Biodiversity
An introduction to biodiversity.
A simple explanation of what biodiversity is, how we make sense of it and its importance to us. Plus an introduction to the biodiversity of potatoes and tomatoes.
San Marzano
Unripe San Marzano tomatoes
Photographer: unertlkm. Copyright: CC
Cultivar: San Marzano
Species: Solanum esculentum
Quick description
A variety of plum tomato whose strength is as a cooking or canning tomato.
Appearance
The original San Marzano fruit is medium sized and box shaped. It often has a pointy end. The plant is indeterminate and grows in a more straggly fashion that the bushy determinate plants of many varieties. For this reason it does not adapt well to modern mechanized harvesting and so it has been superceded by determinate hybrid varieties that produce fruits that can all be harvested at the same time. The fruits have a similar shape to the original San Marzano, but are more cylindrical and have inferior taste qualities.
Eating / cooking
The tomato has a thick fruit wall (pericarp), which gives it a meaty texture, and few seeds. It has a higher sugar to acid balance than most tomatoes but with both low sugar and acid levels overall, this gives it a strong and bittersweet taste which has been compared to high quality chocolate.
The unique flavour of the San Marzano tomato has been attributed both to the qualities of the variety itself and the specific conditions it has been traditionally grown in. The traditional growing area is on the lava-rich slopes of Mount Vesuvius near Naples, where the long season and volcanic soils are supposed to be ideal for growing tomatoes
San Marzano is an excellent canning tomato and really kicked off the Italian tomato canning industry more than a hundred years ago. The reasons for its popularity are numerous. It is a great tasting tomato with a high flesh to juice ratio (so takes less cooking down), few seeds and an easily removable skin – perfect! For these same reasons it is an excellent tomato for cooking with in general.
Nutritional details
Like all tomatoes the San Marzano is high in fibre, contains vitamins A, C, E, K and B6, a variety of minerals such as potassium, magnesium and copper, and folic acid. It also contains high levels of lycopene, an antioxidant linked to the prevention of cancer.
Habitat / growing
The San Marzano vines are indeterminate and fruit throughout the growing season. They also have a somewhat longer season than other paste tomato varieties, making them more suitable for growing in warmer climates. It is partly for this reason that they once achieved such success in Italy, although the real San Marzanos are now only grown by gardeners with a passion for great tasting tomatoes.
Disease / pest resistance
The original indeterminate San Marzano varieties were sensitive to many diseases, and the arrival of the cucumber mosaic virus in the Naples region in the 1970s effectively destroyed what was left of a fragile market. Nowadays, the pseudo San Marzano tomatoes that one can find come from hybrid varieties that have inferior taste characteristics but which are resistant to many of the common diseases.
Stress tolerance
Poor
