Climate

• Grown up to the elevation of 1250 masl and has been collected from 2000 masl in Nepal.
• At Lower altitude (300-500 masl), higher seed yield and higher oil content is obtained.
• Optimum temperature regime for better growth is 25-30 ⁰C, but can do well up to 32 ⁰
• > 30 ⁰C encourages rapid germination, initial growth and flower formation.
• Below 18 ⁰C, germination is delayed and below 10 ⁰C, it is inhibited.
• Low temperature at flowering results in sterile pollen.
• > 40 ⁰C may reduce cross fertilization thus reducing number of capsules and lower yield.
• Differing photoperiod (more or less than 10 hrs.) or light intensity can affect seed oil and its constituents.
• Considered as drought resistant but good growth and yield can only be obtained with adequate rainfall (500-650).
• > 1000mm rainfall requires drainage.
• Rain during flowering drastically reduce yield.
• Rain during harvesting prolongs drying out of capsule.
• Repeated drying and wetting increases the degree of shattering.

Soil

• Thrives well in moderately fertile and free-draining soil.
• Best soil: sandy loam with adequate soil moisture.
• Sensitive to salinity and strong acidity.
• Soil pH 5.5-8.0 is favorable.
• Does not withstand even short period of water logging.

Varieties