Frequently Asked Questions

From IGGP

Contents 1 Taxonomy 2 Genome 3 Genetics 4 Breeding and Reproductive Biology 5 Plant Growth 6 Industry Statistics

Taxonomy

1. The Vitaceae (grape family) consists of many diverse species which grow in a range of climates. The species Vitis vinifera from the Vitis genus is the major cultivated grape crop.

Genome

1. The 1C genome size of Vitis vinifera is relatively small, approximately 480 Mbp.
2. The genome is diploid, though tetraploid and triploid plants have been produced.
3. Chromosome number is 2n = 38 for species in the Vitis genus.
4. Chromosome number is 2n = 40 for species like Muscadinia rotundifolia which is also known as Vitis rotundifolia.
5. BAC libraries, cDNA libraries, microsatellite markers, EST sequences and drafts of the genome sequence are available.
6. Vitaceae DNA and protein sequences held in GenBank public databases.

Genetics

1. The main cultivated species Vitis vinifera is of euroasian origin. It is known for the quality of its grape berries but it is susceptible to many pests and diseases.
2. Non-vinifera species in North America have many desirable traits including resistance to pests and diseases.
3. The genetics of many traits are unknown.
4. Populations for genetic mapping and germplasm collections holding unique genotypes are available.

Breeding and Reproductive Biology

1. Grapevine cultivars are highly heterozygous and inbreeding depression has been reported to be common.
2. Seedlings can take three years or longer to produce fruit under normal vineyard management conditions.
3. Flowering and fruit ripening in the vineyard is a long process. For example, in the Southern Hemisphere the inflorescences initiated in latent buds during October-December 2000 will flower and set fruit in September-October 2001 with fruit ready for harvest in March-May 2002.
4. Cultivated Vitis vinifera varieties produce hermaphroditic flowers. Wild-type vines are dioecious and have either male or female flowers.
5. The release of a new wine grape variety can take 20 years or longer from seed to commercialisation due to the need for extensive field trials and wine evaluation.
6. Biolistic and Agrobacterium transformation systems exist for a number species including V. vinifera. Wine and table grape cultivars have been transformed including; Sultana, Chardonnay, Cabernet Sauvignon, Shiraz, Reisling and others.
7. Field trials of transgenic vines are in progress in Europe and non-European countries.

Plant Growth

1. The plant is a perennial deciduous woody vine with a unique shoot architecture.
2. The non-climacteric, fleshy fruit has novel secondary metabolism producing colour pigments, tannins, flavour and aroma compounds.
3. Grapevine cultivars are clonally propagated by vegetative cuttings.
4. Cuttings planted under normal vineyard management conditions usually produce fruit suitable for harvest in the third year with full production in six years.
5. Grapevines grow well under glasshouse conditons but floral induction and fruit production is often poor.

Industry Statistics

1. Considered to be the world's major horticultural crop. Wine, fruit juice, fresh fruit and dried fruit are the main products.
2. Hectares in the world under grapevine cultivation in 2000 was 7.7 million hectares.
3. World grape production in 2000 was 64,029,460 Mt.
4. World wine production in 1999 was 28118 million litres.
5. A useful source of agriculture statistics are the FAOSTAT databases. For wine statistics go to the Australian Wine and Brandy Corporation site or the International Organisation of Vine and Wine.