Highlights areas for future research and development.

Real Example:
The use of protected cultivation techniques, such as greenhouses and tunnels, to extend the growing season and improve yield.