Crossbreeding

Crossbreeding (Cross-Breeding) [ Genetics ]	Dictionary of botanic terminology index of names
Synonym: Hybridization, Cross, Interbreding, Intercrossing.

The mating of animals or plants of different strains or species; Hybridization.

The term "Crossbreeding" principally refers to the reproduction between two distinct conspecific varieties (unrelated strains of a particular species) while "hybridization" (usually) refers to the reproduction between different species or higher taxa. But in the common use the distinction between the meaning of crossbreeding and hybridization is not so clean and the two term are from time to time used as synonyms.

Below: An example of crossbreed involving two different Astrophytum species (Astrophytum asterias x Astrophytum coahuilense) the resulting interspecific F1 hybrid shows intermediate characteristic from both the parents.

How to make plant crossbreedings: It is harder to give a general explanation about how to crossbreed, or hybridise, two different plants, because the details do vary from one organism to another. First it is necessary to take the pollen from the anther (male organs) of one plant and move it to the stigma, (female organ) of another, making sure that no other pollen apart from the one that is supplied can reach the stigma.

	In autosterile species, it is quite easy, the pollen can be collect (for example whit a small painting brush or with a pair of forceps) and then placed directly over the receptive stigma, after that the fecundated flower can be covered with a paper bag. Dioecious species are also quite easy, because the male and female flowers are separate. But autofertile species are much more difficult. In these plants, a single flower has both male and female parts. For this reason it is necessary to remove the male parts (emasculation) from the “mother” flower before adding the pollen from the “father”. The pollen may be transferred with a fine paintbrush.
After the cross has been made it is important to label the mother flower with the details, so that (when seeds will be harvested) it will be possible to know which parents were used. Crossbreeding usually results in heterosis (hybrid vigour). For more details see: Hybridization

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994