Dredging

An operation to remove the accumulated silt in a dam.

Dibbling:

System of placing the seed in the soil by hand.

Defoculation

Action to separate or break down soil aggregates of clay into their individual particles.

Damping-off :

Death of seedling caused ty the attack of somePyhium spp. This normally occur under high condition and over crowding of seedlings.�

Desiccate

The process of drying of any object so as the moisture fall below the normal level.

waxy corn

Rice with 0-2% amylose or mainly amylopectin in the endosperm and pollen starch.

wetland plants

Plants adapted for survival in soils frequently saturated with surface or groundwater.

wheat allergy

A malabsorption syndrome that is precipitated by the ingestion of foods containing gluten, such as wheat, rye, and barley. It is characterized by inflammation of the small intestine, loss of microvilli structure, failed intestinal absorption, and malnutrition.

white tea

Tea made from the dried leaves and buds of the Camellia sinensis plant.

whole farm planning

An approach to farm management which addresses environmental considerations within the farm enterprise, such as water supply, waste management, runoff, etc. Best management practices may also be considered in the whole farm plan for sustainability of farm operations.

wide hybridization

interspecific and intergeneric hybridization which is a first step to introduce alien variation and to transfer desirable genes and traits from wild species into cultivated species

white-rot fungi

A group of decay fungi that are able to degrade cellulose, hemicellulose and lignin in wood. Compare with brown rot fungi.

wines

All alcoholic beverages made from the fermentation of grape juice, other fruits or vegetative parts. Wine may be sparkling or carbonated, made from condensed grape must, made from agricultural products other than the juice of grapes, and includes products sold as wine such as imitation wine, cider and sake

yield tables

A table showing, for one or more species in a fully stocked stand, the growth pattern of a managed even-aged stand derived from measurements at regular intervals covering its useful life. It includes mean d.b.h. and height, number of stems, and standing volume per unit area. The table may also contain a variety of other useful data

Z-DNA

A less common "zig-zag" conformation of double-stranded DNA with a left-handed double helix which requires alternating GC sequences. It is favored by high salt concentration, but may occur in cells and may have regulatory functions

zearalenone

(S-(E))-3,4,5,6,8,10-Hexahydro-14,16-dihydroxy-3-methyl-1H-2-benzoxacyclotetradecin-1,7(8H)-dione. One of a group of compounds known under the general designation of resorcylic acid lactones. Cis, trans, dextro and levo forms have been isolated from the fungus Gibberella zeae (formerly Fusarium graminearum). They have estrogenic activity, cause toxicity in livestock as feed contaminant, and have been used as anabolic or estrogen substitutes.

zein

A group of alcohol soluble seed storage proteins from protein bodies in endoplasmic reticulum of corn endosperm

zero wastes

Waste management objective in which industrial outputs are reused as inputs and products are recycled to eliminate waste

zinc finger motif

Motifs in DNA- and RNA-binding proteins whose amino acids are folded into a single structural unit around a zinc atom. In the classic zinc finger, one zinc atom is bound to two cysteines and two histidines. In between the cysteines and histidines are 12 residues which form a DNA binding fingertip. By variations in the composition of the sequences in the fingertip and the number and spacing of tandem repeats of the motif, zinc fingers can form a large number of different sequence specific binding sites.

zero emissions

Pollution abatement objective in which industrial processes or energy source emissions contribute no waste products, such as greenhouse gases, that pollute the environment or effect climate change; actual emissions may be offset through recycling, carbon sequestration or environmental credit trading