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CHAPTER 15 Crop Biodiversity: Naming, Classifying, Origin, and Germplasm Preservation There are over 500,000 different kinds of plants. Naming plants began with simple names that referred to the

1. Use, 2. Growing habit, 3. Other visible attribute.

There are many ways to classify plants, but it is obvious that a uniform and internationally acceptable system is needed to name and classify plants. CLIMATIC AND RELATED CLASSIFICATIONS Fruit and nut crops can be classified according to their suitable climate into:

1. Temperate region Almond, apple, apricot, cherry, peach, pear, pecan, and plum.

2. Tropical region Cocao, cashew and macadamia nuts, banana, mango, papaya, and pineapple.

3. Subtropical region, cannot withstand the severe winters of the temperate zone but may need some winter chilling, Citrus, date, fig, olive, and pomegranate. Some annuals have specific climatic requirements for growth and flowering and are distinguished as:

1. Winter annuals are planted in the fall and bloom early the following spring. 2. Summer annuals are planted in the spring and bloom through the summer

and fall. Some crops grow best in certain seasons and are thus classified.

1. Warm-season plants growing best at average monthly temperatures of 18°C to 27°C Corn, beans, tomatoes, peppers, watermelons

2. Cool-season crops 15°C to 18°C Broccoli, cabbage, lettuce, peas,

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Plants can be classified by the seasons in which they are most likely to flower and fruit or when the quality of the product can be expected to be at its maximum.

1. Early maturing 2. Midseason maturing 3. Late maturing

Vegetables are classified into groups according to their edible parts.

1. Fruits and seeds, Tomato, bell pepper, string bean, pea, and corn.

2. Shoots or leafy parts, Asparagus, celery, spinach, lettuce, and cabbage.

3. Underground parts (either roots or tubers), Carrot, beet, turnip, and potato. Ornamentals are sometimes classified by use

1. House plants, 2. Greenhouse plants, 3. Garden plants, 4. Street trees, 5. Various classes of landscape plants.

The forester classifies trees into two broad groups:

1. Hardwoods Oaks (Quercus), maples (Acer)

2. Softwoods Pines (Pinus)

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COMMON AND BOTANICAL NAMES • Most plants are generally known by their common names because common

names are often easier to remember, pronounce, and use.

• Common names often evolve because of certain plant characteristics.

• Common names are too many and they are too variable to serve most scientific purposes Example: Jasmine, a plant known all over the world and prized for its fragrance, flavoring, and landscaping. Many common plant names contain the word jasmine, Common name (Scientific name) Star jasmine (Jasminum gracillimum) Star jasmine (Trachelospermum jasminoides) Blue jasmine (Clematis crispa) Cape jasmine (Gardenia jasminoides) Crape jasmine (Tabernaemontana divaricatd) Night jasmine (Oestrum nocturnum) Night jasmine (Nyctanthes arbor-tristis) DEVELOPMENT OF BOTANICAL CLASSIFICATIONS Theophrastus (370-285 B.C.) classified plants by their texture or form. He is known as the father of botany for these significant contributions. Carolus Linnaeus (1707-1778) devised a system of categorizing plants that led to the modern taxonomy or nomenclature of plants. Scientific Classification The scientific system of classification has all living things divided into groups called taxa (sing. taxon) based on physical characteristics. The first taxon, called Domain, divides all living things into two Domains:

1. Prokaryotes (cells having no separate subcellular units) and 2. Eukaryotes (cells having subcellular units).

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The Eukaryote Domain is divided into the four Kingdoms of 1. Fungi, 2. Protista, 3. Plantae, 4. Animalia.

The Plantae Kingdom is divided into two groups:

1. Bryophytes (includes mosses and liverworts) and 2. Vascular plants.

The vascular plants are divided into two subgroups:

1. Seedless and 2. Seeded.

Seedless and seeded plants are further classified by Phyla. Seedless phyla include the Pterophyta (ferns). Seeded phyla include

1. Cycadophyta (cycads), 2. Ginkgophyta (ginkgo), 3. Coniferophyta (conifers), and 4. Anthophyta (angiosperms, which are subdivided into

1. monocotyledon and 2. dicotyledon).

Almost all commercially important crop plants are in the seeded group. After phylum, plants are classified in descending rank by

• class, • order, • family, • genus, • species.

Each descending rank more closely defines the physical characteristics common to members of that rank.

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PLANT IDENTIFICATION AND NOMENCLATURE The family is usually the highest taxon commonly included in plant identification or study. Linnaeus used names of Latin form. Most of the names he gave, which describe morphological characteristics of the plants, came from Latin words, although some were derived from Greek and Arabic. The names are usually phonetic and often give a clue to

1. The plant's characteristics, 2. Its native habitat, or 3. For whom it is named. Examples: • Names that refer to leaves include folius, phyllon, or phylla, usually as

suffixes. • The names can also have prefixes, such as macro or micro. For example: macrophylla (large leaf), microfolius or microphylla (small leaf), illicifolius (holly leaf), salicifolius (willow leaf). The Latin for flower is flora; Example: grandiflora (large flower), Shapes or growing habits of plants can be described with altus or alta (tall), arboreus (treelike), compactus (dense), nanus or pumilus (dwarf), repens or reptans (creeping), scandens (climbing). Names based on flower or foliage color include albus or leuco (white), argentus (silver), aureus or chryso (gold), rubra, rubens, or coccineus (red), croceus, flavus, or iuteus (yellow).

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Species names sometimes reflect the plant's place of origin. Examples are australis (southern), borealis (northern), canadensis (from Canada), chinensis or sinensis (from China), chilensis or chileonsis (from Chile), japonica, nipponica, or nipponicus (from Japan), campestris (field), insularis (island), montanus (mountain). Each plant has a two-word, or binomial, name given in Latin.

1. The first name refers to the plant's genus, 2. The second to its species. 3. Complete Linnaean names have a third element—the authority, or the

abbreviated name of the scientist who named the species. Wild or naturally occurring plants and cultivated plants are named according to the same principles but are covered by the International Code of Nomenclature. Some of the basic rules of nomenclature follow.

1. The generic name always begins with a capital letter; it is underlined when written by hand or typewriter and italicized in print. Thus, the genus name for potato is Solanum.

2. The species tuberosum is likewise underlined or italicized and usually begins with a lowercase letter, but it may be capitalized if it is a person's name

3. To complete the binomial name, the authority for describing and naming the plant is given after the genus and species; thus, Solanum tuberosum L. If the plant genus is known but the exact species is not known because it is difficult or impossible to identify. In such a case, the genus name is given and followed by the lowercase letters "sp." for species (singular) and "spp." for species (plural).

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Subspecific Categories A plant group can be so different in the wild from the general species described originally. Botanical Variety Buxus microphylla Sieb. var. japonica Rehd. Buxus microphylla var. koreana Nakai. These botanical varieties are sufficiently different to warrant unique names and authorities to distinguish them from one another. Cultivar In agriculture and horticulture, there are cultivated varieties that remain genetically true. These cultivated varieties may be different from botanical varieties and are called cultivars, a contraction of cultivated variety. There are two main categories of cultivars

1. The clones (if propagated by vegetative methods) 2. The lines (if propagated by seeds).

The word cultivar is abbreviated "cv." and the plural is "cvs." A cultivar is often a distinct variant selected by someone who believed it was uniquely different from any plant already in cultivation. Example: Ilex cornuta cv. Burfordii. The cultivar name is always capitalized but never underlined or italicized. Group The group category is used for some vegetables and some ornamentals such as lilies, orchids, roses, and tulips. A group includes more than one cultivar of a particular kind of plant. For example,

1. When there are evident differences among plants of the same species, they can be further categorized by a group name.

2. When a species has many cultivars, cultivars that are similar are categorized into groups.

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Family The family is a group of closely related genera. The relationship can be based on certain plant structures or on chemical characteristics, such as the presence of latex in the milkweed family ASCLEPIADACEAE, but flower structure is the usual basis for association. Example: The nightshade family SOLANACEAE contains not only Solarium (potato) but also Lycopersicon (tomato). Capsicum (pepper), Nicotiana (tobacco), Datura (deadly nightshade). Petunia, and many others. All species in this family have similar flower structures; (see Fig. 15-4). The first letter of family names is always capitalized and the names are sometimes underlined or italicized. Most families' names end with -aceae (pronounced ace-ay-ee) for example, SOLANACEAE, ROSACEAE, AMARYLLIDACEAE, LILACEAE, and MAGNOLIACEAE. Eight families, however, did not follow this standard rule. For the sake of uniformity, new names have been adopted for these families. The appear in parentheses following the: New names Old names _ ASTERACEAE (COMPOSITAE) BRASSICACEAE (CRUCIFERAE) POACEAE (GRAMINAE) CLUS1ACEAE (GUTTIFEREAE) LAMIACIACE (LABIATE) FAVACEAE (LEGUMINOSAE) ARECACEAE (PALMAE) APIACEAE (UMBELLIFERAE)

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PLANT IDENTIFICATION KEY See Table 15-1 for a simplified yoked (indented) key used to identify some commonly known seed-bearing plants (Spermatophyta). To use a simplified key (Table 15-1), eliminate the alternative that does not pertain to the plant in question, and then proceed to the next pair of numbers directly under the proper choice. Obviously one must be familiar with plant parts and structures (Chapter 8) to use a botanical key and determine the identity of the plant.

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TABLE 15-1 A Simplified Yoked (Indented) Key for Identifying Some Seed-Bearing Plants (Spermatophyta) 1. Ovules and seeds borne naked on scales in cones without typical flowers (Fig. 15-5); trees or shrubs, often evergreen. Gymnospermae

2. Plant foliage palmlike. CYCADACEAE (Fig. 15-7) 2. Plant foliate not palmlike

3. One seed in a cup-shaped, drupelike fruit. TAXACEAE (Fig. 15-8) 3. Many seeds in a dry woody cone 4. Leaves alternate and single

4. Leaves alternate and in clusters; needle-shaped 5. Cone-scale without bracts with two to nine seeds 5. Cone-scales in axils of bracts, flattened, with two seeds. PINACEAE

6. Cones upright on top of branchlets. Abies 6. Cones not upright on branchlets. Pinus

7. Twigs not grooved. White pines or soft pines 7. Twigs grooved. Pitch or hard pines

1 Plants with seeds borne in an ovary (base of pistil) with typical flowers. Herbs, trees, and shrubs. Angiospermae 8. Leaves usually parallel veined, flower parts usually in multiples of three. One seed-leaf or cotyledon. Do not form annual rings when increasing in stem girth. Monocotyledonae

9. Plant with palmlike leaves. PALMAE 10. Leaves fanlike 10. Leaves featherlike. Feather and fishtail palms

11. Lower feathery leaves not spinelike 11. Lower feathery leaves spinelike, fruit fleshy with long grooved seed. Phoenix spp.

12. Plant is a tree with shoots at base, trunk about 50 cm (20 in.) in diameter. Fruit edible. Phoenix dactylifera, date palm 12. Plants not as above. Other Phoenix spp.

9. Plants without palmlike leaves 13. Perianth none or rudimentary

14. Stems solid. CYPERACEAE 14. Stems mostly hollow. GRAMINEAE

15. Plants woody, bamboolike. Bamboos 15. Plants herbaceous, not bamboolike

16. Grasses that produce sugar. Saccharum spp. 16. Grasses that produce little sugar

17. Small grains and their kin (rice, wheat, etc.) 17. Cornlike plants and their kin

18. Plants monoecious. Zea mays, corn 18. Plants not monoecious. Sorghum spp.

13. Perianth present 19. Pistils several, not united. APONOGETONACEAE 19. Pistils one, carpets united, ovary and fruit superior. AMARYLLIDACEAE

20. Anthers six, stem a fibrous rhizome. Agapanthus spp. 20. Anthers six, stem a corm or bulb Allium spp.

21. Leaves large, usually hollow and cylindrical. Bulb rounded and large. Allium cepa, onion 21. Leaves large, usually hollow and cylindrical. Bulb slightly thicker than neck. Allium fistulosum

8. Leaves usually without parallel venation, two cotyledons. Herbs, trees, and shrubs with stems increasing in thickness with cambium cells, which form annual rings in woody plants. Dicotyledonae

22. Corolla absent or not apparent, calyx present or lacking 22. Corolla present, calyx usually forming two series of calyxlike bracts

23. Petals united 23. Petals separate

24. Ovary inferior or partly so 24. Ovary superior

25. Stamens few, not more than twice as many as petals 25. Stamens numerous, more than twice as many as petals

26. Habit aquatic. NYMPHAEACEAE, water lilies 26. Habit terrestrial

27. Pistils more than one, filaments of stamens united into a tube. MALVACEAE 28. Style—branches slender, spreading at maturity, seeds kidney-shaped. Hibiscus spp. 28. Styles united, ovary several carpels, calyx deciduous, seed angular. Gossypium spp.

29. Staminal column long, anthers compactly arranged on short filaments. G. barbadense,sea-island cotton 29. Staminal column short, anthers loosely arranged and of varying lengths. G. hirsutum, upland cotton (Fig. 15-9)

27. Pistil more than one, filaments not united into a tube. ROSACEAE 30. 30. Ovaries superior, fruit not a pome

31. Pistils one, leaves simple and entire. Prunus spp. 32. Fruit soft and pulpy. P. armeniaca, apricot 32. Fruit dry and hard. P. mume, Japanese apricot

31. Pistils two to many, leaves compound (at least basal leaves) 33. Plants woody shrubs. Rosa spp.

34. Styles not extended beyond mouth of hip. Stamens about one-half as long as styles, fl. odorata 34. Styles extend beyond mouth of hip, stamens about as long as styles. R. multiflora

33. Plants herbaceous. Fragaria spp. 35. Underside of leaves are bluish white. F. chiloensis, wild strawberry (Fig. 15-10) 35. Underside of leaves are green. Other Fragaria spp.

30. Ovaries inferior, fruit a pome 36. Fruit with stone cells. Pyrus spp., pears 36. Fruit without stone cells. Mains spp., apples

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ORIGIN OF CULTIVATED PLANTS - The Swiss botanist Alphonse De-Candolle wrote Origin of Cultivated

Plants, first published in 1833. - Later, the famous Russian plant geneticist Nikolai Vavilov also studied the

origin of cultivated plants. The results of his studies were published in The Origin, Variation, Immunity, and Breeding of Cultivated Plants, translated from the Russian and published in English in 1951. Vavilov concluded from his studies that the various cultivated plants originated in eight independent centers: (1) Central China, (2) India, (3) Indochina and the Malay Archipelago, (4) The Turkey-Iran region, (5) The Mediterranean area, (6) The Ethiopia-Somaliland area of east Africa, (7) Mexico and Central America, and (8) The Peru-Ecuador-Bolivia and the Brazil-Paraguay area of South America.(Figure 15-11).

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