Introduction to major field crops (1+1)

Climatic Requirement

Sunflower is a plant of temperate zone but varieties adapted to a wide range of environments have been developed. Sunflower is grown from 40°S to 55°N but major production is between latitudes 20 and 60 °N and 20-40°S. It can be grown to an attitude of 2,500 m above mean sea level, but gives highest oil yield below 1,500 m. Sunflower grows well within a temperature range of 20-25°C. Temperatures affect the rate of development as prolonged high temperatures reduces the time of maturity. In general, temperatures above25°Cat flowering or below 16°C reduceseed yield and its oil content.




Fig: Climatic requirement of sunflower.

Sunflower is considered to be drought tolerant but oil yield is substantially reduced if plants are stressed at peak growth period and flowering. Evenly distributed rainfall of 500 to 700 mm over the growing period and ceasing just before flowering and seed filling is ideal for good harvest. High humidity accompanied with cloudy weather and rainfall at the time of flowering results in poor seed set. Sunflower plant is susceptible to damage by lodging due to winds particularly when irrigated because of its height. Sunflower at seedling stage is highly susceptible to hail.