At a crossing or. breeding from varieties the parents are usually in the form of "New variety = mother variety x fathers" specified (see an extensive listing under the keyword new breed ). For example " Müller-Thurgau = Riesling (Mother) x Madeleine Royale (Father)". This is also referred to as crossing direction. This is important because much more cell material is transmitted from the parent to the embryos in the seeds, namely, nucleus, plastids and mitochondria. By contrast, only the cell nucleus is passed on from the father's place (see also detailed under blossom ).
The mitochondria are cell areas with energy producing functions and their own DNA (Deoxyribonucleinacid, genetic material). The chloroplasts belong to the group of plastids. They have their own ribosomes (for the production of proteins) compared to the other parts of the plant and, like mitochondria, also have their own DNA. This allows them to share regardless of the cell in which they live. Other plastids are amyloplastics (storage of starch), chromoplasts (attracting insects for the purpose of pollen dispersal for pollination) and leucoplasts (chemical defense against predators).
Only by DNA analysis of the passed through the mother's chloroplasts, the crossing direction can be determined. For many varieties, but something has not been done. Sometimes the differences are not sufficient to be able to determine exactly the direction of intersection. This was successfully done, for example, with the variety Cabernet Sauvignon ( Sauvignon Blanc = Mother variety x Cabernet Franc = Fathers) and at most crossings Pinot x Gouais blanc (or the other way around). For many other varieties, this has just not happened, so the information should be considered with caution.
Photos: Ursula Bruehl, Doris Schneider, Julius Kühn Institute (JKI), Federal Research Center for Cultivated Plants,
Institute for Grapevine Breeding Geilweilerhof - 76833 Siebeldingen, GERMANY