Module 2: Title: Crop Description: Definition, taxonomy is a work in progress, Importance of classifying the crops, Ways of classification of crops, Classification of crops, classifying and naming is a science governed by international rules, operational classification systems, and Agronomic Use MODULE OBJECTIVES This module is aimed at: (i) introducing students to the crop taxonomy (ii) Understanding the basic concept in Agricultural (iii) Understanding the importance of classification and how plants are classified (iv) Identifying and classifying some selected tropical plant (v) Knowing the relevance of taxonomy to Agriculture.

LEARNING OUTCOMES At the end of the module, students should be able to define crop taxonomy, outline briefly the scope of Agricultural taxonomy, classify crop, and know the importance of classifying crop.

Plant taxonomy is the science of identifying, classifying and naming plants. This task is accomplished by using data from a variety of sources, including morphological, anatomical, ultrastructural, physiological, phytochemical, cytological and evolutionary. Plants are grouped according to relationships based on characteristics from these sources. The plays a significant role in because it is a very stable organ across different environments. NOTE: Plant taxonomy is the science of identifying, naming and classifying plants

TAXONOMY IS A WORK IN PROGRESS What is the basis for assigning plants to certain categories? There are seven (7) general taxonomic groups in botanical or scientific classification of plants. is the most inclusive group; species is the least inclusive. Each group is called a taxon (plural is taxa). KINGDOM------Most inclusive group DIVISION CLASS ORDER FAMILY Genus Species------least inclusive group The Binomial system of nomenclature is based on these two groups: Genus and Species Carolus Linnaeus developed a two-part name, called the binomial nomenclature, for plants. This consists of the genus and the species names. Taxonomy is a work in progress. As new information becomes available, scientists revise the existing names to old names (e.g. the grass family used to be Graminae but is now called Poaceae. There are five major groups (kingdoms) of all : Plantae, Animalia, Protoctista, Fungi and Monera (Table 2-2). Plants belong to the kingdom Plantae (plant kingdom). Importance of classifying the crops To get acquainted with crops To understand the requirement of & water for different crops To know adaptability of crops To know the growing habit of crops To understand climatic requirement of different crops To know the economic produce of the crop plant & its use To know the growing season of the crop Overall to know the actual condition required to the cultivation of plant Ways of classification of crops Classification is done to generalize similar crop plants as a class for attaining better understanding of them. Field crops are classified in the following ways: According to range of cultivation According to the place of origin According to of the crop plants According to plant products come to commercial field According to use of crop plants and their products According to season According to life cycle of crop plants According to cultural requirement According to important uses Classification of crops 1. Range of cultivation i. Garden crops: They are grown on a small scale in gardens. e.g., onion, tomato, maize, etc. ii. Plantation crops: They are grown on a large scale in estates and perennial in nature. e.g., tea, coffee, cacao, etc. iii. Field crops: They are grown on a vast scale under field condition. They are mostly seasonal such as rice, maize, groundnut, cotton etc. 2.: Selected Field Crop Families (Flowering Plants) a. Monocots Poaceae (Gramineae) (grass family) Examples of species; wheat, barley, oats, rice, corn. Aracaceae (palm family) The palm family is tropical and subtropical in adaptation. Examples of species: oil palm (Elaeis guineensis), coconut palm (Cocos nucifera) Amaryllidaceae (amaryllis family) Examples of species: onion, garlic, chives. b. Dicots Brassicaceae (Cruciferae) (mustard family) Examples of species: cabbage, radish, cauliflower, broccoli Fabaceae (Leguminosae) (legume family) The species in this family are an important source of protein for humans and livestock. Examples of species: dry bean, mung bean, cowpea, pea, peanut, soybean, clover. Solanaceae (rightshade family) Examples of species: tobacco, potato, tomato, pepper, eggplant. Euphobiaceae (spurge family) Examples of species: cassava (Manihot esculenta), castor bean Asteraceae (Compositae) (sunflower family) Example of species: sunflower, lettuce. Apiaceae (Umberliferae) (carrot family) Examples of species: carrot, celery. Cucurbitaceae (pumpkin family) The pumpkin or gourd family is characterized by prostrate or climbing herbaceous vines Examples of species; pumpkin, melon, watermelon, cucumber. 3. Commercial classification Based on the plant products which come into the commercial field are grouped as: i. Food crops: Rice, wheat, soybean, groundnut, etc. ii. Food crops/Forage crops: All fodders, oats, sorghum, maize etc. i. Industrial/Commercial crops: Cotton, sugarcane, sugar beet, tobacco, jute, etc.

CLASSIFYING AND NAMING PLANTS IS A SCIENCE GOVERNED BY INTERNATIONAL RULES Who decides what name to give a particular plant so it is universally recognizable? The science of plant taxonomy is coordinated by the International Board of Plant Nomenclature, which makes the rules. The Latin or Greek language is used in naming plants. Certain specific ways of writing the binomial name are strictly adhered to in scientific communication. These rules are as follows: 1. It must be underlined or written in italics (because the words are non- English. 2. The genus name must start with an uppercase letter, and the species name (specific epithet) always starts with a lowercase letter. The term species is both singular and plural and may be shortened to sp. or spp. 3. Frequently, the scientist who first named the plant adds his or her initial to the binary name. The letter L indicates that Linnaeus first named the plant. If revised later, the person responsible is identified after the L, for example, Glycine max L. Merr (for Merrill). 4. The generic name may be abbreviated and can also stand alone. However, the specific epithet cannot stand alone. Valid examples are Zea mays, and Zea, Z. mays, but not mays. 5. The cultivar or variety name may be included in the binomial name – for example, Lycopersicon esculentum Mill cv. “Big Red, “ or L. esculentum “Big Red.“ The cultivar name (cv), however is not written in italics. OPERATIONAL CLASSIFICATION SYSTEMS Crop plants may be classified for specific purposes – for example, according to seasonal growth, kinds of stem, growth form and economic part or agronomic use. Seasonal Growth Cycle Plants may be classified according to the duration of their lifecycle (i.e. from seed, to seedling, to flowering, to fruiting, to death and back to seed). On this basis, crop plants may be classified as annual, biennial, perennial, or monocarp. Annual : Annual plants (annuals) complete their lifecycle in one growing season. Examples of such plants include corn, wheat and sorghum. Biennial: A biennial is an herb that completes its lifecycle in two growing seasons. In the first season, it produces only basal ; then it grows a stem, produces and , and dies in the second season. Perennial: Perennials may be herbaceous or woody. They persist all year round through the adverse weather of the non- growing seasons and then flower and after a variable number of years of vegetative growth beyond the second year. Woody perennials may be categorized into two types: 1. - These are perennials that have green leaves all year round. Some leaves may be lost, but not all at one time. Examples are citrus. 2. - These plants shed their leaves during one of the season of the year (dry, cold). New leaves are developed from dormant buds upon the return of favorable growing conditions. Monocarp - Monocarps are characterized by repeated long vegetative cycles that may go to on for many years without entering the reproductive phase. Once flowering occurs, the plant dies. Common examples are bromeliads (bamboo). Stem Type There are three general classes of plants on stem type. However, intermediates do occur between these classes. Herbs: These are plants with soft, non-woody stems. They have primary vegetative parts and are not perennials. Examples are corn, many potted plants, many annual bedding plants and many vegetables. : A has no main trunk. It is woody and has secondary tissues. Branches arise from the ground level on shrubs. Shrubs are perennials and are usually smaller than . Trees: Trees are large plants that are characterized by one main trunk. They branch on the upper part of the plant, are woody and have secondary tissues. Example is orange. Agronomic Use Crop plants may be classified according to agronomic use. Examples are as follows: 1. Cereals – These are grasses such as maize, millets, wheat, and oats that are grown for their edible seed. 2. Pulses (grain legumes)- These are legumes grown for their edible seed (e.g. peas, beans). 3. Grains – Crop plants grown for their edible dry seed or caryopsis (e.g. corn, soybean, cereals). 4. Small grains – Grain crops with small seed (e.g. wheat, fonio, barley). 5. Forage- Plants grown for their vegetable matter that is harvested and used fresh or preserved as feed (e.g. clover). 6. Roots- Crops grown for their edible (swollen) roots (e.g. sweet potato, cassava). 7. Tubers- Crops grown for their edible modified (swollen) stem (e.g. Irish potato, yam). 8. Oil crops- Plants grown for their oil content. (e.g. soybean, peanut, sunflower) 9. Fiber crops- Crop plants grown for use in fiber production (e.g. jute, flax, cotton). 10. Sugar crops- Crops grown for use in making sugar (e.g. sugar cane, sugar beet) 11. Green manure crops- Crops plant grown and plowed under the soil while still young and green, for the purpose of improving soil fertility (e.g. many leguminous species). 12. Cover crops- Crops grown between regular cropping cycles, for the purpose of protecting the soil from erosion and other adverse weather factors (e.g. many annuals). 13. Hay – Grasses or legume plants that are grown, harvested and cured for feeding 14. Silage crops- Crops preserved in succulent condition by the process of fermentation. 15. Green chop (soilage crop)- Forage that is harvested daily and brought fresh to livestock. 16. Drug crops- Crops grown for their medicinal value. 17. Trap crops- crops planted to protect the main cash crop from a pest. 18. Companion crops- Crops along with another crops for mutually beneficial impact, and harvested separately. 19. Rubber crops- Crops grown for their latex.