Designation for a generative, i.e. sexual reproduction with parenthood of at least two different grape varieties, as is the case, for example, with the new breeding of grape varieties One variety acts as a mother plant, from which the berries ripen with the fertilised seeds, while the other variety, as the father variety, provides the pollen for pollination of the scars and fertilisation of the maternal seed systems (see also detailed information under Flowering and Hermaphrodites). Since the mid-1990s, it has become a worldwide standard to determine the parentage of grape varieties by DNA analysis. It is also possible to determine the crossing direction (who was the mother variety, who was the father variety). When crossing parents are indicated, the mother variety is always mentioned first in the breeding lists. Four new breeds:
From the fertilized seminal plants, descendants result which, according to the laws of heredity discovered by Gregor Mendel (1822-1884), (ex half each) have the randomly recombined characteristics of both parents. In contrast to spontaneously occurring mutations which lead to the development of slightly different grape variety clones, somatic chimeras and grape variety variants, sexual reproduction always requires two parent varieties, whose cross-breeding products, the seedlings, each have an individual genotype with new characteristics. These are often used for further crosses. Four classic grape varieties from (most likely) natural crosses are
A new vine variety is usually created by cross-pollination with pollen from another vine variety (although there are also crosses between different clones of the same variety). A female flower bud of variety A is pollinated with the male pollen of variety B. In viticulture, only interspecific and intergeneric crosses are called hybrids, although strictly speaking this is also the case for intraspecific ones. The three possibilities:
The crossing of two grape varieties (cross-breeding) is one of the possible breeding methods besides selection breeding (clone selection or also clone breeding) and mutation breeding (artificial generation of mutants by mutagenic substances) - see in detail under breeding. In contrast, manipulative genetic engineering, in which desired characteristics such as resistance to fungal diseases or frost are achieved by genetic modification of the genetic material. For more information on this topic, see Parent-Offspring Relationship and Vine Systematics as well as a complete list of relevant keywords on grapevine varieties under Grapevine.
Pictures: Ursula Brühl, Doris Schneider, Julius Kühn Institute (JKI)