Classification of field crops

AGR-401 Field Crop Production-I

AGRON Lectures

• Introduction
• Classification of field crops
  • Botanical classification
    • Binomial system
    • Crop families
  • Agronomic Classification
    • Cereals
    • Pulses
    • Oilseeds
    • Fiber Crops
    • Forage Crops
    • Sugar Crops
    • Tubers
    • Vegetables
    • Condiments
    • Medicinal plants
    • Narcotic plants
• Glossary

Introduction

It is well established that there are over \(600\) cultivated plant species, with about \(100-200\) species playing a significant role in global trade. However, the most important economic crops are represented by just \(15\) plant species. As a result, these crop species must be categorized or clustered in a useful manner to encourage scientific correspondence, distribution, and retrieval, as well as to foster the survival and enhancement of specific plants. The description of these species is critical for the following reasons:

• To familiarize oneself with crops.
• To comprehend the soil and water requirements of various crops.
• To read about seed adaptability.
• To be aware of crop growing habits.
• To comprehend the climatic requirements of various crops.
• To consider the crop plant’s economic production and how it is used.
• To determine the crop’s growing season
• To have a greater understanding of the real conditions that must be fulfilled in order for the planting to take place.

Classification of field crops

The following are the various stand points at which field crops are grown:

• Botanical classification
• Agronomic classification
• Special purpose classification
• According to life span
• According to root depth
• According to growth habit
• According to CO₂ fixation
• According to mode of pollination

Botanical classification

Plant parts and flower arrangement are classified botanically based on their resemblance. This is the most important classification tool since it decides how closely related the plants are. Field crops are part of the plant kingdom’s spermatophyte, or seed plant, which involves seeds-reproducing species. Under this division, typical crop plants are classified as Angiosperm, which produces seeds with coats (covered seed). The “angiosperm” are then classified into two groups: monocotyledons and dicotyledons. Monocotyledons include all grasses, namely cereals and sugarcane. The legumes and other plants except the grasses are classified as dicotyledons. Each of these two classes is still further divided into orders, families, genera, species and varieties.

For example, maize crop (corn) which is monocotyledons belongs to the order herbaceous; family Gramineae; genus Zea; species mays; variety; Gauher.

Binomial system

The genus and species names are given to each crop plant. The genus name begins with a capital letter, while the species name begins with a small letter. A letter or abbreviation is used to denote the name of the man who first gave the accepted name. Wheat, for example, is classified scientifically as Triticum aestivum L. The letter L. denotes that it was named after Swedish botanist Carl Linnaeus.

A crop may often be called by another scientist. As a result, the crop name is preceded by the first scientist’s initial (between bracts) and then the second scientist’s initial, as in soybean. Glycine max (L) Merr., is the scientific name for this crop. To be differentiated from other words, the scientific name must be italicised or underlined.

Crop families

The families of the most important field crops can be summarized as follows, based on botanical classification:

1. Monocotyledons

   • Gramineae

     Poaceae or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns and pasture. It includes; wheat, barley, rice, maize, oat, sugarcane, sorghum, rye grass, and sudan grass.

   • Liliaceae

     The lily family, Liliaceae, consists of about \(15\) genera and \(610\) species of flowering plants within the order Liliales. They are monocotyledonous, perennial, herbaceous, often bulbous geophytes. Plants in this family have evolved with a fair amount of morphological diversity despite genetic similarity. It includes onion and garlic.

2. Dicotyledons

   • Leguminosae

     The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, are a large and economically important family of flowering plants. It includes trees, shrubs, and perennial or annual herbaceous plants, which are easily recognized by their fruit and their compound, stipulate leaves. Field bean, lupine, chickpea, lentil, fenugreek, Egyptian clover, alfalfa, soybean, peanut, grass pea, caster bean, red clover, and white clover are all members of the Leguminosae family.

   • Malvaceae

     Malvaceae, or the mallows, is a family of flowering plants estimated to contain \(244\) genera with \(4225\) known species. Well-known members of economic importance include okra, cotton, cacao and durian. There are also some genera containing familiar ornamentals, such as Alcea, Malva and Lavatera, as well as Tilia.

   • Linaceae

     Linaceae is a family of flowering plants. The family is cosmopolitan, and includes about 250 species in 14 genera, classified into two subfamilies: the Linoideae and Hugonioideae. Leaves of the Linaceae are always simple; arrangement varies from alternate to opposite or whorled. It includes flax (Linum usitatissimum).

   • Solanaceae (nightshade)

     Solanaceae, the nightshade, or potato, family of flowering plants, with \(102\) genera and nearly \(2,500\) species, many of considerable economic importance as food and drug plants. Among the most important of those are potato (Solanum tuberosum); eggplant (S. melongena); tomato (S. lycopersicum); peppers (various Capsicum species) and tobacco (Nicotiana tabacum and N. rustica).

   • Pedaliaceae

     Pedaliaceae, the pedalium family or sesame family, is a flowering plant classified in the order Scrophulariales in the Cronquist system and Lamiales in the Angiosperm Phylogeny Group system. The sesame is a small family of \(14\) genera and \(70\) species.

   • Compositae

     A very large family of flowering plants, Compositae (or Asteraceae) or sunflower family, comprising about \(1,100\) genera and more than \(20,000\) species, including the daisy, lettuce, and marigold. The composite plants are eudicots and are considered to be the most highly evolved plants.It includes sunflower, and safflower.

Agronomic Classification

The agronomic function of the major cultivated crops can be categorized. The distinguishable classes of crops can be determined on this basis.

Cereals

A cereal is any grass that has been cultivated (grown) for the edible components of its grain (botanically, a kind of fruit known as a caryopsis), which are made up of endosperm, germ, and bran. The term may also apply to the grain produced as a result of the process (specifically cereal grain). Important cereals are wheat, rice, maize, oat, barley, rye, millet and sorghum.

Pulses

The word pulses refers to crops that are harvested only as dried grains, as opposed to other vegetable crops that are harvested while still fresh. Pulses are nutritious, stable, and simple to cook. Growing pulses also helps to foster sustainable agriculture by reducing greenhouse gas emissions, improving soil quality, and using less water than other crops. Common pulses include chickpeas (kabuli, desi), lentils (mash, masoor), dry peas, beans (mung, lobia).

Oilseeds

any of a number of seeds from cultivated crops yielding oil, e.g. rape, peanut, or cotton. Whole oilseeds contain high concentrations of energy and moderate concentrations of protein and fiber. Because of this, oilseeds are frequently used as an energy source in the diets of lactating dairy cows. Common examples of oilseeds are rapeseed and mustard, sunflower, safflower, groundnut, sesame, soybean, linseed and caster seeds.

Fiber Crops

Fiber crops are plants that are deliberately grown for the production of fiber for textile (clothes), cordage (e.g., ropes), and filling (e.g., stuffing upholstery and mattresses). Cotton, jute, kenaf, industrial hemp, sun hemp, and flax are among the well-known fiber crops.

Forage Crops

Forage crops are crops grown specifically to be grazed by livestock or conserved as hay or silage. Forage crops assist in achieving production targets for attributes such as growth or weight gain and to make up seasonal short falls between feed demand and supply. The cereal crops when harvested as whole and used for animal feed are called fodder crops. For example barseem, shaftal and clovers.

Sugar Crops

Sugar crops are those crops which are grown for the production of sugar. The examples include sugarcane, sugar beet and sweet sorghum.

Tubers

Tubers are enlarged structures in some plant species used as storage organs for nutrients. They are used for the plant’s perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing season, and as a means of asexual reproduction. The examples of tubers include beets, carrots, potatoes, yams and turnips.

Vegetables

Vegetables are parts of plants that are consumed by humans or other animals as food. The original meaning is still commonly used and is applied to plants collectively to refer to all edible plant matter, including the flowers, fruits, stems, leaves, roots, and seeds. Some common vegetables are spinach, cucumber, gourds, eggplant, okra and tomato.

Condiments

Condiment crops produce edible materials used in small amounts to impart flavor to food. These include culinary herbs, spices, and plants from which flavorful chemicals can be extracted.

Medicinal plants

Medicinal plants, also called medicinal herbs, have been discovered and used in traditional medicine practices since prehistoric times. Plants synthesise hundreds of chemical compounds for functions including defence against insects, fungi, diseases, and herbivorous mammals. Some common examples of medicinal plants are turmeric, garlic, mint, chillies and ginger.

Narcotic plants

plants containing substances that cause unusual excitation and subsequent depression of the central nervous system. Many narcotic plants contain substances that have medicinal properties and are used primarily as pain relievers. Alkaloids are the principal active constituents of narcotic plants. The common examples of narcotic crops include poppy, opium, tea, coffee and pepper mint.

Glossary

Angiosperm

a plant of a large group that comprises those that have flowers and produce seeds enclosed within a carpel, including herbaceous plants, shrubs, grasses, and most trees.

Cereal

also called grain, any grass (family Poaceae) yielding starchy seeds suitable for food.

Clover

Clover or trefoil are common names for plants of the genus Trifolium, consisting of about 300 species of flowering plants in the legume or pea family.

Crop

is a group of plants grown as a community in a specific locality and, for a specific purpose.

Dicotyledons

a flowering plant with an embryo that bears two cotyledons (seed leaves). Dicotyledons constitute the larger of the two great divisions of flowering plants, and typically have broad stalked leaves with net-like veins. Legumes (pea, beans, lentils, peanuts), daisies, mint, lettuce, tomato and oak are examples of dicots.

Monocotyledons

a flowering plant with an embryo that bears a single cotyledon (seed leaf). Monocotyledons constitute the smaller of the two great divisions of flowering plants, and typically have elongated stalkless leaves with parallel veins. Grains (wheat, corn, rice, millet), sugarcane, banana, palm, ginger, onions, bamboo and grass are examples of plants that are monocots.

Spermatophyte

a plant of a large division that bear seeds, including the gymnosperms and angiosperms.