Acronyms and Glossary of Rice Related Terminology Updated November 27, 2002

F Terms

Fl. Abbreviation for the first filial generation, usually the hybrid between two homozygous types.

FCC. fertility capability classification; a classification based on quantitative topsoil and subsoil parameters directly relevant to plant growth; various soil condition 'modifiers' define specific types of soil adversity or complexes of edaphic problems.

F layer. A soil layer of partially decomposed litter with portions of plant structures still recognizable. Occurs below the L layer (O11 horizon) on the forest floor in forest soils.

F test. A test of statistical significance consisting of the ratio of two independent variances of normally distributed variables.

Fl hybrid. Denotes the first generation offspring from the mating of two parents.

F2. The second filial generation obtained by self-fertilization of F1 individuals.

F2 population. Population of individuals present in the F2 generation of a cross.

F2 ratio. The segregation pattern of a character or characters in F2 generation.

F2 seed. The second generation progeny from the mating of two parents.

F3. Progeny obtained by self-fertilizing F2 individuals.

factorial. Where two or more treatments of an experiment produce different interactions.

factorial experiment. An experiment where treatments are combinations of two or more factors. The treatments can be either complete factorial combinations or incomplete factorial combinations.

facultative saprophyte. An organism living on another living organism during part of its life cycle or living on the dead tissues of its host.

fadama. Naturally flooded plains in Nigeria where rice grows.

Fahrenheit (oF) A temperature scale in which the freezing point of water is taken as 32 °F and the boiling point of water as 212 °F (or 100 °C) under standard atmospheric pressure.

fallow. Land that is ordinarily used for crops but allowed to lie idle between crops.

false smut. A disease caused by Ustilaginoidea virens. The fungus transforms individual grains of the panicle into greenish spore balls that have a velvety appearance. The spore balls are small at first and enclose the floral parts. They are covered with a membrane which bursts as a result of further growth and the color of the ball becomes orange and later yellowish green or greenish black. (Also known as grain smut)

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.

feeding lesion. A damaged area on a plant part resulting from the feeding of an insect.

female flower. A flower with functional ovary but no stamens.

female parent. The parent which contributes its egg in a cross. The plant with the ovary, style, and stigma that may produce fruits or seeds.

fermentation. Any of the chemical reactions induced by living or nonliving agents that split complex organic compounds into relatively simple substances, e.g., the anaerobic conversion of sugar to carbon dioxide and alcohol by yeast.

ferrolysis. A soil-forming process resulting in acidification and clay destruction due to alternating reduction and oxidation in practically flooded soils.

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.

fertility (genetics). The ability to produce viable offspring.

fertility (soil). The status of a soil with respect to its ability to supply nutrients essential to plant growth.

fertilization (genetics). Fusion of the nuclei of male and female gametes. The union of the pollen (male) and the egg (female) initiating reproduction.

fertilization (soil). Making soil fertile with the application of fertilizer.

fertilizer. Any substance added to the soil to supplement elements required in the nutrition of plants.

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.

fertilizer response function. A function that relates yield (output per hectare) to the amount of fertilizer used (input per hectare), holding all other inputs constant.

fertilizer, starter. A relatively small application of fertilizer applied with or near the seed for accelerating early growth of the crop.

fertilizer grade. The guaranteed minimum analysis of the major plant nutrient elements contained in a fertilizer material. It is expressed in percentage of N, P₂O₅, and K₂O.

fertilizer ration. The relative amount of N, P₂0₅, and K₂0 in a fertilizer grade.

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 responsiveness. The ability of the plant to utilize the applied fertilizer.

fibrous. Thread-like.

fibrous root system. Adventitious roots from the base or stem of the rice plant that form the mat roots.

field capacity. The amount of water remaining in a field soil that has been thoroughly wetted and drained until free drainage has practically ceased. The soil can no longer absorb additional moisture.

field. Cultivated open land area; land used for raising crops or for conducting experiments.

field collecting. The collection of samples from the field.

field resistance. Resistance observed in the field as distinguished from resistance observed in the laboratory or greenhouse. It may involve seedling resistance as well as adult plant resistance and often involves resistance to all locally occurring biotypes.

field sampling. 1). Fields may be chosen randomly for sampling from a map locating the coordinates and the cultivator interviewed. Samples are then taken according to the plan. 2). A field is divided into particular proportions and a grid is used for even sampling of different sections of the field.

field screening. Evaluating varieties for resistance in the field in contrast to greenhouse and screenhouse evaluations.

filament. In a flower, the slender stalk of the stamen.

filial generations. Generation after making a cross. Refer to offsprings resulting from a cross of parents, as in F1 (first filial generation), F2 (second filial generation), etc.

filled grain. A seed with a fully developed endosperm.

filler. 1). A material that does not contain any fertilizer element but is added to obtain the desired weight of a mixed fertilizer. 2). Rice variety used to fill vacant areas of an experimental plot.

filter paper. Porous paper used for filtering liquids.

film water. A layer of water surrounding soil particles and varying in thickness from 1 or 2 to perhaps 100 or more molecular layers. Usually considered as that water remaining after drainage has occurred because it is not distinguishable in saturated soil in rice production (puddled soils).

fine stripe (fs). Seedlings show fine greenish white longitudinal stripes at tip and margin of leaf blade. Stripes often disappear in the tillering stage.

fine texture. Consisting of or containing large quantities of fine fractions, particularly of silt and clay.

fire, ground. A fire that consumes organic material and burns into the underlying soil itself, for example, a peat fire. Applies in some deepwater rice areas of southern Vietnam.

firm. A term describing the consistency of a moist soil that offers distinctly noticeable resistance to crushing but can be crushed with moderate pressure between the thumb and forefinger.

fixation. The process by which certain nutrient elements in a soil are converted from available form to unavailable form essential for plant growth, being converted from a soluble or exchangeable form to a much less soluble or to a nonexchangeable form. Examples are potassium, ammonium, and phosphorus fixation.

fixation, nitrogen. Conversion of available nitrogen to insoluble or unavailable nitrogen.

fixative. A preservative or chemical used to keep plants for subsequent study.

fixed ammonium. The ammonium in soil that cannot be replaced by a neutral potassium salt solution.

fixed line. A breeding line that continues to breed true to type and does not segregate.

fixed phosphorus. That phosphorus which has been changed to an unavailable form as a result of reaction with the soil.

flaccid. Limp and flabby.

flag leaf. The uppermost leaf originating just below the panicle base.

flagellum. A thread-, hair-, or whiplike structure that serves to propel a motile cell.

flat planting. A method of planting in which the seed is planted on harrowed, dragged, or plowed flat land with a planter that causes minimum disturbance to the smooth surface.

flash flood. A rapid surge of flooding that subsides after several days and lasts no longer than 10-12 days.

flat land. Low-lying flat areas or a plain where rice grows.

fleshy. Thick and soft.

flavor. The taste and smell of particular rice varieties.

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.

flood plain. The land bordering a stream or river, built up of sediments from the overflow of the stream or river and subject to inundation at the peak of the flood period.

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 small flower, generally one of a dense cluster but an individual flower in members of families Poacea and Asteracea.

flowable (F). A formulation which consists of a pesticide plus dust diluent that is blended in a small quantity of water.

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.

flowering date. The date recorded when the panicles emerge from the boot.

fluctuation. A wavering, unsteady, irresolute, or undetermined movement or pattern; irregular rising and falling.

fluorescence. The property of emitting electromagnetic radiation usually as visible light resulting from external stimulation with another light (or energy) source and occurring only during the absorption of radiation from some other source.

flush. A short, quick watering period; a sudden growth burst.

flux. Rate of transfer of a quantity (water, heat, etc.) across a surface.

fluxial. Pertaining to flooding by surface water conveyed from elsewhere.

flux density. Flux across a unit cross-sectional area.

fluxic. Derived from the flux or passing through. Descriptive of a wet land type where free water remains in the field when the soil has been puddled, but the depletion rate of free water, including evapotranspiration losses, is more than 10 mm/day.

foliar. Referring to leaves of a plant; application of chemicals to the leaves.

foliar diagnosis. An estimation of mineral nutrient deficiencies (excesses) of plants based on examination of the chemical composition of leaves and the color and growth characteristics of the foliage of the plants.

formulation. Mixture of a pesticide with diluents, solvents, wetting agents, or other inert ingredients which can be used in pest control.

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.

FPLI (Functional Plant Loss Index). A formula based on the plant weight loss and damaged ratings due to insect feeding which is used in determining levels of tolerance when identifying components of resistance.

fracture. Random breakage that results in fragments of unpredictable shape.

fritted trace elements. Sintered silicates having total guaranteed analyses of micronutrients with controlled (relatively slow) release characteristics.

fruit. The ripened (mature) ovary containing one or more seeds.

full sibs. Individuals derived from the same parents.

fumigant. Highly volatile chemical that kills mice, insect, weeds, and other living organisms.

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.

furrow. A trench or long narrow cut in the soil after a plow passes through it, a trench or ditch dug by hand.

furrow slice. The ribbon of soil cut, lifted, pulverized, thrown, or turned to one side by the plow bottom.

fusion. Union of two broken fragments.

fuzzy hull (Hg or Lh). Long, smooth, dense hairs on the hull resulting in a fuzzy appearance; probably synonymous with shaggy hull.