Sunflower - Origin And Botany

Sunflower (Helianthus annuus) belongs to the genus Helianthus composed of 19 species and 37 perennial species. The only cultivated sunflower, H. annuus var. macrocarpus (DC) Ckil. is said to originate from North America.

Currently it is cultivated all over the world with the largest areas being in the USA, Argentina, the Ukraine and Volga regions. Tropical type of sunflower is found in Australia and parts of Africa and Argentina. This germplasm is characterized by thick hulled seed and tall plants (2.5-3.0 m).

Botany
Sunflower belongs to the Compositae family. The sunflower plant is an erect annual herb with height ranging from 0.5 m to 3.5 m tall. The plant has a tap root which can extend down to 3 m supported by a large lateral spread of surface roots. The stem of sunflower plant can be branched or unbranched with an angular shape and a hollow to soft pitch. Leaves of the plant are oppositely positioned at the base and alternate towards the top of the stem. The shape of the leaves are variable from being cordate to ovate.
The floral part of the plant, the capitula or the head, is terminal and has a diameter ranging from 10 cm to 40 cm. Larger heads can be obtained under low plant population and higher fertilizer application. The head can be drooping or erect. The florets are hermaphrodite and aggregate into variable head sizes.

The head is surrounded by free connate bracts. On the immediate inside of the bracts are ray florets which are bright coloured, yellow to orange. In the inner part of the ray florets are disc florets which are hermaphrodite. Occasion

Depots

Chipata Depot
Stand No. 931 David Kaunda Rd
P.O. Box 510695, Chipata
Tel: +260 216 21500
Eastern province

Kapiri Mposhi Depot
Stand No. 911 Great North Rd
P.O. Box 810194, Kapiri Mposhi
Tel: +260 215 271166/74
Central Province

Kitwe Depot
Kitwe Show Grounds
P.O. Box 22196, Kitwe
Tel: +260212 226777
Coperbelt Province

Mazabuka Depot
Lubombo Rd
P.O. Box 670174, Mazabuka
Tel: +260 213 30275
Southern Province