Selection of New Grape Varieties and Clones

Question 1

Ampelographic platform

Answer 1

identify and propagate only the best vines

Question 2

Productive hybrids

Answer 2

breeding for resistance

Question 3

Main goals for grapevine breeding

Answer 3

resistance to fungi, pest, virus, nematodes, bacteria; resistance to freezing, frost, drought; fruit quality; regular productivity; improve tolerance to BSN, chlorosis…; other agronomic issues

Question 4

Role of breeding

Answer 4

increase variability in populations; selection of new genotypes with improved adaptability; rediscover, protect and create biodiversity; provide new material allowing adaptation to market evolution

Question 5

Grapevine breeding methods (traditional)

Answer 5

mass selection; clonal selection; intraspecific crossbreeds; interspecific crossbreeds

Question 6

grapevine breeding methods (innovative)

Answer 6

assisted selection (cell and tissue ‘in vitro’ culture); protoplast fusion; somaclonal variation; gene transfer (transgenesis and cisgenesis)

Question 7

Intra-varietal variability

Answer 7

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

Question 8

Causes of genetic variability

Answer 8

Polyclonal origin of grapevine varieties; long term accumulation of genetic mutations

Question 9

Somatic mutations

Answer 9

a main source of diversity within a grapevine variety (in a given bud, mutations affect genetic makeup of meristem cells)

Question 10

Source of somatic variation

Answer 10

viruses, ionizing radiation, thermal shock or mechanical trauma; physical and chemical mutagens

Question 11

Factors influencing levels of intravarietal variability

Answer 11

time span (during which grape variety was developed); spatial diffusion… the longer the variety has been cultivated, and more diffusion over different regions it experiences, will grow the intravarietal variability

Question 12

Ancient origin

Answer 12

varieties grown over long period of time

Question 13

Recent origin

Answer 13

varieties more recently planted

Question 14

Mass selection

Answer 14

identification of grapevines (by empiric method: direct or indirect observation) from which collect scions for propagation

Question 15

Scion

Answer 15

a young shoot or twig of plant

Question 16

Positive mass selection

Answer 16

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

Question 17

Negative mass selection

Answer 17

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

Question 18

Clonal selection aims to…

Answer 18

identify; verify; check health status; propagate

Question 18

Selective pressure (high)

Answer 18

clones with high adaptability to different environment and wine styles; combination of several positive characters in a single individual not easy to achieve; because positive and negative characters are frequently associated, many individuals are excluded; as a cause of genetic erosion, dramatically reduces the intravarietal variability of genotypes subjected to clonal selection

Question 18

Check the health status (clonal selection aims)

Answer 18

of mother-plant-derived material before propagation

Question 19

Identify (clonal selection aims)

Answer 19

healthy grapevines showing improved agronomical and/or enological traits as compared to average of variety

Question 19

Timeline for new clone

Answer 19

at least 13 years, in general 15 years are required to obtain a new clone

Question 19

Selective pressure (low)

Answer 19

aims to preserve morphological and functional variability of varieties subjected to clonal selection; protection of minor traits are difficult to determine (anthocyanin and aroma profiles); reduces interaction between genotype and environment (higher stability in different environments over years)

Question 20

Clonal selection

Answer 20

“Population of vines all derived by vegetative propagation from cutings or buds from a single mother-vine by deliberate clonal selection”; only recognized way to obtain clones

Question 20

Verify (clonal selection aims)

Answer 20

stability and genetic basis of such characteristics by mid-to-long term assessment

Question 20

Propagate (clonal selection aims)

Answer 20

healthy and homogeneous selected material for establishing new commercial vineyards

Question 21

genetic variation compared to biodiversity

Answer 21

always a negative correlation (only promoting plants with attractive qualities to US, removing those that have unattractive qualities; therefore, decreasing the amount of intravariety variability)