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Questions and Answers
What type of plant is Teff categorized as?
What type of plant is Teff categorized as?
Which region is recognized as the original area of domestication for Teff?
Which region is recognized as the original area of domestication for Teff?
What part of the Teff plant is primarily utilized for food?
What part of the Teff plant is primarily utilized for food?
Which plant family does Eragrostis tef belong to?
Which plant family does Eragrostis tef belong to?
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In which environment is Teff most widely cultivated today?
In which environment is Teff most widely cultivated today?
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Which plant family does Arugula (Eruca vesicaria) belong to?
Which plant family does Arugula (Eruca vesicaria) belong to?
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What type of plant is Arugula categorized as?
What type of plant is Arugula categorized as?
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What part of the Arugula plant is primarily used for food?
What part of the Arugula plant is primarily used for food?
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How is Arugula typically prepared for consumption?
How is Arugula typically prepared for consumption?
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What is the native distribution of Arugula (Eruca vesicaria)?
What is the native distribution of Arugula (Eruca vesicaria)?
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What was the primary focus of early plant classification systems?
What was the primary focus of early plant classification systems?
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What was a significant problem with common names in plant classification?
What was a significant problem with common names in plant classification?
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Which system of nomenclature replaced polynomial nomenclature due to its cumbersome nature?
Which system of nomenclature replaced polynomial nomenclature due to its cumbersome nature?
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Who was responsible for the introduction of the binomial system in plant classification?
Who was responsible for the introduction of the binomial system in plant classification?
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What does the species name in the binomial system consist of?
What does the species name in the binomial system consist of?
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What characteristic of Genotype 2 would lead to its increased representation in future generations?
What characteristic of Genotype 2 would lead to its increased representation in future generations?
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Which of the following is NOT a result of the selection pressures applied during early agricultural practices?
Which of the following is NOT a result of the selection pressures applied during early agricultural practices?
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What factor ensures that at least some seeds will mature when environmental conditions are favorable?
What factor ensures that at least some seeds will mature when environmental conditions are favorable?
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What was an unconscious outcome of the planting-harvesting link in early agricultural development?
What was an unconscious outcome of the planting-harvesting link in early agricultural development?
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Which characteristic is favored by selection against clonal axillary shoots in wild grasses?
Which characteristic is favored by selection against clonal axillary shoots in wild grasses?
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What primary hypothesis did Edgar Anderson propose regarding plant domestication?
What primary hypothesis did Edgar Anderson propose regarding plant domestication?
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What was one of the consequences of population pressures as suggested by Binford and Flannery?
What was one of the consequences of population pressures as suggested by Binford and Flannery?
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Which location is believed to be one of the principal centers of agricultural origin?
Which location is believed to be one of the principal centers of agricultural origin?
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How did the climatic changes influence the development of agriculture according to various hypotheses?
How did the climatic changes influence the development of agriculture according to various hypotheses?
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What was a significant archaeological finding at the site of Jarmo in present-day Iraq?
What was a significant archaeological finding at the site of Jarmo in present-day Iraq?
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Which statement correctly describes the final chromosome arrangement of bread wheat?
Which statement correctly describes the final chromosome arrangement of bread wheat?
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What is the primary reason cereal grains have a long shelf life?
What is the primary reason cereal grains have a long shelf life?
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How did the development of modern bread wheat involve hybridization?
How did the development of modern bread wheat involve hybridization?
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In the context of cereal crops, what does the term 'caryopsis' refer to?
In the context of cereal crops, what does the term 'caryopsis' refer to?
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What agricultural innovation is linked to the accidental fermentation of wheat gruel?
What agricultural innovation is linked to the accidental fermentation of wheat gruel?
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Which statement correctly describes the protein content of wheat compared to corn?
Which statement correctly describes the protein content of wheat compared to corn?
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What structural feature of corn aids in its hybridization?
What structural feature of corn aids in its hybridization?
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What is a consequence of wheat's gluten composition during baking?
What is a consequence of wheat's gluten composition during baking?
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How has modern corn cultivation adapted from its original conditions?
How has modern corn cultivation adapted from its original conditions?
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Which statement best describes the role of corn in modern agriculture?
Which statement best describes the role of corn in modern agriculture?
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What is the primary reproductive challenge faced by triploid apple cultivars?
What is the primary reproductive challenge faced by triploid apple cultivars?
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Which of the following statements accurately describes domestication in the context of the tomato?
Which of the following statements accurately describes domestication in the context of the tomato?
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What genetic characteristic is common among older apple varieties compared to most modern cultivars?
What genetic characteristic is common among older apple varieties compared to most modern cultivars?
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Why is capsaicin concentration significant in capsicum peppers?
Why is capsaicin concentration significant in capsicum peppers?
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What is the primary characteristic that differentiates simple fruits from aggregate fruits?
What is the primary characteristic that differentiates simple fruits from aggregate fruits?
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What was a notable outcome of modern plant breeding programs for tomatoes?
What was a notable outcome of modern plant breeding programs for tomatoes?
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Which type of ovary position defines an inferior ovary in flowering plants?
Which type of ovary position defines an inferior ovary in flowering plants?
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What function do the stamen serve in flowering plants?
What function do the stamen serve in flowering plants?
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Which of the following statements correctly describes the composition of the pericarp?
Which of the following statements correctly describes the composition of the pericarp?
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What distinguishes fleshy fruits from dry fruits at maturity?
What distinguishes fleshy fruits from dry fruits at maturity?
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Which characteristic distinguishes legumes from most other plant families regarding nitrogen?
Which characteristic distinguishes legumes from most other plant families regarding nitrogen?
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What is one primary reason legumes are significant in diets where meat is limited?
What is one primary reason legumes are significant in diets where meat is limited?
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What is a common type of economic legume notably consumed in a dried state?
What is a common type of economic legume notably consumed in a dried state?
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Which statement correctly describes the composition of legume fruits?
Which statement correctly describes the composition of legume fruits?
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In addition to protein, what nutrient is primarily supplied by legumes to improve soil quality?
In addition to protein, what nutrient is primarily supplied by legumes to improve soil quality?
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Study Notes
Botanical Information
- Eragrostis tef belongs to the Poaceae family (grass family).
- It is an herbaceous annual plant.
- Its native distribution is Ethiopia and Eritrea.
History as a Food Plant
- This plant was first domesticated in the Ethiopian Highlands.
- It is widely grown in Ethiopia, Eritrea, and other parts of East Africa.
Utilization
- The seeds of the plant are used as a food source.
- The seeds are typically harvested and processed into flour.
- The flour is used to make injera, a flatbread that is a staple food in Ethiopia and Eritrea.
- The flour is also used to make other foods like porridge, bread, and pasta.
Botanical Information
- Arugula belongs to the Brassicaceae family.
- Arugula is an herbaceous annual.
- Arugula is native to the Mediterranean region and parts of Asia.
Utilization
- The leaves of the Arugula plant are used as a food.
- Arugula leaves can be eaten raw or cooked.
History of Plant Classification
- Theophrastus created the first plant classification system around 2300 years ago.
- He identified key characteristics to distinguish natural plant groups, recognizing families like Pea, Grass, Sunflower, and Mustard.
- The Age of Herbals (1470-1670) expanded upon these early works, following the invention of the printing press.
- Herbal manuscripts listed illustrations of plants and their medicinal properties, using common names.
- Common names posed problems: the same name could refer to different species, or one species could have multiple names, and different languages often used different common names.
- A standard, Latin-based system of nomenclature was developed to address communication problems with common names.
- Initially, a polynomial nomenclature was used, where a generic designation was followed by a descriptive Latin "phrase name."
- This system was cumbersome, up to a paragraph in length and later simplified by Carl Linnaeus.
- Linnaeus' binomial system, introduced in Species Plantarum (1753), is still used today.
- In this system, the species name consists of a generic name and a species epithet, such as Picea glauca for white spruce.
- The system follows rules from the International Code of Botanical Nomenclature, including:
- Capitalization of the first letter of the generic name, but not the species epithet.
- Italicization (or underlining) of the binomial name.
- Use of authority designations: e.g., Picea glauca (Mo-ench) Voss.
Plant Species
- A biological species is defined as a group of individuals that can interbreed with one another, but not with individuals of another species.
- However, this definition may not apply well to plants due to:
- Spatially separated populations of the same species may not easily interbreed.
- Some plant species may form fertile hybrids when crossed.
- Some species never interbreed with one another.
- Plant taxonomists therefore use morphological form to classify and describe species.
- Even morphological form is problematic because:
- Large changes in morphology may result from simple genetic changes.
- Plants are known for plasticity, with their morphology depending on environmental conditions, such as light levels or touch.
- Evolution is constantly altering morphological form.
Evolutionary Relationships of Flowering Plants
- Morphologically based classifications are known as phenetic classification systems.
- This approach emphasizes conservative characters - characters that do not vary with environmental conditions.
- Floral characters are generally favored over more variable characteristics like leaf size and shape.
- Examples of floral characters used in phenetic classification include:
- Inflorescence Type
- Flower Structure
- Fruit and Seed Types
- Charles Darwin's Origin of Species (1859) increased interest in a phylogenetic approach to classification, which emphasizes evolutionary relationships.
- Implementation of a phylogenetic classification requires:
- Information on the ancestral relationships of flowering plants.
- Deciding which characters are "primitive" (evolved early), and which are "advanced" (evolved more recently).
- In the 19th century, two competing theories regarding flowering plant evolution were proposed:
- Engler's theory: The earliest evolved flowers were small, structurally simple, and wind-pollinated.
- Hooker's theory: The earliest evolved flowers were large with numerous floral parts.
- Hooker's system is accepted today, with between 300 and 350 flowering plant families recognized.
Flowering Plants: Monocots and Eudicots
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Traditional plant classification recognizes two major flowering plant (Angiosperm) groups: the monocotyledons (or monocots) and the eudicotyledons (or eudicots).
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This division is based on the number of cotyledons ("seed leaves") found in the seed:
- Monocots have a single cotyledon.
- Eudicots have two cotyledons.
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These groups can be distinguished by several additional morphological features (although there are exceptions):
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Monocots:
- Plant Form: Herbaceous, never woody.
- Floral Parts: Three or multiples (3,6,9...).
- Leaves: Linear, sheathing the base, parallel-veined.
- Root System: Primary root is short-lived, fibrous root system developed.
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Eudicots:
- Plant Form: Herbaceous or woody.
- Floral Parts: Four, five or multiples (4,8,10...).
- Leaves: Broad, not sheathing, net veined.
- Root System: Primary root often persists, forming a taproot.
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Monocots:
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Recent genetic investigations have revealed that the division into monocot and eudicot groups is too simplistic from an evolutionary perspective.
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A third group, known as the magnoliid Angiosperms, evolved prior to the divergence of the monocots and eudicots.
The Hypothesis of Agricultural Development
- Several theories explain agricultural development, including:
- Less Optimal Areas: As populations grew, people moved to less favorable areas, forcing them to domesticate plants for year-round food. This theory was proposed for Southeast Asia.
- Weed Precursor: Weeds, through hybridization in disturbed habitats, led to genetic variations, resulting in useful food plants. Edgar Anderson supported this theory.
- Applied Botanists: Early gatherers were skilled botanists who deliberately cultivated plants based on needs. This theory suggests a simple transition from intensive gathering to cultivation due to population pressures or climate change.
Centers of Agricultural Origin
- Three main centers for the origin of agriculture are:
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Asia Minor (Near East): Semi-arid regions of Iran, Iraq, and eastern Turkey.
- Jarmo (Iraq): Evidence suggests wild grains were collected 10,000 years ago, with wheat becoming the primary cereal crop by 8,750 years ago.
- Tigris-Euphrates Valleys: Human populations moved into these valleys around 7,000 years ago, leveraging reliable water and food sources, leading to advanced urban civilizations by 6,000 years ago.
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Mesoamerica (Central America):
- Aztec (Mexico): Developed intensive irrigation agriculture.
- Mayan: Selected specific corn and bean cultivars.
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Andes Region (South America):
- Inca: Domesticated potatoes and developed irrigation systems.
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Asia Minor (Near East): Semi-arid regions of Iran, Iraq, and eastern Turkey.
Selection Pressures on Plants
- Plant Characteristics: Result from genetic evolution through natural selection.
- Cultivation Impact: Domestication drastically altered plant characteristics, although early agriculture didn't involve deliberate selection.
- Passive Selection: The planting-harvesting link led to rapid passive selection of beneficial cultivars.
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Wild vs. Cultivated Plant Characteristics:
- Seed Production: Wild plants often have prolific seed producers with extended maturation periods, ensuring survival under varying conditions.
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Cultivated Plants:
- Simultaneous Seed Maturation: Cultivated plants favored those with simultaneous seed maturation, ensuring harvest efficiency.
- Uniform Seed Maturation: Selection against tillering (clonal axillary shoots) for uniform seed maturation.
- Seed Appendage Loss: Selection for non-edible appendages that shatter before harvest.
- Germination Inhibitor Loss: Selection for simultaneous germination.
- Increased Florets: Selection for more florets to produce more seeds.
- Day-Length Sensitivity Loss: Selection for crops that are not dependent on day length for seed production.
- Loss of Shattering: Selection for seeds that remain attached to the plant during harvest.
- Increased Food Reserves: Selection for seeds with higher carbohydrate content and lower protein content for faster seedling growth.
Geographic Origin and Spread of Plants
- Limited Global Distribution: Most food crops had limited global distributions.
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Introduction Impact: New crops led to significant changes in agriculture and human diets.
- Examples: Potatoes (South America to Europe), Tomatoes and Chili Peppers (South America to Europe and Asia), Sugar Cane (Southeast Asia to the Caribbean)
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Europe:
- Roman Influence: Introduction of Mediterranean crops like peas, oats, rye, and herbs to Northern Europe.
- Arabic Colonization: Introduction of rice, sugar cane, sorghum, and citrus fruits to Spain.
- European Conquest of Americas: Corn (maize), potatoes, and other crops were introduced to Europe.
- Eastern Asia Exploration: Introduction of Asian crops like rhubarb, almond, apricot, peach, coffee, black pepper, and others to Europe.
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Asia:
- Indigenous Crops: Rice is a major indigenous crop in Asia.
- American Introductions: Corn (maize), papaya, pineapple, potato, sweet potato, tapioca (cassava), and chili pepper were introduced from the Americas.
- African Introduction: Coffee was introduced from North-East Africa.
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Africa:
- Indigenous Crops: Coffee, sorghum, millet, yam, cowpeas, watermelon, sesame, and palm oil
- Asian Introductions: Coconut, rice, and bananas.
- Near East Introductions: Mango and eggplant.
- American Introductions: Cassava, sweet potatoes, corn (maize), and beans.
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Americas:
- Central and South America: Indigenous crops like corn, cassava, potato, sweet potato, peanuts, tomato, chili peppers, and beans.
- North America: Few native crop plants.
- Colonial Introductions: Sugar cane, bananas, rice, citrus fruits, breadfruit, and coffee were introduced by Spanish and English colonists.
The Green Revolution
- Crop Breeding Focus: Emphasis on high yield, at the expense of disease and pest resistance.
- High-Yield Crop Needs: Higher costs, increased need for fertilizers, water (possibly requiring irrigation), herbicides, pesticides, and mechanized harvesting.
- Vulnerability: More susceptible to weather anomalies like wet or dry seasons, hail, and windstorms.
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Green Revolution Impacts:
- Technological Farming: Promoted technological farming practices.
- Developing Nation Challenges: Benefiting developed nations with large-scale farms but often detrimental to developing countries due to high costs.
- Climate Challenges: Crops bred for temperate regions often do not thrive in tropical and subtropical climates and soils.
Plant Monocultures
- Plant Monoculture: Extensive plantations of a single genotype.
- Susceptibility: Highly susceptible to pest and pathogen outbreaks due to lack of genetic resistance.
- Irish Potato Famine: The entire Irish potato crop was derived from a single plant, making it highly vulnerable to the potato blight leading to widespread famine.
Genetic Engineering
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Genetically Engineered (GE) Crops: Crops with genetic information added from other organisms for pest, pathogen, and herbicide resistance.
- Examples: Canola, soybean, and corn.
- Consumer Resistance: European countries often have bans or strict regulations on GE crops, with growing opposition in North America.
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Concerns:
- Environmental Impacts: Escape into natural habitats, hybridization with native plants, potential harm to ecosystems.
- Safety and Health: Concerns about the unnatural nature of GE crops.
- Accessibility: Expensive GE seeds make them less accessible to farmers in developing countries.
Genetic Diversity
- Crop Development Dependency: New crops and medicinal drugs rely on genetic diversity.
- Loss of Diversity: Older, less productive plant varieties have disappeared with the development of new ones.
- Potential Value of Older Varieties: Older varieties may contain valuable genetic information for modern breeding programs.
- Natural Ecosystem Loss: Loss of tropical rainforests and other ecosystems reduces genetic diversity, harming global biodiversity.
Cereal Crops
- Cereal grains are a concentrated food source, high in carbohydrates and low in water content
- Cereal grains have been vital to agriculture worldwide
- Cereal grains belong to the Grass (Poaceae) family
- Cereal grains are technically dry indehiscent fruit, also known as a caryopsis
Bread Wheat
- Bread wheat arose in Asia Minor, the modern form is a hybrid complex from Triticum, Agropyron, and Aegilops
- Bread wheat is a hexaploid, with 42 chromosomes, six times the base chromosome number
- Bread wheat contains gluten proteins needed for traditional bread-making
- Wheat gruel most likely led to leavened bread and alcoholic beverages
Corn
- Maize, or corn, is native to Central America and has been cultivated for at least 7000 years
- It was critical to the development of the Mayan, Aztec, and Inca civilizations
- Corn is unique with its separate male (tassels) and female (ears) flowers
- Corn is low in protein, especially lysine and vitamins compared to other cereal grains
- It lacks gluten proteins, allowing for the creation of tortillas
- Modern corn is a mutated derivative of the wild grass, teosinte
Rice
- Rice cultivation began in China and Southeast Asia
- Rice prefers a hot, humid climate with high rainfall
- Paddy rice requires constant submergence in water
- Upland rice does not need submergence and grows in areas with saturated soils
- Rice requires nutrient-rich soil, especially nitrogen, and is labor-intensive
- Rice can be categorized into long-grained (indica) and short-grained (sativa)
- Rice requires limited processing to consume
- The bran and germ of rice are used as animal fodder
- Polished white rice is high in starch and low in protein
- Processing removes thiamine leading to beriberi
Oats
- Oats are mainly used for cattle feed and fodder
- Oats are high in protein and is grown in moist, temperate areas
- Oats do not contain gluten proteins
Rye
- Rye originated from S. montanum, a weed mimicking wheat and barley
- Rye is grown in cool climates and tolerates nutrient-poor soils
- Rye flour is used for bread, especially in Eastern Europe and Russia
- Rye flour produces a dense, dark and bitter bread
- Rye can be infected with fungal ergot, causing severe symptoms in humans
- Ergot contains Ergotamine, LSD, and alkaloid compounds
Sorghum
- Sorghum is an annual grass native to Africa, grown in Asia, India, Africa, and the United States
- Sorghum is drought-resistant and thrives in warm to hot temperatures
- In the U.S., it is primarily used as fodder and forage for cattle and pigs
- Sorghum is high in carbohydrates and protein
Barley
- Barley may be the first domesticated cereal
- Barley cultivation began around 10,000 years ago
- Barley is grown in cool, temperate climates
- Barley tolerates salinity and can be grown on marginal soils
- Barley is used as animal fodder
- Malt barley is processed specifically for beer and whiskey
Millets
- "Millet" refers to several cereal crop species
- Millets are tolerant of drought and poor soil conditions
- Millets are widely cultivated in India, Pakistan, and parts of Africa
Botanically, Fruits
- Fruits are mature, ripened ovaries of flowering plants that contain seeds.
- This definition includes a wide range of structures, like legumes (e.g., pea pods, beans) and nuts (e.g., hazelnut), which differ from the typical grocery store definition.
- Seeds develop from fertilized ovules inside the ovary.
- As fruit matures the ovary wall becomes the pericarp, which encloses the seeds.
- The pericarp consists of three layers: exocarp (outer), mesocarp (middle), and endocarp (inner).
- Flowers contain both male (stamen) and female (carpel) parts for efficient pollination.
Fruit Classification
- Fruits are classified based on three main criteria:
- Superior or Inferior Ovary: Superior ovaries are located on top of the flower, while inferior ovaries are located below the flower.
- Dry or Fleshy: Fleshy fruits are watery and juicy (e.g., apple, oranges), while dry fruits are not watery (e.g., nuts, grains).
- Simple, Aggregate, or Multiple: Simple fruits develop from one ovary on a single flower. Aggregate fruits are the fusion of multiple ovaries on a single flower, while multiple fruits involve multiple ovaries from multiple flowers.
Rose (Rosaceae) Family
- A large eudicot family with showy, insect-pollinated flowers.
- Rose fruits are often fleshy, large and showy, and dispersed by animals.
- This family is economically important, with many species grown commercially.
- Most apple and pear varieties originated in Eastern and Central Asia with some pears also native to Europe.
- All apple varieties are derived from Malus domestica.
- The apple fruit develops from a five-parted inferior ovary.
- Older apple varieties are diploid and produce seeds, while modern cultivars are mostly triploid and sterile.
Tomato (Solanaceae) Family
- A large eudicot family with global distribution.
- This family includes domesticated species like tobacco, potato, and medicinal plants.
- Important edible Solanaceous fruits include:
- Tomato (Lycopersicon esculentum): Native to Central America and domesticated by the Mayans. Initially viewed with suspicion in Europe due to poisonous relatives. Modern cultivars are larger and less pungent than their wild ancestor.
- Sweet and Capsicum Peppers (Capsicum annuum and C. frutescens): Originated in Central America. "Hotness" is due to capsaicin found in the placental tissue.
- Guarana (Paullinia Cupana): Fruit contains caffeine and is used for a popular South American beverage.
Mulberry (Moraceae) Family
- Economically important members produce multiple fruits.
- White and Black Mulberries (Morus alba and M. nigra): Minor temperate crops.
- Figs (Ficus carica): Subtropical tree, commercially significant.
- Breadfruit and Jackfruit: Important carbohydrate sources in the tropics.
Other Temperate Fruits
- Grape (Vitis vinifera): Native to the Eastern Mediterranean, mostly used for wine production. Some are eaten fresh or dried into raisins.
- Pomegranate (Punica granatum): Native to the Middle East, multi-seeded fruit with a bright red pulp called the aril.
- Kiwi (Actinidia deliciosa): Indigenous to China, first commercialized in New Zealand.
- Olive (Olea europea): Native to the Mediterranean, important source of cooking oil. Olives are processed with caustic soda to remove bitterness.
Other Tropical Fruits
- Many subtropical and tropical fruits are wild-harvested or grown commercially on a small scale.
- Coconut: Highly versatile, historically providing clothing, building materials, and drinking vessels.
Commercially Important Dicots
- Durian (Durio zibethinus): Native to Western Malaysia, very large fruit known for its pungent aroma and complex taste.
- Avocado (Persea americana): Indigenous to Central America, rich in oil and nutritious.
- Mango (Mangifera indica): Native to India and Malaysia, cultivated for over 4,000 years. Ripened fruit is a sweet dessert, while unripe fruit is used for cooking.
- Papaya (Carica papaya): Indigenous to Central America, fruit is popular in tropical countries.
Nuts
- Botanically, a nut is a dry, one-seeded indehiscent fruit with a hard, woody pericarp (e.g., Hazelnut).
- Commonly, the term refers to edible, high-protein seeds from certain plants.
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Temperate:
- Walnut (Juglans regia): Native to Southeast Europe and Western Asia. The fruit is a drupe, and the "nut" sold commercially is the woody endocarp that encloses the edible seed.
- Pecan (Carya illinoinensis): Native to the southern United States, the "nut" is the woody endocarp containing a single seed.
- Almond (Prunus dulcis): Native to Western Asia, the "nut" is the seed of a drupe with a bitter, inedible mesocarp.
- Hazelnut (Corylus avellana): Native to Eurasia, a "true nut" botanically.
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Tropical:
- Cashew (Anacardium occidentale): Native to Northeast Brazil. Both the cashew fruit (apple) and seed (nut) are edible.
- Pistachio (Pistacia vera): Indigenous to Central Asia, related to the cashew.
- Brazil Nut (Bertholletia excelsa): Native to Amazonian rainforest, fruit capsules contain 10-25 edible seeds.
- Macadamia Nut (Macadamia integrifolia): Native to South-east Australia, cultivated commercially in Hawaii.
Legumes: The Fabaceae Family
- Legumes, or pulses, belong to the Fabaceae (Legume or Pea) family.
- The family includes both herbaceous plants like peas and beans, and woody trees like acacia and tamarind.
- Legumes are found worldwide.
Legumes: Fruit Structure
- The fruit of a legume is called a legume.
- It is a single-chambered pod with seeds attached along one edge, like a pea pod.
Legumes: Key Nutritional Features
- Dried legume seeds are high in protein, containing up to 25-30%.
- They are comparable to red meat in protein content.
- Legumes are a crucial protein source, especially where meat is scarce or expensive.
- They are essential for vegetarians and those who avoid eating meat, as they contain all essential amino acids.
Legumes: Key Agricultural Features
- Legumes are vital high-protein forage for domestic animals.
- Legumes produce root nodules that contain nitrogen-fixing bacteria (genus Rhizobium).
- These nitrogen-fixing bacteria convert atmospheric nitrogen (N
2) into nitrate (NO3) usable by plants. - This mutualistic relationship benefits both the legumes and the bacteria.
- The plants provide sugars to the bacteria through starch from photosynthesis.
- In return, the plants receive essential nitrogen for growth.
- Nitrogen is incorporated into plant tissues, especially seeds, as protein.
- Decomposing legume parts release some nitrate into the soil, naturally improving nutrient-impoverished soils.
Economically Important Legumes
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Common or Kidney Bean (Phaseolus vulgaris):
- Native to Central and South America.
- Several cultivars are grown, including green beans and dried kidney beans.
- Dried kidney beans contain about 20% protein.
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Pea (Pisum sativum):
- An ancient legume crop, cultivated for at least 7,000 years.
- Native to the Mediterranean, Middle East, and northeastern Africa.
- Many pea cultivars have been developed.
- Seeds can be dried (about 25% protein) or eaten fresh.
- "Sugar peas" have pods eaten fresh.
- Peas were a key protein source in Medieval Europe.
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Soybean (Glycine max):
- Likely derived from wild soya (Glycine soya).
- Native to China, Japan, and Korea (East Asia).
- Cultivated for over 3,000 years in northeast China.
- Seeds are very high in protein (35-40% dry weight) and contain all essential amino acids.
- The world's most important legume crop, with over 100 million tons produced annually.
- Major producers are the United States, China, and Brazil.
- Soybeans require warm temperatures and a long growing season.
- Used for various purposes: fresh and dried beans, bean sprouts, edible oil products, industrial oils, Asian cooking products, processed protein products, food additives, livestock and pet food.
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Peanut or Groundnut (Arachis hypogaea):
- Native to Central and South America.
- First domesticated over 3,500 years ago.
- Classified as a "nut" but is a legume.
- 1-3 seeds per pod.
- Two main types: the prostrate Virginia type and the upright Spanish type.
- Over 30 million tons harvested annually.
- Major producers are India, China, Nigeria, and the United States.
- Unique feature: flower stalk elongates after pollination, pushing the maturing fruit into the soil, requiring loose, sandy soils.
- Most peanuts are processed into edible and industrial oils or used for animal feed.
- Typically roasted as a snack, processed into pastes and sauces (peanut butter, satay), added to stews and stir-fries.
Tropical Pulses: Important Global Food Source
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Lima bean (Phaseolus lunatus), large green beans
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Broad bean (Vicia faba) similar to lima beans
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Chickpea (Cicer arietinum):
- One of the oldest cultivated legumes.
- Used for hummus.
- Key in Mediterranean and Middle Eastern cuisine.
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Black gram of urd (Vigna mungo), black beans with a white line.
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Mung bean or green gram (V.radiata):
- similar to black gram but green instead with a white line.
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Black-eyed bean (V.unguiculata), white with black stripes.
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Asparagus or yard-long bean (V.unguiculata var.sesquipedalis),
- Viny, can climb up to 12 ft.
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Pigeon pea (Cajanus cajan):
- Hardy, can grow in any soil, tolerant to poor conditions.
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Lentil (Lens culinaris):
- An ancient crop from Southwest Asia.
- Widely grown on the Indian subcontinent to produce dahl, a lentil puree.
- Numerous drought-tolerant cultivars have been developed.
Other Important Legumes
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Carob (Ceratonia siliqua):
- Subtropical tree native to the Arabian Peninsula.
- Large pods known as St. John's Bread.
- Seeds rich in protein and sugar.
- Pods sold fresh for the edible "sweetmeat" around the seeds.
- Processed into a paste used as a chocolate substitute.
- Gum from the seeds is a stabilizer and thickener in food products like ice cream, salad dressing, processed meat, and other food products.
- Both the pod and seeds are edible.
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Tamarind (Tamarindus indica):
- Large tree native to India.
- Like carob, it has large pods.
- The sweet "meat" around the seeds is used in tropical cuisines.
- It is particularly important in tropical cuisines in India, Philippines, Middle East, and so on.
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Fenugreek (Trigonella foenum-graecum):
- Native to the Mediterranean and Southwest Asia.
- The seed has been used medicinally and as a food source since ancient times.
- An important crop in India, the Middle East, and Africa.
- Fenugreek seed is an important spice in curry dishes.
- Fresh leaves used as a vegetable in India.
- Dried leaves are an aromatic spice.
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Liquorice (Glycyrrhiza glabra):
- Native to the Mediterranean region and central Asia.
- Known to the ancient Greeks and Romans.
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Description
Explore the fascinating plant Eragrostis tef, an important herbaceous annual in the Poaceae family. Learn about its native origins in Ethiopia and Eritrea, its domestication as a food source, and its critical role in local cuisine, including the making of injera. This quiz provides insights into its utilization and significance in East African culture.
