thumb|Physalis ixocarpa – [[MHNT]]
The tomatillo (Physalis philadelphica and Physalis ixocarpa), also known as the Mexican husk tomato, is a plant of the nightshade family bearing small, spherical, and green or green-purple fruit. Tomatillos originated in Mexico and were cultivated in the pre-Columbian era. A staple of Mexican cuisine, they are eaten both raw and cooked in a variety of dishes, notably salsa verde. The tomatillo is a perennial plant, but is generally grown for agriculture each year as if it were an annual.
Names
The tomatillo (from Nahuatl, ') Mexican groundcherry, large-flowered tomatillo, or Mexican husk tomato.
Distribution
Tomatillos are native to Central America and Mexico, having a wild growth range from Mexico to Costa Rica. The plant is grown mostly in the Mexican states of Hidalgo and Morelos, and in the highlands of Guatemala
Cultivation
History
thumb|right|Purple tomatillos (Physalis ixocarpa)
thumb|right|Green tomatillos (Physalis philadelphica)
Tomatillos were domesticated in Mexico before the coming of Europeans and played an important part in the culture of the Maya and the Aztecs, more important than the tomato. The specific name philadelphica dates to the 18th century. even though tomatillos are distributed and grown worldwide as a home-grown garden plant. Tomatillos are mainly cultivated in outdoor fields in Mexico and Guatemala on a large scale. Smaller crops are planted in many parts of the United States. In Mexico, tomatillos are planted within a wide range of altitudes. Tomatillo plants are cold sensitive. They grow best at . Below , growth is very poor.
Seedbed requirement and sowing
Transplanting is the most common practice for planting tomatillo plants. Germination occurs at . Tomatillos have diverse uses in stews, soups, salads, curries, stirfries, baking, cooking with meats, marmalade, and desserts. They may also be frozen whole or sliced.
Tomatillos can also be dried to enhance the sweetness of the fruit in a way similar to dried cranberries, with a hint of tomato flavor. The tomatillo flavor is used in fusion cuisines for blending flavors from Latin American dishes with those of Europe and North America.
Botany
Description
P. ixocarpa is often confused with P. philadelphica due to morphological similarities and the fact that neither species have had a clear type designation. Physalis ixocarpa and Physalis philadelphica have blue anthers that twist after opening, a yellow corolla with five blue-tinged spots or smudges, and a 10-ribbed calyx filled or burst by the berry. The two species differ in flower size and stigma type.
P. philadelphica grow up to and have few hairs on the stem. The leaves have acute and irregularly separated dents on the side. They are typically about in height, and can be either compact and upright or prostrate with a wider, less dense canopy. The leaves are typically serrated and can be either smooth or pubescent.
Classification
The tomatillo is a member of the genus Physalis, classified by Carl Linnaeus in 1753. Jean-Baptiste de Lamarck described the tomatillo under the name Physlis philadelphica in 1786. Other species, such as P. aeuata and P. violacea were described later. The tomatillo is also often classified as P. ixocarpa Brot. However, P. philadelphica is the most important species economically. The nomenclature for Physalis has changed since the 1950s. P. philadelphica was at one time classified as a variety of P. ixocarpa. Later, the classification of P. ixocarpa was revised under the species of P. philadelphica. Today, the name P. ixocarpa is commonly used for the domestic plant and P. philadelphica for the wild one.
thumb|283x283px|Tomatillo plant with buds, pubescent stem and serrated leaves noticeable
Flower
Flowers come in several colors: white, light green, bright yellow, and sometimes purple. Flowers may or may not have purple spots toward the center of the corolla. The anthers are typically dark purple to pale blue. Tomatillo plants are highly self-incompatible, and two or more plants are needed for proper pollination. Thus, isolated tomatillo plants rarely set fruit.
Fruit
The tomatillo fruit is surrounded by an inedible, paper-like husk formed from the calyx. As the fruit matures, it fills the husk and can split it open by harvest time. The husk turns brown, and the fruit can be ripe in several colors, including yellow, green, or even purple. The freshness and greenness of the husk are quality criteria.<blockquote>Flower types:</blockquote><gallery>
Tomatillo flower white and purple.jpg
Tomatillo flower.jpg
Starting Tomatillo Verde Flower after pollination maarten smit smitworks.jpg
Honeybee and tomatillo flowers.jpg
Tomatillo yellow flower.jpg
Happy Quinta Feira !!!!! ♥ Physalis philadelphica (8119933598).jpg
</gallery>
Varieties
There are several varieties of tomatillos, with differences in tastes, traits, and ripening colors. Some cultivars include Amarylla, Chupon, Gigante, Green Husk, Mexican, Pineapple, Purple de Milpa, Rio Grande Verde, and Yellow.
Genetic
Self-incompatibility trait
Although self-compatibility is common among wild populations, tomatillos carry self-incompatible traits. The plant, i.e., the fertile hermaphrodite, is not able to produce zygotes after self-pollination occurs. This limits the ability to improve tomatillo production regarding the seed quality and the production of varieties.
The self-compatibility gene is situated in the chromosomes of the tomatillo and is not inherited through cytoplasm. Only heterozygous plants can be self-compatible as the trait is controlled by a dominant gene.
Diseases
Tomatillo is generally a resistant crop as long as its climatic requirements are met. However, as with all crops, mass production brings exposure to pests and diseases. As of 2017, two diseases affecting tomatillos have been documented, namely tomato yellow leaf curl virus and turnip mosaic virus. Symptoms of tomato yellow leaf curl virus, including chlorotic margins and interveinal yellowing, were found in several tomato and tomatillo crops in Mexico and Guatemala in 2006. After laboratory tests, the virus was confirmed. Symptomatic plants were associated with the presence of whiteflies, which were likely the cause of this outbreak. The green peach aphid is a common pest in California, and since it readily transmits the turnip mosaic virus, this could be a threat to tomatillo production in California.