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Chapter 16 Family Brassicaceae

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Family Brassicaceae

Botany

Brassicaceae is a very important family with over

1,800 species from more than 100 genera worldwide including many important vegetable, field, and oil crops (Table 16.1). Members of this family are also sometimes referred to by their archaic family name Cruciferae or are called crucifers for short (Nieuwhof, 1969; Rubatzky and Yamaguchi,

1997).

Plant and Flower Characteristics

The word Cruciferae means cross in Latin. The family was so named originally because of the characteristic cross-shaped flowers shared by all members of this family. Close examination reveals that each floret has four opposed flower petals that form a square cross (Fig. 16.1). Flower petals vary widely in color among species and may be white, cream, pink, or purple (Nieuwhof, 1969).

The flowers are bisexual with one pistil, and four long and two short stamens on each flower for a total of six. A superior ovary develops into a long fruit pod called a silique, 4.5–10 cm (2–4 in) in length, with a thin, translucent inner membrane, the replum, that separates the two chambers of the pod, and to which the seeds are attached (Fig. 16.2;

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Chapter 3 Vegetable Seeds and Crop Establishment

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Vegetable Seeds and Crop

Establishment

Introduction

Most vegetable crops are grown from seeds and not vegetatively propagated. A seed can be defined as

“an immature plant in an arrested state” produced through sexual reproduction. If a plant produces seeds that germinate “true-to-type” and grow rapidly, it is cheaper, more efficient, and usually faster to propagate the crop by seed. True-to-type simply means that the plant that results from a seed has the same traits and appearance as the plant that produced the seed.

Vegetables that do not grow true-to-type from seed or that are difficult to propagate from seed such as potato, sweetpotato, or globe artichoke are vegetatively propagated. Vegetative propagation is a form of asexual reproduction of a plant where the stems, leaves, and roots, or other tissue not involved in reproduction are rooted. With vegetative propagation, the new plant is a clone that is genetically identical to the parent.

Seeds produced through tissue culture are sometimes called synthetic seeds. Synthetic seed can be defined as the artificial encapsulation of somatic embryos, shoot buds, aggregates of cells, or any tissues that have the ability to form a plant (Fujii et al., 1987). Synthetic seeds have been produced commercially but make up a small percentage of the commercial vegetable seeds sold in the world.

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Chapter 10 Family Cucurbitaceae

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Family Cucurbitaceae

Origin and History

The cucurbits are largely tropical in origin with different genera originating in Africa, tropical

America, and Southeast Asia. Commercial cucurbits are primarily herbaceous annuals that produce distinctive tendril-bearing vines and are commonly grown in temperate regions with long growing seasons. Some are adapted to humid conditions while others are found in arid regions. Most are frostintolerant although some species are more tolerant of low temperature than others.

Taxonomy

The Cucurbitaceae family is well defined but taxonomically isolated from other plant families. The family Cucurbitaceae consists of about 120 genera and more than 800 species. Two subfamilies,

Zanonioideae and Cucurbitoideae, are well characterized: the former by small, striate pollen grains and the latter by styles united into a single column. The food plants all fall within the subfamily Cucurbitoideae and belong to two tribes: the Cucurbiteae and Sicyoideae (Maynard and Maynard, 2000).

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Chapter 5 Irrigation of Vegetable Crops

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Irrigation of Vegetable Crops

Introduction

Irrigation may be defined as the science of applying water to the land or soil. Irrigation has many diverse uses, including the growing of agricultural crops, maintenance of landscapes, revegetation of disturbed soils in dry areas and during periods of inadequate rainfall. Additionally, irrigation also may provide frost protection for vegetable crops (Snyder and Melo-Abreu, 2005). In contrast, production that relies only on direct rainfall is referred to as rain-fed or dryland vegetable farming. Successful vegetable production in many regions is dependent upon farmers having sufficient water for irrigation. Water scarcity is a critical constraint to farming in many parts of the world.

Arid regions frequently suffer from physical water scarcity. Physical water scarcity is where there is insufficient water to meet all demands, including those needed for ecosystems to function effectively.

Symptoms of physical water scarcity include environmental degradation and declining groundwater.

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Chapter 6 Mulches

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Mulches

Introduction and History

In this chapter, we will discuss the use of mulches in vegetable production. Irrigation was discussed in

Chapter 5, although there is overlap with this chapter.

Plastic mulches were first used experimentally for vegetable production in the early 1950s (Lamont,

2004a). By the 1960s, plastic mulches were widely used because growers quickly recognized that they were affordable, easy to install, provided effective weed control, and increased early harvest conserved moisture.

Early mulches were primarily black or clear. Black mulches were popular because they provided weed control and heated the soil to accelerate early season production of warm-season vegetables (see Fig. 6.2). Plastic mulch has been shown to benefit the production of many crops, but the cucurbits, pepper, tomato, and eggplant seem to show the greatest response. Approximately

6,500 km2 (2,500 miles2) of polyethylene mulch are used for crop production in the world today.

Plasticulture is defined as “a system for growing vegetable crops where significant benefit is obtained from using products derived from synthetic polymers” (Lamont, 1993). Typical plasticulture production consists of raised beds covered with plastic mulch, drip irrigation, delivery of chemicals through the drip irrigation (fertigation/chemigation), and preplant soil fumigation under the plastic mulch. Claimed benefits of the plasticulture system compared to conventional bare-soil production include: earlier production; higher yields per acre; cleaner, higher-quality product; more efficient use of water and fertilizer; reduced leaching of mineral nutrients; less soil erosion; fewer disease problems; fewer weed problems; better management of some insects; reduced soil compaction; less root pruning; and maximum efficiency through double- or triple-cropping (Lamont, 2004a).

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