How a new grape variety is created

There are basically two ways in which a new variety can be created:

1. Mutations occur in an already known variety that are so strong that the mutated vine differs significantly from the original variety.
   For example, Pinot Noir gave rise to Pinot Blanc and Pinot Gris. These two varieties differ only in the colour of the berries.
2. The pistil of the vine flower is fertilised by pollen from another variety and the resulting seeds sprout and grow into a plant.
   Normally, however, this happens very rarely, as the vines usually fertilise themselves. This means that the pollen reaches the stigma directly in the flower and is thus fertilised.

When breeding new varieties, the second method is used almost exclusively. Below is a rough overview of the steps that take place one after the other. It is a complex and very lengthy process.

1. goal setting and planning

Firstly, the breeder determines which characteristics the new variety should have if possible, e.g. higher yields, better disease resistance, better wine quality or adaptation to certain climatic conditions.

These goals change over time. Until well into the 20th century, for example, the focus was on yield security (= higher yields). Today, sustainability is more in the foreground, so that disease resistance takes centre stage. Of course, other characteristics also have to be right. A resistant vine that produces no or poor-quality yields is not economically viable.

2. selection of parent plants

The selection of suitable parent plants is of crucial importance. These plants must have the desired characteristics. Resistant varieties are often crossed with varieties that have good fruit characteristics.

The parent plants are then selected according to the desired objectives. Until around the beginning of this century, only the phenotype (= appearance) could be used as a guide. We only knew from experience which variety inherited which trait well. However, this could be different for the next cross.

Since the genome of the first mildew-resistant grape variety, Regent, was decoded in 2009, genetic engineering has become increasingly established as an aid in breeding. So-called resistance loci can now be identified. These are specific sections on certain chromosomes that are responsible for certain resistances. Various resistance loci are now known, particularly for mildew species. Parents can therefore be selected according to the presence of these resistance loci.

3. crossing

Crossing is carried out by hand pollination.

To do this, the mother plant must first be freed of pollen (castrated). This is very time-consuming work, which is carried out with tweezers and requires a great deal of dexterity.

The pollen from the father plant is then collected. To do this, a plastic bag is usually simply placed over an inflorescence and the pollen is shaken into the plastic bag.

This plastic bag is then placed over the castrated flower in order to distribute the pollen to the stigmas of the individual flowers, again by shaking.

This produces seeds (= kernels) that contain the genetic information of both parent plants.

4. raising the seedlings.

When the grapes are ripe, the seeds of the pollinated berries are harvested and dried.

The seedlings resulting from the seeds are grown in a controlled environment and are often tested at this stage for the presence of certain characteristics.

When breeding mildew-resistant vines, for example, these young seedlings are immediately exposed to conditions that favour mildew. If the seedlings still grow, it can be assumed that resistance is present and more targeted selection can be carried out.

5. selection

Selection is a critical step. Here, the best seedlings that best combine the desired characteristics are selected. This selection can take several years and involves extensive testing for disease resistance, yield and quality.

With today's modern methods, it is possible to test for the known resistance loci at a very early stage. This can speed up resistance testing.

In addition, all other characteristics such as yield, quality and habit are also tested.

6. test cultivation

If a new variety fulfils the criteria to the desired extent, it is tested in lengthy trials. Its adaptability to different environmental conditions (climate, soil and weather) must now be tested in lengthy trials.

To this end, the selected seedlings are grown in different regions and under different conditions. This ensures that the new variety grows and thrives in more than just one location.

7 Testing and authorisation

After successful testing, the new variety is evaluated and often has to be authorised by official bodies. This includes testing for compliance with certain standards and registration of the variety.

8 Propagation and commercialisation

After approval, the new variety is propagated so that sufficient plant material is available for commercial cultivation. Finally, the variety is commercialised and made available to winegrowers.

Points 5 to 9 are sometimes carried out in parallel so that an interesting variety can be planted by winegrowers as quickly as possible.

The development of new grape varieties can take many years, often even decades. It requires close co-operation between breeders, scientists and winegrowers in order to be successful.