General

Question 1

What is spring frost and why does it occur?

Answer 1

Spring frosts occur when cold air below 0°C collects at ground level, freezing any water vapour that has settled on the ground or the vine. If this happens to newly burst buds or young shoots; it kills them.
There are four main forms of protection:
1- Heaters
The heat they generate creates movement in the air preventing the cold air from settling and causing the frost.
2- Wind machines
The most commonly used looks like a large fan that draws warm air from above to keep the temperature at ground level above freezing. Some wind machines incorporate heaters.
3- Sprinklers may be used to spray water onto the vines.
As the water freezes, it releases some heat into the plant tissue protecting the buds and shoots.
4- Thoughtful vineyard design
Because cold air sinks to the lowest point it can find, it is best to plant vineyards on slopes and avoid depressions in which cold air can collect.
Vineyards planted on the middle of the slope are noticeably less at risk from frost damage than those in lower lying areas. Vines can also be trained high to avoid the worst of the cold air.

Question 2

Give an example of a grape variety mutation that the resulting plant is treated as a new variety.

Answer 2

Pinot Blanc and Pinot Gri are both mutations of Pinot Noir

Question 3

Give an example of a crossing : 2 parents of the same species – new variety.

Answer 3

Cabernet Sauvignon is a crossing of Cabernet Franc and Sauvignon Blanc.

Question 4

Giver an example of a crossing that were bred by researchers.

Answer 4

Müller Thurgau : Riesling and Madeleine Royale

Pinotage : Pinot Noir and Cinsault

Question 5

What is the difference btw crossing and hybrid?

Answer 5

Crossing : parents from same vine species (CS)

Hybrid: parents from different vine species

Question 6

What is the benefitof head grafting?

Answer 6

1- allows the grower to adjust quickly to the changes ib market demand. (new variety at next vintage, min 3 yrs to be able to produce a commercial crop)
2- cheaper than replanting the whole vineyard (you will have already established root system)

Question 7

What are the 5 things that the vine need?

Answer 7

heat
sunlight
carbondioxide
water
nutrients

Question 8

What can be done to protect the vines from hail?

Answer 8

netting
but this is costy.
This is done in Mendoza Argentina.
Hail stormstend to bevery localised, so the best protection maybe to reduce the risk of losing the whole crop by owning several ineyard sites in different locations.