Selection of New Grape Varieties and Clones

Question 1

Background of grapevine breeding

Answer 1

Breeding takes origin when humans selected seedlings (including those spontaneously grown in forests) and then over a thousand years growers worked to identify and propagate only the best vines.

Question 2

Role of Phylloxera and grapevine breeding

Answer 2

When phylloxera colonized Europe grapevine breeding was extended to intraspecific hybrids. Utilizing the first rootstocks that were resistant to Phylloxera (American)

Question 3

How were productive hybrids created

Answer 3

When breeders tried to combine resistance to phylloxera with new resistance traits found in other american rootstocks such as resistance to powdery and downy mildew, while also maintaining vitis vinifera quality

Question 4

6 main goals of grapevine breeding

Answer 4

1. Resistance to Fungi, Pest, bacteria, viruses, and nematodes.
2. Resistance to frost, freezing and drought
3. Fruit Quality
4. Regular productivity
5. Improve tolerance to BSN, Chlorosis
6. other agronomic issues

Question 5

The four Roles of Breeding

Answer 5

1. Increase variability in populations
2. Selection of new genotypes with improved adaptability
3. Rediscover, protect, and create biodiversity
4. Provide new material allowing adaptation to market evolution

Question 6

How long does take for grapevine breeding methods

Answer 6

They require at least 10 years

Question 7

Two types of grapevine breeding methods

Answer 7

1. Traditional
2. Innovative

Question 8

Four types of breeding associated with the Traditional method

Answer 8

1. Mass Selection (Intra-varietal Variability)
2. Clonal Selection (Intra-varietal Variability)
3. Intraspecific Crossbreeds (Same Species)
4. Interspecific Hybrids (Different Species)

Question 9

Four types of Breeding associated with the Innovative Method

Answer 9

1. Assisted Selection (Cell and Tissue in Vitro Culture)
2. Protoplast Fusion
3. Somaclonal Variation
4. Gene Transfer (Transgenesis and Cisgenesis)

Question 10

What is Intra-varietal variability?

Answer 10

It is the genetic variability within a varietal. Breeding methods such as Clonal Selection and Mass Selection, that are driven by genetic variability that can rise within grapevine varieties

Question 11

2 factors that genetic variability is caused by

Answer 11

1. Polyclonal origin of grapevine varieties
2. Long term accumulation of genetic mutations

Question 12

Discuss the polyclonal origin of grapevine varieties

Answer 12

Intra-varietal variability is related to the presence of many genotypes within a grapevine variety. within the population of a given cultivar a certain number of individuals with different genetic makeup as compared to the true type can be identified.

Question 13

What are somatic mutations

Answer 13

They are one of the main sources of diversity within a grapevine variety. Somatic cells are non reproductive cells. Sources of Somatic mutations can be from viruses, thermal shock, mechanical trauma, or from physical or chemical mutagens). An example is Pinot Noir to Pinot Gris to Pinot Blanc

Question 14

All cultivars show different levels of intravarietal variability that is mainly related to two factors:

Answer 14

1. Time Span during which a grape variety was deleloped
2. Spatial Diffusion

Question 15

What is Mass Selection and what are the two types

Answer 15

Mass Selection is the identification by and empiric method of grapevines in order to collect specific scions for propagation. There are Positive and Negative.

Question 16

What is a scion?

Answer 16

a young shoot or twig of a plant, especially one cut for grafting or rooting.

Question 17

What is positive Mass Selection

Answer 17

Positive Mass Selection is the identification of grapevines showing positive traits concerning growth and productivity; tagged vines will be the only one where buds will be collected

Question 18

What is negative mass selection

Answer 18

Negative Mass Selection is the identification of grapevines showing negative traits concerning growth and productivity; they will be tagged and excluded during the bud sampling process

Question 19

Discuss the relationship between positive and negative mass selection and how they are correlated. (3 Points)

Answer 19

1. Positive mass selection pushes genetic progress
2. Negative mass selection allows for a higher concentration and higher biodiversity.
3. They are negatively correlated (Genetic progress goes down as biodiversity goes up.)

Question 20

Clonal Selection when obtaining clones

Answer 20

Clonal Selection is the only way to obtain clones

Question 21

What is a clone

Answer 21

A population of individuals obtained by vegetative propagation of just one individual isolated within a variety

Question 22

Four aims of Clonal Selection performed within a grapevine population of the same variety.

Answer 22

1. Identify healthy grapevines showing improved traits
2. Verify stability and genetic basis of improved traits for a mid - to- long term assessment.
3. Check the health status of the material from the mother-plant before propagation
4. Propagate healthy and homogeneous selected material for establishing new commercial vineyards.

Question 23

2 types of Selective pressure

Answer 23

High and Low

Question 24

Four Considerations of High selective pressure

Answer 24

1. Clones with high adaptability to different environments and wine styles
2. Combination of several positive characters in a single individual is not easy to achieve
3. Because positive and negative characters are frequently associated, many individuals are excluded
4. Due to genetic erosion, there is a dramatic reduction in the intravarietal variability of genotypes that are subjected to clonal selection

Question 25

Three aims of Low Selective pressure

Answer 25

1. Preserve the morphological and functional variability of varieties subjected to clonal selection.
2. Protection of minor traits are difficult to determine
3. Reduce the interaction between genotype and environment