Report Summary : Sunflower planting

SUNFLOWER

History

The sunflower is native to Central America. The evidence thus far is that it was first domesticated in Mesoamerica, present day Mexico, by at least 2600 BC. It may have been domesticated a second time in the middle Mississippi Valley, or been introduced there from Mexico at an early date, as maize was. The earliest known examples of a fully domesticated sunflower north of Mexico have been found in Tennessee and date to around 2300 BC. Many indigenous American peoples used the sunflower as the symbol of their solar deity, including the Aztecs and the Otomi of Mexico and the Incas inSouth America. Francisco Pizarro was the first European to encounter the sunflower in Tahuantinsuyo, Peru. Gold images of the flower, as well as seeds, were taken back to Spain early in the 16th century. Some researchers argue that the Spaniards tried to suppress cultivation of the sunflower because of its association with solar religion and warfare.

 During the 18th century, the use of sunflower oil became very popular in Europe, particularly with members of the Russian Orthodox Church because sunflower oil was one of the few oils that was not prohibited during Lent, according to some fasting traditions.

Scientific Name

Sunflower (Helianthus annuus) is an annual plant native to the Americas that possess a large inflorescence (flowering head). The sunflower got its name from its huge fiery blooms, whose shape and image is often used to depict the sun. The sunflower has a rough, hairy stem, broad, coarsely toothed, rough leaves and circular heads of flowers. The heads consist of 1,000-2,000 individual flowers joined together by a receptacle base.

Sunflower seeds were taken to Europe in the 16th century where, along with sunflower oil, they became a wide-spread cooking ingredient. Sunflower leaves can be used as a cattle food, while the stems contain a fibre which may be used in paper production.

Species

·        The Maximillian sunflower (Helianthus maximillianii) is one of 38 species of perennial sunflower native to North America. The Land Institute and other breeding programs are currently exploring the potential for these as a perennial seed crop.

·        The Sunchoke (Jerusalem artichoke or Helianthus tuberosus) is related to the sunflower, another example of perennial sunflower.

·        The Mexican sunflower is Tithonia rotundifolia. It is only very distantly related to North American sunflowers.

·        False sunflower refers to plants of the genus Heliopsis.

Plant description

With sunflower, what is usually called the flower is actually a flower head (also known as a composite flower) of numerous florets, (small flowers) crowded together. The outer petal-bearing florets are the sterile ray floretsand can be yellow, red, orange, or other colors. The florets inside the circular head are called disc florets, which mature into seeds.

The florets within the sunflower's cluster are arranged in a spiral pattern. Typically each floret is oriented toward the next by approximately the golden angle, 137.5°, producing a pattern of interconnecting spiralswhere the number of left spirals and the number of right spirals are successive Fibonacci numbers. Typically, there are 34 spirals in one direction and 55 in the other; on a very large sunflower there could be 89 in one direction and 144 in the other. This pattern produces the most efficient packing of seeds within the flower head

Sunflowers most commonly grow to heights between 1.5 and 3.5 m (5–12 ft). Scientific literature, reports that a 12 m (40 ft), traditional, single-head, sunflower plant was grown in Padua in 1567. The same seed lot grew almost 8 m (26 ft) at other times and places, including Madrid. During the 20th century, heights of over 8 m have been achieved in both Netherlands and Ontario, Canada.

Special Feature

The special features of a sunflower is that we make oil from it


External features of a sunflower


pointy petals


yellow petal


big, brown (pollens) circle in middle with the petals round it


face the Sun