The mature stage of an insect which occurs after the nymphal or pupal stages. Adult insects usually have wings and mature sexual organs.
aerobic
Growing only in the presence of molecular oxygen. Having molecular oxygen as part of the environment.
agriculture
The practice of cultivation, farming, tillage and horticulture; plant and animal production.
agroecological zones
Geographical mapping units based on climatic conditions and land forms that determine relatively homogeneous crop growing environments.
agroeconomics
The economics of agriculture.
agronomy
1). Science of agriculture that deals with all aspects of field crop production and soil management. 2). An applied ecological science.
amylose
1). In cereal endosperm, it is the starch fraction of molecules or residues made up of glucose units, straight short chains (see nonwaxy endosperm). 2). The essentially linear fraction of starch, a polymer of glucose (dextrose) with up to 1,000 glucose units. It gives a blue complex with iodine and contributes directly to cooked rice hardness. It is measured colorimetrically by its blue complex with iodine in acetate buffer.
amylose content
The value representing the starch fraction of milled rice, or the amount of starch in the grain that determines its eating and cooking quality. Low-amylose rice varieties are moist, sticky, and glossy after cooking. Rice with a high amylose content cooks dry and fluffy.
anaerobic
The absence of molecular oxygen.
annual
Yearly; used for plants which complete their life cycle (seed to seed production and death) in 1 year or less.
anther
The saclike structure of the male part (stamen) of a flower in which the pollen is formed. Anthers normally have two lobes or cavities that dehisce at anthesis and allow the pollen to disperse.
aquatic plant
A plant that grows and develops in standing water and provides sufficient aeration to the parts under water.
armyworm
The larva of the family Noctuidae which often travels in large populations from field to field. The armyworm moths are ash to light brown, with mottled forewings that have irregular white or light gray spots near the extreme tip or with two pale semicircular spots in the middle. Adults migrate from the grassy areas or upland crops to ricefields and deposit their eggs. The larvae move in armies and may eat entire rice plants.
aroma
A distinct smell or odor.
Asian rice
Oryza sativa L. The cultivated rice believed to have originated in Asia.
azolla
A water fern that fixes nitrogen symbiotically with the blue-green alga Anabaena.
1). A breeding method in which a desired character such as insect resistance is transferred into an improved variety carrying it as a recurrent parent to reinforce or increase the gene frequency of the character. 2). Fl hybrid which is again crossed to either of its parents.
backcross breeding
A method for developing a new variety in which a simply inherited trait is transferred through the backcross method.
bacteria
Any of numerous unicellular microorganisms of the class Schizomycetes, occurring in a wide variety of forms, existing either as free-living organisms or as parasites, and having a wide range of biochemical, often pathogenic properties.
bacterial leaf blight (BLB)
A disease of rice caused by the bacteria Xanthomonas campestris pv. oryzae. The leaf stage of BLB is the most widespread and, therefore, causes the most damage. The early symptoms include yellow, undulating lesions along the margins of the upper portion of the leaf blades. The lesions develop rapidly parallel to the veins and extend laterally to the healthy regions. In extreme cases, a large portion of the entire leaf blade becomes infected, turns yellow or dirty white, and finally dies.
bacterial leaf streak (BLS)
A bacterial disease of rice caused by Xanthomonas oryzae pv. oryzicola. The organism attacks chiefly the parenchymatous tissue between the leaf veins and, in the early stages, remains confined to the interveinal spaces. It may enter the leaf through the stomata or through wounds which are mainly caused by storms. The symptoms manifested are the appearance of fine, interveinal, long or short lines which are water-soaked and grayish. The lesions extend and coalesce to form larger patches and become yellow from the death of cells. At this stage, the symptoms are difficult to distinguish from those of bacterial leaf blight. The disease is limited to the tropics.
biodiversity
The totality of all the species of plants and animals in an area.
biological control
The action of natural enemies--parasites, parasitoids, predators, and pathogens--in maintaining another organism's density at a lower level than it would occur in their absence. If control is facilitated by man, it is called applied biological control. If not, it is called natural biological control.
biological insect control
A method of pest control that relies on beneficial enemies to reduce pest populations to tolerable levels. It involves human manipulation of natural enemies of insects.
biotechnology
1). Any technique that manipulates living organisms (or parts of organisms) to make or modify products, to improve plants or animals, or to develop microorganisms for specific uses. An applied biological science--e.g., recombinant DNA technology. 2). The various industrial processes that involve the use of biological systems; the collection of microbial and other biochemical processes carried out on an industrial scale. It includes, but is not limited to, the industrial aspects of genetic engineering. Other areas of biotechnology deal with fermentation technology (antibiotics), hybridoma technology (monoclonal antibodies), and agricultural technology (plant and animal transformation).
blast
A disease caused by the fungus Pyricularia grisea. Leaf lesions are typically spindle-shaped, wide in the center and pointed toward either end. Large lesions usually develop gray centers. The disease can have different forms: leaf blast, node blast, or neck blast. Lesions on panicle neck nodes may result in empty panicles (often called rice blast), \"rotten neck\" or \"neck rot\" symptoms.
blight
1). Any agent causing widespread white coloring, yellowing or blackening necrosis of leaves and shoots. 2). A plant disease symptom characterized by the presence of extensive necrotic areas on plant organs.
block
A grouping of experimental units made according to homogeneity of experimental units, sometimes called replication. Blocking is an effective way to control experimental error. If the number of experimental units in a block is equal to the number of treatments, the block is said to be \"complete\" (and is equivalent to replication). Otherwise, it is \"incomplete.\"
bold grain
Grain that is broad in shape.
boot
A rapidly growing panicle enveloped by the flagleaf sheath. In tissue culture, this refers to the panicle collected when the distance between the collar of the flagleaf and subtending leaf is about 7 to 8 cm.
booting
The bulging of the leaf sheath due to increase in size of the young panicle and its upward extension inside the upper leaf sheath.
booting stage
The reproductive phase of rice growth and development when the developing panicle causes a swelling of the culm. The swollen area is referred to as the boot.
borer
An irrigated, high-yielding, cold-tolerant, relatively pest-free and photoperiod-insensitive rice cultivated during the winter months in India and Bangladesh.
breeder seed
Seed of the highest genetic purity produced for maintaining purity of a variety. It is used to produce foundation seed.
breeding
The art and science of improving plants and animals genetically for the benefit of mankind.
breeding line
A genetic line bred in a crossing program, before it is named and officially released for commercial cultivation.
broadcast
a sowing of seed by scattering it
broadcast planting
A method of planting in which the seeds or seedlings are dropped or thrown over the entire surface area of the field.
broadcasting
The action of spreading seeds, fertilizer, or pesticides on the surface of the field at random, by hand or by machine.
broken grain (brokens)
Grain that has broken into two or more pieces during milling.
brown rice
Rice grain with its hulls removed but not polished.
brown spot
A disease of rice caused by the fungus Helminthosporium oryzae, with leaf symptoms consisting of brown and oval spots with gray or whitish centers. The disease is also observed on the grains. The disease is closely associated with abnormal or poor soil and its occurrence serves as an indicator of poor soil conditions for rice production. It is sometimes called \"poor man's disease.\"
bud
A short embryonic stem tip bearing leaves or flowers or both.
bug
A loose term used for a number of insects referring to the suborder Hemiptera, including winged and wingless species. In the strict sense, it refers to suborder Heteroptera.
bulk breeding method
The growing of genetically diverse populations of self-pollinated crops in a bulk plot with or without mass selection, followed by single plant selection.
bund
An embankment used to control the flow of water; a division between fields.
by-product
A substance obtained during the manufacture of another substance, e.g. bran is a by-product of milled rice.
Adjustment of model parameters to obtain model behavior that corresponds with observed behavior.
Caryopsis
The dehulled rice grain.
caseworm
Insect of the species Nymphula depunctalis whose larva lives in a case consisting of a piece of rolled rice leaf.
cercospora leaf spot
A disease caused by the fungus Cercospora janseana characterized by the presence of short, elliptical to linear, brown lesions mainly on the leaves but also on leaf sheaths, pedicels, and glumes. The lesions are 2-10 mm long and 1 mm wide. Also referred to as narrow brown leaf spot
cereal
Seeds of flowering plants of the grass family (Graminaceae) cultivated for the food value of their grains, e.g., rice, wheat, sorghum, maize, oat, barley, rye, and millet.
certified seeds
Seeds used for commercial crop production produced from foundation or registered seeds under the regulation of a legally constituted agency. In hybrid rice, they are first generation seeds produced directly from CMS x restorer lines grown as per certification standards.
clod
A compact coherent mass of soil, varying in size. Usually produced by breaking up soil by plowing, especially when performed on clayey or fine-textured soils that are either too wet or too dry. Seldom occurs in sandy soil.
coleoptile
The cylinder-like protective covering of the young plumule.
concentration
The quantity of active ingredient expressed as mass per unit volume, or an amount of a substance based on its proportion to the whole or a specified amount and expressed as mass per unit volume of the resulting solution or mixture, e.g., g/l, ppm.
crop
Plants on a farm that are managed for economic purposes, producing a physical product for farm use or sale.
crop injury
Visible and measurable symptoms and/or signs caused by physical or biological pathogens, insects, weeds, and other factors.
crop loss
A reduction in value and/or financial return due to damage; often measured as the difference between actual yield and attainable yield due to the effects of one or more pathogens or pests.
crop rotation
A planned sequence of growing crops in a regularly recurring succession on the same area of land, as contrasted to continuous culture of one crop or growing different crops in a haphazard order.
cross
A hybrid between two genetically dissimilar parents.
cultivar
1). A variety. 2). A cultivated variety; the international term for variety.
cultivate
1). Preparing the land for planting or sowing seed. 2). To grow crops or plants.
cultural practices
Activities or operations that are usually carried out in raising field crops, e.g., land preparation, seed selection, crop establishment, fertilization, etc.
cutworm
Scientific name: Spodoptera litura. A pest primarily of upland rice. Lowland rice suffers only from cutworm larvae migrating from adjacent grassy areas. Seedlings may be cut at ground level; the larvae defoliate older plants.
Those distinctly discolored or damaged by water, insects, heat, or any other means (includes yellow grains).
dapog
Method of raising rice seedlings on banana leaves, polythene, or a cement slab. Seedlings are raised in the same way as in the wetbed method. Because the seeds are sown thickly (3 kg seeds per square meter), seedlings look like a mat or carpet and can be rolled for transplanting when they are 10-14 days old.
data
The collection of facts of experiments, instruments, and surveys and treatments that are calculated statistically to give measured statistical results.
deepwater rice
A long-duration rice that grows under rainfed, nonflooded conditions for 1-3 months, then is subject to flooding with water depths more than 50 cm for a month or longer. Plants elongate as the flood rises, above the water, in normal flood conditions, but may be submerged in deep flash floods. Maximum water depth varies greatly.
deficiency
Any inadequacy or shortage of substances essential to growth and development of plants. Lacking in some quality, faculty, or characteristic necessary for completeness.
defoliator
Any chewing insect that feeds on the leaves of plant, or chemical that removes foliage.
degree of milling
Percent efficiency of bran removal from brown rice during milling; done visually with well-milled rice as 100% milled (Indonesia, Bangladesh). Thailand classifies milled rice into ordinary, reasonably well-, well-, and extra well milled.
demonstration plot
A plot that shows the characteristics or evidence for the local people to observe; planted specifically as a demonstration at a research station.
density
Quantity or number per unit volume or area.
depth
A measurement from the top to the bottom, e.g. from the surface of the water to the ground or to the bottom of a container.
direct seeding
A system of planting rice in which seeds, either pregerminated or dry, are broadcast or sown directly in the field, with either dryland or wetland preparation; no transplanting process is involved.
disease
A harmful deviation from the normal functioning of physiological and biochemical processes caused by plant pathogens (fungi, viruses, bacteria, parasites).
disease resistance
Ability of the plant to survive and grow without symptoms of the disease that has infected it.
dissemination
The distribution of germplasm, information, etc.
donor
In plant breeding, a variety that serves as a source of characteristic such as insect resistance.
dormancy
A physical or physiological condition of a viable seed that suspends or prevents germination even in the presence of otherwise favorable germination conditions.
dough grain
The stage when the milky portion of the grain turns into a soft massand later into a hard mass.
dough stage
The stage in rice development which occurs during the ripening phase when the milky caryopsis inside the developing grain turns into soft dough and later into hard dough.
dress
To apply a chemical such as an insecticide or fungicide to seeds before planting or storage.
drought
An insufficient supply of moisture from precipitation or soil for optimum plant growth.
drought tolerance
A total expression of the plant's ability to stay alive, grow, and ultimately produce grain, with part of its life cycle under water stress.
dry season
The season when no rain is expected.
dry seeding or dry (DSR)
A method of rice establishment where rice seeds are broadcast on dry soil (unpuddled). The technique is more popular in upland unbunded areas, where the soils are light-textured and easily drained. It can also be practiced in wetland areas, when the field is prepared at the time of early germinating rain.
drybed method
Raising seedlings on a dry seedbed. It is usually practiced in rainfed areas or where irrigation water is not adequate.
dwarf variety
A rice variety that is short in stature (with a plant height of 85±5 cm).
1).A major interacting system that involves both living organisms and their physical environment. 2). A system of ecological relationships in a local environment, including relationships between organisms and the environment itself.
egg
The female ovum, pertaining to reproductive cells.
elongation ability
1). Deepwater rice: The ability of the internodes, leaves, and leaf sheath to elongate during the vegetative growth phase, thereby escaping submergence by rapidly rising floodwater. Floating rice can elongate as fast as 20 cm per day. 2). Grain: The ability of the rice kernel to stretch lengthwise upon cooking to sometimes twice its original length or more in some high quality Basmati rice varieties.
emergence
Coming out or rising of seedlings from the ground; coming out of panicles from the boot (panicle exsertion); coming out of adult insect from cocoon or pupa.
endosperm
The nutritive tissues of the ripened ovary, consisting of the aleurone layer and the starchy endosperm. It serves as food for the germinating embryo; triploid in chromosome number.
environment
The total external conditions and surrounding organisms, physical and biological factors which affect the growth and development of an organism.
equilibrium moisture content
The condition wherein the moisture-retaining tendency of the grain is the same as the moisture-withdrawing tendency of the air.
erosion
The loss of soil particles and nutrients when the surface soil is carried away by wind, water, or other agents.
establish
To begin; to become embedded and grow in the soil; to plant the crop; to be a part of a certain practice, functioning group, society, or organization.
evaluate
To examine and estimate the amount and degree of a character and to express it numerically.
extension
Dissemination of agricultural technology from scientific research organization to the farming community to improve their farming practices.
The second filial generation obtained by self-fertilization of F1 individuals.
fallow
Land that is ordinarily used for crops but allowed to lie idle between crops.
farming system
1). The manner in which a particular set of farm resources is assembled within its environment, by means of technology, for the production of primary agricultural products. 2). A collection of distinct functional units, where crops, livestock, and marketing activities interact because of the joint inputs received from the environment and management personnel. 3). A unique and reasonably stable arrangement of farming enterprises that a household manages according to well-defined practices in response to the physical, biological, and socioeconomic environment and resources. These factors combine to influence output and production methods.
female flower
A flower with functional ovary but no stamens.
fertile
1). Land that has enough nutrients to support abundant plant growth. 2). Plants that are reproductive and can produce fruits, seeds, spores or pollen grains.
fertilization
The union of the pollen (male) and the egg (female) initiating reproduction.
fertilizer
Any substance added to the soil to supplement elements required in the nutrition of plants.
fertilizer requirement
The quantity of certain plant nutrient elements needed, in addition to the amount supplied by the soil, to increase plant growth to a designated level.
fertilizer, complete
Used formerly to denote a fertilizer containing appreciable amounts of N, P, and K; it now includes secondary and micronutrients essential to plant growth.
field
Cultivated open land area; land used for raising crops or for conducting experiments.
Fl
Abbreviation for the first filial generation, usually the hybrid between two homozygous types.
Fl hybrid
Denotes the first generation offspring from the mating of two parents.
floating rice
Rice that can maintain their canopies above the water in slowly rising flood as deep as several meters. It can take gradually increasing water level up to several meters at a maximum rate of 15 cm per day, provided there is adequate growth at the seedling stage approximately six weeks before the onset of flooding. Examples are floating rice varieties grown where maximum water depth ranges between 1 and 6 m for more than half of the growth duration. In densely populated areas, floating rice is grown as a subsistence crop because no other crop will grow.
flooding
1). The normal process that floods the plains where deepwater rice is grown. 2). To apply water to the field for the benefit of saturating the soil for land preparation. 3). Establishing and maintaining an irrigated rice crop.
floret
A unit of the spikelet, including the lemma, palea, and the flower.
flower
The reproductive part of the angiosperms. In rice, it consists of two lodicules, six stamens, and the pistil.
flowering
The stage when the anthers of the terminal spikelets protrude and shed pollen.
foundation seed
Seed stock produced from breeder seed by or under the direct control of an agricultural experiment station. Foundation seed is the source of certified seed, either directly or through registered seed organizations.
fumigation
The process used to destroy bacteria, insects, or pests by smoke or exposure to poisonous gas.
fungicide
A chemical agent that kills or inhibits fungal spores or mycelium. A pesticide used to treat or prevent diseases caused by pathogenic fungi.
fungus
1). An organism with no chlorophyll, reproducing by sexual or asexual spores, usually having mycelia with well-marked nuclei. 2). Heterotrophic microorganisms chiefly saprophytic or parasitic, that constitute the kingdom fungi.
An insect pest (Orseolia oryzae) that causes the youngest leaf or the shoot in a tiller to appear as light-colored tubular gall resembling an onion leaf. Tillers with gall midge do not produce panicles.
gel consistency
Degree of rice gel firmness measured as the length of cold milled rice gelatinized in 2 ml of dilute potassium hydroxide in a 13- x 100-mm test tube, placed horizontally for 30 minutes or 1 hour. Gel consistency may be classified as hard (27 to 40 mm), medium (41 to 60 mm), or soft (61 to 100 mm). It is correlated with hardness of cooked rice.
gender roles
Learned behaviors that condition activities, tasks, and responsibilities viewed within a given society as \"masculine\" or \"feminine.\"
gene
1). A functional hereditary unit that occupies a fixed location in a chromosome, has a specific influence on the phenotype (usually) through encoding a single polypeptide chain or molecule), and is capable of mutation to various allelic forms. 2). DNA segment that performs a specific function and is a unit of inheritance.
germination to emergence
The period which is signified by the coming out of the radicle or coleoptile from the germinating embryo.
germplasm collection
A collection of genotypes of a particular species, from different sources and geographic sites, used as source materials in plant breeding.
glutinous rice
Refers to waxy rice with only 0-2% amylose or mainly amylopectin in its endosperm and pollen starch. Raw glutinous endosperm is opaque and becomes moist, sticky, and glossy when cooked.
grain characteristics
The different character and dimensions of the rice grain, e.g. length and shape and cooking qualities.
grain dormancy
Physiologically, the inactive growth phase of the grain.
grain shape
The physical shape of the rice grain--round or slender, etc.
grain size
The dimensions and weight of the grain.
grain yield
Weight of harvested grain expressed as tons/ha with a moisture content of 14%.
green leafhopper
A rice pest, Nephotettix spp., prevalent in Asia that can cause hopperburn and also pronounced yellowing and stunting, by transmitting the yellow dwarf virus and tungro diseases in rice.
green revolution
A term used to describe the success in increased crop production throughout Asia, commencing in the 1960s as a result of high-yielding rice varieties developed by IRRI and wheat varieties by CIMMYT.
Walk-behind, two-wheel tractor commonly used for land preparation in wetland rice. Also called power tiller.
hard dough stage
Stage when the rice grain is almost fully ripe.
hard pan
A physically compacted soil layer restricting root growth and water movement through it.
harrow
A cultivating implement usually with spikes or teeth used for secondary tillage to pulverize and smoothen the soil, mulching, covering, or removing weeds--e.g., comb-tooth or spike-tooth harrow and wooden plank.
harrowing
A secondary tillage operation which pulverizes, smoothens and firms the soil in seedbed preparation. It controls weeds or incorporates material spread on the surface into the soil.
harvesting
The process of gathering in a crop; in the case of rice, the gathering in of mature rice panicles from the field.
head rice
The whole grains of milled rice that can be obtained from a given quantity of clean rough rice (paddy). It is usually expressed as a percentage of rough rice. Broken rice larger than 3/4 of a grain is also considered as head rice. Head rice may vary from as low as 25% to as high as 65%.
heading
The emergence or coming out of the panicle from the flag leaf sheath.
headland pattern
A plowing technique that makes a dead or back furrow plowing pattern. This technique is used in many plowing operations but especially in large operations using large tillage equipment.
hectare
A measurement of land area in the metric system equivalent to 10,000 m2.
herbicide
A chemical used for killing or inhibiting the growth of certain plants or weeds.
hill
A group of rice plants directly adjacent to each other because the seeds or seedlings were planted together. A hill may also consist of only one plant.
hull
The outermost covering of the rice grain which provides protection to the rice caryopsis composed of lemma and palea. It ranges from 17 to 24% of the rough rice content.
husk
see \"hull\"
hybrid
The product of a cross between genetically dissimilar parents.
hybrid variety
1). A variety of rice developed from crossing and selection to gain higher yields. 2). Fl offspring of two genetically dissimilar parents.
hybridization
A breeding method in which two varieties are crossed to generate new variability and to produce desired recombinants. The hybrids are allowed to self-pollinate and the segregating populations are handled by an appropriate method.
Grains with still greenish caryopsis or brown rice.
immune
Completely resistant to pest or disease of the plant.
improved cultivar
A rice variety that has been bred to increase production.
improved plant type
Specific morphological and physiological features of the rice plant that make it more efficient and higher yielding.
inbred
An individual resulting from the mating of closely related parents or selfing.
indica rice
One of the two major ecogeographical races of Oryza sativa (see also japonica). The major type of rice grown in the tropics and subtropics. It has broad to narrow, light green leaves and tall to intermediate plant stature (except for the semidwarf). Indica plants tiller profusely. Grains are long to short, slender, somewhat flat, and awnless. Indica grains shatter easily and have 23-31% amylose content. They grow mostly in the Philippines, India, Pakistan, Java, Sri Lanka, Indonesia, central and southern China, African countries, and other tropical regions.
infection
A stage in a disease cycle when the pathogen penetrates and establishes a parasitic relationship with the host.
infest
To attack externally, e.g. by insect pests; attack on a part of a plant such as grain of rice. Also to contain the parasite.
inorganic fertilizer
Fertilizer materials derived from minerals, atmospheric gases, water, and inert materials. Can be natural or synthetic products of chemical reactions.
insect
Members of the phylum Arthropoda (\"jointed legs\"); they have six legs, three distinct body regions (head, thorax, and abdomen), one pair of antennae, and usually wings.
insecticide
A chemical used for killing insects.
integrated pest management (IPM)
A strategy that utilizes various tactics or control methods (cultural, biological, and chemical) in a harmonious way in which control actions are based on frequent monitoring of the pest. IPM depends on multidisciplinary ecological strategies to weigh the effect of each tactic, as part of the agroecosystem, in producing the least disturbance and yield loss in the long run.
irrigated rice
Rice which is supplementary or fully supported with water supplied by artificial means.
irrigation
The artificial supply of water to areas by ditches, pipes, etc. by pumping or gravitation to the soil for the purpose of growing crops.
One of the two major ecogeographical races of O. sativa (see also indica).A group of rice varieties from northern and eastern China grown extensively in some areas of the world. It has narrow, dark green leaves, medium-height tillers and short to intermediate plant stature. It is found in the cooler zones of the subtropics and in the temperate zones. Grains are short, roundish, spikelets awnless to long-awned, panicles low-shattering, and have 0-20% amylose content.
javanica rice
Designation for the bulu and gundil varieties of Indonesia and many upland rices. They belong to the japonica race of O. sativa. Rice varieties with broad, stiff, light green leaves. It is low-tillering and has a tall plant stature. Grains are long, broad, and thick, awned or awnless. Javanica grains are low-shattering and have 0-25% amylose content.
The grain or seed of cereal or grass enclosed in a hard husk.
The process of preparing the soil for planting, to provide a soil environment favorable for plant germination and/or growth.
larva
The immature, wingless, and often vermiform (wormlike) feeding form that hatches from the egg of many insects, alters chiefly in size while passing through several molts, and is finally transformed into a pupa or chrysalis from which the adult emerges.
laser leveling
Land leveling technique wherein the leveling device, normally tractor-drawn, is controlled by a laser beam set at a certain bench mark or level.
leaf blast
A rice disease caused by the fungus Pyricularia oryzae. Symptoms consist of elliptical spots with pointed ends, with gray or whitish center, and with brown or reddish brown margin.
leaf curling or rolling
Rolling of the leaves to control water loss affected by lack of atmospheric or soil moisture. Also the bending or twisting of the leaves due to viral disease (as in rice ragged stunt) or to other harmful agents.
leaf sheath
The lower part of the leaf enclosing the stem, originating from a node and wrapping around the culm above the node.
leaf veins
The vascular bundles of the leaf. In monocotyledonous plants such as rice, leaf veins are seen as longitudinal ridges.
leaffolder
The insect Cnaphalocrocis medinalis which causes damage by making a leafy tube and feeds within the tube consuming the leaf tissues except the epidermis.
leafhopper
Insect of the order Homoptera, family Cicadellidae, which feeds by sucking sap from leaf veins of the rice plant. They have more slender bodies and move more quickly than planthoppers.
leveling
Land preparation involving moving soil from high to low spots in the field to achieve a flat horizontal surface so that irrigation water will be evenly distributed throughout the field.
line
In plant breeding, plants originating from common parents or a common cross that is undergoing selection or improvement and which may become identified as a variety.
lodge, lodging
The falling down of rice plants in the field due to wind, rain, flooding, pest damage, or because the stems are too tall or too weak to stand erect during the grain-filling stage, usually causing yield loss.
long-duration varieties
Varieties that mature in 150 days or more.
lowland field
A land area surrounded with dikes or levees to impound rain or irrigated water. An irrigated field surrounded by levees.
lowland rice
Rice grown on fields where water is held by bunds. About 30% of the world's rice is grown as rainfed lowland; about 45% as irrigated lowland. Some areas are flooded lowlands.
A flower with functional stamens but no ovary.
mangrove
Tropical or subtropical vegetation (mainly trees) typical of tidal swamps.
manure
Material used as fertilizer (e.g., organic material and excreta).
mass selection
A breeding method wherein a large number of plants having the desirable traits are harvested individually from a standing crop. The seeds from all selections are then bulked. From the bulk, a seed sample is taken and used to plant a population from which desirable plants are selected at maturity. The procedure is repeated for several cycles until the population becomes uniform and homogeneous. A variety developed by mass selection is fairly uniform and contains fewer genotypes than the original population.
mature grain
The stage when the rice grains in the panicle are yellow, fully developed, and hard.
microclimate
The climatic condition of a small area, such as a ricefield, resulting from the modification of the general climatic conditions by local differences in elevation or exposure. Also the environmental conditions below the crop canopy.
milk grain
The stage when the watery consistency of the caryopsis turns milky.
milled rice
Rice from which the hull and bran have been removed.
milling
The process of separating the hull or husk and bran from the paddy or rough rice into milled rice and bran-and-chaff.
milling yield / recovery
The estimate of the quantity of head rice (whole rice or nearly whole kernels) and of total milled rice that can be produced from a unit of rough rice. It is generally expressed as a percentage.
minerals
Solid particles other than organic matter which act as major components of soils and sources of nutrient elements.
modern varieties (cultivars)
Dwarf, semidwarf, stiff-stemmed, high-tillering, nitrogen-responsive, photoperiod-insensitive, high-yielding varieties. Their characteristics are different from those of traditional varieties.
moisture content
The amount of water measured in the soil or plant. Expressed as percentage moisture based on total fresh weight of the substance.
mold
(1) A cavity where a molten metal is shaped, as in casting. (2) A downy or furry growth on the damp surface of organic matter, generally caused by saprophytic fungi with conspicuous mycelia or spore masses.
monsoon
The cyclic surface winds blowing in tropical and subtropical latitudes for several months from the southwest, switching for several months from the northeast, and the rains that accompany them.
morphology
A branch of biology that deals with the physical form and structure of plants and animals. A study of the forms, relations, metamorphoses, and phylogenetic development of organs apart from their functions.
mulch
Organic material that is used to protect the soil. Any material, such as straw, sawdust, leaves, plastic film, loose soil, etc., that is spread upon the surface of the soil to protect it and plant roots from the effects of raindrops, soil crusting, freezing, evaporation, etc.
multiple cross
A cross involving more than two parents.
Any of the class or phylum Nematoda of elongated cylindrical worms parasitic in animals or plants free-living in soil or water. Generally microscopic, wormlike animals that live saprophytically in water or soil.
nitrogen deficiency symptoms
Characteristics of a plant at suboptimal N supply usually indicated by yellowing leaves, reduced tillering, and stunted growth.
node
1). The joint of a stem from which leaves or branches arise. 2). The solid portion of the culm, panicle axis, and panicle branches. Leaves, tillers, and adventitious roots arise from nodes on the culm.
nursery
A piece of prepared land where crop seedlings are raised for a short time pending their planting in permanent sites. A place where a large number of introduced or breeding varieties or lines are first looked at or screened under field conditions.
nutrient
A chemical element essential for the growth and development of an organism.
nutrient stress
A condition of plant growth when inadequate nutrient supply restricts growth.
Goal or purpose. In research, it is usually testing of hypothesis within the experimental framework.
opaque
Impervious to the rays of visible light: not transparent or translucent, e.g., the glutinous endosperm of the rice grain.
organic fertilizers
Fertilizer materials derived from plant and animal parts or residues.
outbreak
A sudden increase in pest population resulting in economic damage to the rice crop.
ovary
The bulbous, basal portion of the pistil containing one ovule.
1). Wetland rice. 2). Bunded and leveled field used for cultivation of rice. The original meaning of paddy (Malay padis) is threshed, unhulled rice.
Pan
See \"hard pan\"
panicle
1). An inflorescence with a main axis and at least primary and secondary branching. 2). The terminal shoot of a rice plant that produces grain.
panicle initiation
The stage when the vegetative primordium turns to a reproductive primordium.
panicle primordium
The panicle at its rudimentary (earliest) stage of the development.
parasite
An organism living in or on another living organism, obtaining from it part or all of its organic nutrients, and commonly exhibiting some degree of adaptive structural modification.
parboiled rice
Rough rice soaked overnight or longer in water at ambient temperature, followed by boiling or steaming the steeped rice at 100 °C to gelatinize the starch. The rice is then cooled and dried before storage or milling. In this way part of the vitamins and minerals of the bran permeate the endosperm and are thus retained in the polished rice.
pedigree
The ancestral history of an individual or family.
pedigree method (breeding)
A system of breeding in which individual plants are selected in the segregating generations from a cross on the basis of their desirability judged individually and on the basis of a pedigree record.
percolation
The downward movement of excess water through the soil.
pest
An organism which competes with other organisms for food and shelter, or threatens their health, comfort, or welfare.
pest control
The control of pests in the ricefield by selective cultivation methods influencing natural factors or predators or by using chemical/physical control methods to reduce pest damage to rice plants.
pH
A measure of the degree of acidity or alkalinity of a soil or solution. A pH of 7.0 is neutral, below 7.0 is acidic, and above 7.0 is alkaline or basic. It is the negative logarithm of the hydrogen ion concentration of a soil or solution.
phosphorus (P)
Essential element for plant growth and development.
photoperiod
The duration of the light period during a given day, which fluctuates during the year and according to latitude.
photosynthesis
A complex process by which the energy of sunlight is absorbed and set to drive chemical reactions. In plants, the major role of photosynthesis is to reduce CO2 to the level of carbohydrate in the presence of chlorophyll and light and release oxygen as a by-product.
Pistil
The female reproductive organ consisting of the ovary, style, and stigma.
planthopper
An insect of the order Homoptera, family Delphacidae, which feeds by sucking sap from leaf veins along the lower portion of the rice plant; usually more stout and slow-moving than leafhoppers. Planthoppers have a mobile spur called a \"calcar\" at the tip of the tibia of the hind leg.
plumule
The embryonic leaves of the young plant in the embryo. It is enclosed by the coleoptile.
pluvial rice
Upland rice that depends only on rainfall for water supply.
pollen
A mature reproductive male germ cell, microscoporocyte, specialized for fertilization.
pollen shedding
The falling of pollen grains from the anthers to the pistil.
population
1).In genetics, a community of individuals which share a common gene pool at a given site. In statistics, a hypothetical and infinitely large series of potential observations among which actual observations constitute a sample. 2). A group of individuals (plants) within a species or a variety that are found at one site or field. Plants in the population may or may not be genetically alike.
potassium
A reactive alkali metal element essential for plant growth and proper development.
predator
An animal that attacks and feeds on the other animals, such as a bird or spider which feeds on many different species of insects and attacks a number of prey by quickly eating or sucking their body fluids.
pregerminated seeds
Seeds soaked in water for 24 hours and incubated for 24-48 hours until sprouting is visible.
pregermination
The process of making the seed sprout before sowing or direct seeding. Soaking and incubating the seed hasten sprouting.
primary leaf
The first seeding leaf, without a blade.
primary tillers
Tillers arising from the lowermost nodes of the main culm.
progeny
Offspring; individuals resulting from mating.
puddled soil
A soil whose structure has been mechanically destroyed, allowing the soil to run together when saturated with water. A soil that has been puddled is usually in a massive nonstructural state.
puddling
Turning the soil into a muddy or watertight paste through secondary tillage.
pure line
1). A line that has been made almost completely homozygous by repeated self-pollination and selection of a specific type (or by the removal of off-types) over generations. 2). A group of identical individuals that always produce offsprings of the same phenotype when intercrossed.
pure seed
Has a high level or purity with little or no contamination of other varieties or species. Seeds give rise to genetically similar plants.
quantitative trait locus (QTL)
A genomic region which governs a phenotype by interaction with other genes.
A genetically and often geographically distinct mating group within a species; or a group of pathogens that infect a given set of plant varieties.
radicle
The embryonic primary root.
rainfed lowland
Bunded fields where water depth does not exceed 50 cm for more than 10 consecutive days and the fields are inundated for at least part of the season. Such fields have no access to an irrigation system, but may have on-farm rainwater conservation facilities.
rainfed rice
Rice grown on leveled bunded fields to allow an accumulation of flood water on the surface during heavy rains. Grown in areas that depend entirely on rain for moisture for its water supply.
range
The variation of data from highest to the lowest value.
rating
Classifying test entries based on degree of plant damage, number of insects, etc., by expressing on a numerical scale, usually 0-9. It is relative estimate.
recession
Complete draining of flood water from the land.
recovery
Plants that have the ability to grow after being exposed to unfavorable seasonal conditions or after being attacked by pest or disease.
recurrent parent
The parent to which successive backcrosses are made in backcross breeding.
red rice
A rice kernel that has a red seed coat frequently found in African rice Oryza glaberrima or some Oryza sativa cultivars.
registered seed
The progeny of foundation seeds normally grown to produce certified seed.
reproductive phase
The period from panicle initiation to flowering.
residual effect
The effect of chemical fertilizers, herbicides, insecticides, or fungicides that remains in the following crop season without fresh application of the chemical.
residue
The plant part left after the economically useful part has been harvested.
resistance
The inherent ability of an animal or plant body to resist (oppose, counteract) untoward circumstances such as insect attack, diseases, toxic agents, or infection.
resistant variety
A variety which has genetic resistance to an adverse factor or pest. It is genetically able to suppress or retard the activity of a pathogen or insect. A variety which has genetic resistance to or tolerance for all adverse factors or pests.
ripening phase
The period from flowering to mature grain.
rodents
Rats, mice, and guinea pigs.
rogueing
Judicious removal of infected and undesirable individuals from a pure population (variety) to prevent spread of disease and to purify the stock.
root
The underground part of a seed plant body that originates usually from the hypocotyl, and functions as an organ of absorption, aeration, and food storage or as a means of anchorage and support. Types: a) primary. the root developing from the radicle that first appear from the seed; b) secondary. developing from the primary root; branch roots; c) tap. a primary root that enlarges and grows downward.
rough rice
(syn. paddy rice) Called paddy, threshed, unmilled or whole rice grain, or caryopsis.
rust
A disease caused by a fungus. Called rust because it releases reddish-brown powdery masses of uredospores.
A soil containing soluble salts with sufficient exchangeable sodium to interfere with the growth of most crop plants. Soil whose saturation extract has an electrical conductivity greater than 4 dS/m, sodium adsorption ratio greater than 15, and pH less than 8.5 (See saline soil and sodic or alkali soil).
saline soil
A soil that contains sufficient salt in the root zone to impair plant growth. Its electrical conductivity is greater than 4 dS/m and exchangeable sodium percentage is less than 15.
salinity
The state of consisting of or containing salt.
salinity symptoms in rice
Leaves usually become whitish or chlorotic, growth is stunted and uneven, tillering is reduced.
sample
A finite series of observations taken from a population; a portion of a population. Individuals taken from a population to represent it.
sample size
The number of sampling units to be measured per plot, e.g., number of plants to be measured per unit area.
saturate
1). To be totally wet, to fill all the voids between soil particles with a liquid. 2). To fill completely or load to capacity.
screening
Evaluation of varieties or breeding lines for resistance where the resistant ones are selected for further studies and possible use as donors in the breeding program and the susceptible are eliminated.
secondary adventitious roots
Roots arising from the nodes at the base of the plant.
secondary tillers
Tillers arising from primary tillers.
sediment
Solid particles transported and deposited by water, glaciers and wind.
seed
The fertilized and ripened ovule of a seed plant, comprising a miniature plant usually accompanied by a supply of food (endosperm) enclosed in a protective seed coat, often accompanied by auxiliary structures, and capable, under suitable conditions, of independent development into a plant similar to the one that produced it. In rice, the grain is the common form of seed; the caryopsis is the true seed.
seed quality
1). The properties of the seed such as cleanliness, germination percentage, moisture content, shape, purity, and desirable characters for research. 2). The export qualities of the seed, the size, shape, moisture content, protein content, color, chalkiness, and other properties as desired by the millers or traders.
seed viability
The ability of seeds to germinate under favorable conditions and develop normal seedlings.
seed vigor
Seed property that determines its potential for rapid uniform emergence and development under a wide range of field conditions.
seedbed
The bed on which rice seeds are sown, consisting of soil (wetbed method) or banana leaves, plastic sheets or concrete floor (dapog method).
seeder
A machine that plants the seed in the field. Small seeders are used for small experiments; very large seeders are used on large farms.
seedling
The stage of the plant after seed germination until the development of the fifth leaf.
Seedling stage
The period when a rice plant develops the first 5 leaves or so until tillers aredeveloped.
seepage
The lateral flow of water into or from a soil, as from a body of water into neighboring soil, or the reverse.
self-pollination
Pollination between the pollen and stigma within the same flower of the same plant.
seminal roots
Sparsely branched roots that replace the radicle and are later replaced by the adventitious roots.
senescence
The aging and drying of leaves and nonbearing tillers.
sensitive period
The plant's growing period when it is most affected by the prevailing environmental factors such as daylength and disease or insect attack.
sheath blight
A disease caused by the fungus Rhizoctonia solani / Thanatephorus cucumeris. The disease is characterized by ellipsoidal, necrotic lesions occurring initially at the leaf sheaths near the water line. Lesions may enlarge and spread on leaves and ultimately on panicles.
sheath rot
A fungal disease caused by Acrocylindrium oryzae. Rotting occurs on the uppermost leaf sheaths enclosing the young panicles. The lesions start as oblong or somewhat irregular spots, 0.5-1.5 cm long, with brown margins and gray centers, or they may be grayish brown throughout. Powdery growths may be found inside affected sheaths.
shoot
The vegetative parts (leaves, stem) of a plant above the ground level.
short-duration varieties
Varieties that mature in 120 days or less.
short-term crops
Varieties that mature within 105 days or less.
soak
To be completely covered by water for a determined length of time or until the object is saturated.
soil
The unconsolidated mineral matter on the surface of the earth that serves as a natural medium for growth of land plants. This has been subjected to and influenced by genetic environmental factors of parent material, climate (including moisture and temperature), macro- and microorganisms, and topography, all acting over a period of time and producing a product--soil--that differs from the material from which it is derived in many physical, chemical, biological, and morphological properties.
soil texture
The relative proportions of sand, silt, and clay particles in a soil.
soil tilth
The quality of soil, keeps it from packing together.
spikelet
The basic unit of the rice inflorescence consisting of the two sterile lemmas, therachilla, and the floret.
stamen
The part of the flower bearing the male reproductive cells; composed of the anthers on the filament (stalk).
starch
1). The major storage carbohydrate of plants; a polymer composed of D-glucose units occurring as amylopectin and amylose and found in chloroplasts, amyloplasts, and endosperm. 2). Major carbohydrate source for animals.
stem borer
An insect belonging to the order Lepidoptera that infects stems of rice. The adults of most stem borer species are nocturnal and are attracted to light, especially ultraviolet light. Deadhearts and whiteheads are two visible symptoms caused by stem borer larva infestation.
stem elongation stage
The increase in length of the 4th internode of short-duration varieties below the point where the panicle primordium emerges.
sterile
Failing to produce or incapable of producing offspring.
straw
The dry stems and leaves of a rice plant that have been harvested and discarded from threshing.
stress
The state or condition of injury caused by detrimental effects of environmental factors such as drought, excess water, temperature, and others.
stripper harvesting
A method of harvesting seed or leaf material where the seed or leaf is mechanically removed from plant in situ, usually by a comblike device.
stunting
Dwarfing due to disease or physiological disorder .
submergence (of plant).
A plant standing in water with at least part of the terminal above the water (partial submergence); or completely covered with water (complete submergence).
submergence tolerance
Ability of a rice plant to survive after being completely under water from a flash flood.
susceptible
Having little or no resistance to a specific infectious disease, insect pest, or other biological and physical stresses. When the host plant is unable to suppress or retard an injurious insect.
1). Bench-like portions of a former flat river floodplain left at higher levels by the downcutting action of a river; alluvial terraces and river terraces are generally considered as synonymous.2). An artificially leveled field or series of fields made on sloping land.
Tertiary tillers
Tillers arising from secondary tillers.
tillage
1). The mechanical alteration of some physical properties of the soil to provide a condition appropriate for crop growth. 2). To cultivate the land, to gain moisture in the soil.
tiller
A vegetative branch of the rice plant composed of roots, culm, and leaves which may or may not develop a panicle. Shoot arising from the main culm (stem).
tillering stage
Growth stage of the rice plant that extends from the appearance of the first tiller until the maximum tiller number is reached.
tilth
The physical condition of the soil as related to its ease of tillage, fitness as a seedbed, and its impedance to seeding emergence and root penetration.
tolerance
Ability of a plant to withstand stress without yield reduction or injury.
toxin
Any of the various poisonous substances produced by certain plants and animal cells including bacterial toxins, phytotoxins, and zootoxins.
traditional cultivars
Tall, weak-stemmed, long-duration, low-yielding cultivars grown by farmers for many years.
trait
A distinguishing quality or character of a plant.
transgenic
Descriptive of an organism that contains some genetic material that has been experimentally transferred into it from some other source.
translucency
The opposite of chalkiness; measured with a Riken-Sanno Rice Meter which measures transmitted light through a fixed volume of rice grains, one model for brown rice, another for milled rice.
transpiration
The process by which plants release water vapor to the atmosphere through surface pores (stomatal openings) in the plant foliage in response to atmospheric demand. The water of transpiration usually reaches a maximum value in the afternoon and a minimum value just before sunrise. Soil moisture content and plant characters, such as location and distribution of stomata, reduction of transpiration surface (leaf rolling), and plant age, affect transpiration rate.
trial
An experiment to determine or test the quality or performance of a specific variety, system, or crop rotation and its usefulness in increasing farmers' production.
tungro
A viral disease transmitted by green (Nephotettix spp.) and zigzag leafhoppers (Recilia dorsalis). The diseased plants are characterized by stunting and reduced tillering. The leaf color ranges from light yellow to orange-yellow. Yellowing usually starts from the tips of the leaves. The panicles are often not fully exserted. The grains are usually covered with dark brown blotches.
two-line breeding
Hybrid rice breeding methodology where only two lines, a male sterile (either photosensitive, thermosensitive, or chemically induced) and a pollen parent are used for the production of Fl hybrids.
Even; not varying; every factor has the same treatment.
upland field
A rainfed land area with no levees or dikes surrounding it to impound water; sowing is by direct seeding.
upland rice (dryland rice)
Rice grown on both level and sloping fields that are not bunded, that are prepared and seeded under dry conditions, and that depend on rainfall for moisture (without surface water accumulation).
1). A group of cultivated plants within a species which is distinguished from another variety (group) by any characters (morphologic, physiological, biochemical, or other) of significance to agriculture and which, when reproduced, retains its distinguishing characters. A variety may be derived from several pure lines which have many common features and are reasonably uniform in appearance (but not necessarily genetically pure). 2). A group of similar plants which, by structural features and performance, may be identified from other varieties (groups) in the same species. It differs from a breeding line in that it has been named and made commercially available to farmers. 3). A subdivision of a species; a group of individuals within a species which are distinct in form or function from other similar arrays of individuals in commercial production. Variety is synonymous with cultivar.
Vegetative phase
The period from seed germination to panicle initiation.
vegetative phase/stage
The period from seed germination to the panicle initiation stage.
vigor
1). Plants. To have active, healthy, well-balanced growth. 2). Seeds. The capacity for natural growth and survival.
virus
A submicroscopic infectious agent consisting of particles made up of DNA or RNA which are usually covered by protein and reproduce only in living cells; cannot be separated by filters.
To control the amount and depth of water in the ricefield during the required time necessary for crop growth.
water table
The upper surface of ground water and the level below it where the soil is saturated with water.
watershed
The total area from which a single river collects surface water runoff; the catchment or drainage area of a river system.
weed
Any unwanted plant that is injurious to the crop.
weed control
Prevention or eradication of weeds by physical removal (hand weeding) or limiting their growth by mechanical or chemical means.
weeding
Removing unwanted plants by hand from a crop, or tillage action which lightly cultivates the soil for the purpose of destroying the weeds.
weevil
The adult form of a certain coleopterous species.
wetbed method
Raising seedlings on a seedbed where land is prepared and puddled.
wetbed seeding
Planting of pregerminated seed or small seedlings into a wet seedbed.
wetland
1). Pertaining to soils flooded for at least several weeks each year, or to crops growing in such soils. 2). Land of which the rooting zone can be kept saturated for a substantial part of the growing season, where necessary, by encouraging accumulation of water on the soil through puddling and the use of bunds or levees.
wetland tillage
Preparing the soil by plowing of lowland fields and harrowing the soil in a saturated or flooded condition.
white tip
A disease of rice caused by the nematode Aphelencoides besseyi, with symptoms consisting of chlorosis of the leaf tips which become brownish and tattered. The infected plants are stunted and produce a few, small spikelets/panicles.
wild rice
Species of Oryza that are not cultivated.
wilt
A characteristic of the plant indicated by drooping, folding, rolling, or collapsing leaves due to an unfavorable water balance.
wilting
The loss of turgidity in plant tissue where the intake of water is insufficient to replace that lost by transpiration or other means, causing a deflation of the plant cells.
A viral disease transmitted by green leafhoppers (Nephotettix sp.). The first symptom of yellow dwarf is general chlorosis, especially on the newly emerged and young leaves. The color varies from yellowish to green. As the disease progresses, the infected plants become severely stunted, tillering increases markedly, and leaves become soft and droopy. The infected plants produce either no panicles or a few small panicles, which bear mostly unfilled spikelets.
yellow mottle
A disease caused by rice yellow mottle virus. The virus disease can be transmitted by mechanical inoculation or vectored by the adult beetle Sesselia pusilla. It is characterized by stunting and reduced tillering of the infected rice plant; crinkling, mottling, and yellowish streaking of the leaves; malformation and partial emergence of the panicles and sterility.
yield
The amount of a specified substance produced.
yield components
The factors that contribute to grain yield--number of panicles per square meter, spikelets per panicle, percentage of fertile spikelets, and weight of each single grain.
yield potential
The maximum grain yield of a given variety in a given environment without constraints involving water, nutrients, competition, pests, diseases, or climatic conditions.
A practice where planting or seeding is directly done in untilled land.
zinc deficiency
Insufficient zinc in the plant tissue causes the midribs of the young rice leaves to become chlorotic especially at the base, brown blotches and streaks occur in the lower leaves, growth is stunted, tillering is reduced, leaf blade size is reduced, and uneven growth occurs.