Plant breeding

Plant breeding is the art and science of changing the traits of plants in order to produce desired characteristics. Plant breeding can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to more complex molecular techniques (see cultigen and cultivar).

Plant breeding has been practiced for thousands of years, since near the beginning of human civilization. It is practiced worldwide by individuals such as gardeners and farmers, or by professional plant breeders employed by organizations such as government institutions, universities, crop-specific industry associations or research centers.

International development agencies believe that breeding new crops is important for ensuring food security by developing new varieties that are higher-yielding, resistant to pests and diseases, drought-resistant or regionally adapted to different environments and growing conditions.

History

Plant breeding started with sedentary agriculture and particularly the domestication of the first agricultural plants, a practice which is estimated to date back 9,000 to 11,000 years. Initially early farmers simply selected food plants with particular desirable characteristics, and employed these as progenitors for subsequent generations, resulting in an accumulation of valuable traits over time.

Crossing

Crossing may refer to:

Entertainment

Other

See also

Crossing (2008 film)

Crossing (also known as Keurosing) is a 2008 South Korean film directed by Kim Tae-kyun. It has been selected as South Korea's submission to the 81st Academy Awards for Best Foreign Language Film. The film follows the journey of a North Korean man as he illegally leaves the country to find medicine for his sick wife, portraying the many hardships of the average North Korean citizen. The film had 907,255 admissions in South Korea.

The politics of North Korea in this film are left behind and are mainly in the background. Instead it concentrates more on the life of the average North Korean, such as the hardship in an impoverished state and the fear of getting caught and being persecuted in North Korea. Subtle themes include religion, which runs through the film, as Yong Soo hopes that his son comes back safely, as well as football which is a way in connecting the North Koreans to the outside world.

Plot

The story tells of a North Korean father and husband who decides to illegally cross into China to buy medicine for his pregnant wife who is suffering from tuberculosis. However, once he crosses into China, he realises that it's not as easy as he thought. He finds himself working as an illegal immigrant under the constant threat of being captured by the Chinese authorities and deported back to North Korea. He eventually finds his way to South Korea by entering the German embassy in China. Meanwhile, his wife has already died, leaving their son homeless and wandering around trying to find a way back to his father. Scenes switch between those of the father who is outside North Korea trying to find medicine, and those of the son, who ends up homeless and tries to defect also.

Knot theory

In topology, knot theory is the study of mathematical knots. While inspired by knots which appear in daily life in shoelaces and rope, a mathematician's knot differs in that the ends are joined together so that it cannot be undone. In mathematical language, a knot is an embedding of a circle in 3-dimensional Euclidean space, R³ (in topology, a circle isn't bound to the classical geometric concept, but to all of its homeomorphisms). Two mathematical knots are equivalent if one can be transformed into the other via a deformation of R³ upon itself (known as an ambient isotopy); these transformations correspond to manipulations of a knotted string that do not involve cutting the string or passing the string through itself.

Knots can be described in various ways. Given a method of description, however, there may be more than one description that represents the same knot. For example, a common method of describing a knot is a planar diagram called a knot diagram. Any given knot can be drawn in many different ways using a knot diagram. Therefore, a fundamental problem in knot theory is determining when two descriptions represent the same knot.

Plant

Plants, also called green plants, are multicellular eukaryotes of the kingdom Plantae. They form an unranked clade Viridiplantae (Latin for green plants) that includes the flowering plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants excludes the red and brown algae, the fungi, archaea, bacteria and animals.

Green plants have cell walls with cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts, derived from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are also characterized by sexual reproduction, modular and indeterminate growth, and an alternation of generations, although asexual reproduction is also common.

Precise numbers are difficult to determine, but as of 2010, there are thought to be 300–315 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants (see the table below). Green plants provide most of the world's molecular oxygen and are the basis of most of the earth's ecologies, especially on land. Plants that produce grains, fruits and vegetables form mankind's basic foodstuffs, and have been domesticated for millennia. Plants are used as ornaments and, until recently and in great variety, they have served as the source of most medicines and drugs. The scientific study of plants is known as botany, a branch of biology.

Plantà

The plantá (which comes from the verb to plant; in Valencian, plantà) is the act of erecting a Falla or bonfire monument, in the Fallas or the Bonfires of Saint John, festivals held respectively in March and June in different localities of the Community of Valencia (Spain).The plantà is currently considered the exact moment when the falla or bonfire is completely finished and ready to be visited, with all its “ninots” (human figures made of combustible materials, such as cardboard or wood, which has a critical or mocking nature), posters and a variety of features (lights, matted grass, interpretive signs...).

In the Fallas of Valencia, the plantá takes place on March 15, when all the Falla monuments must be positioned correctly. The reason is that the jury appointed by the Central Fallera committee has to go to the next day to assess the falla. Formerly, the plantà began and ended the same day but, due to the complexity of the monuments and the fact that the makers of Fallas are responsible for several Fallas monuments at the same time, it usually begins a few days before. The burning of the Falla or cremá is carried out four days later, on the night of March 19.

Plant (disambiguation)

A plant is a living organism that generally does not move and absorbs nutrients from its surroundings.

Plant may also refer to:

In manufacturing and engineering

In media and entertainment

In names