Climate

1. Temperature:

• Warm and moist season loving crop grown in tropical, sub-tropical and temperate region.
• Germination: 34-36 ⁰ Generally, 30 ⁰C. (min 8-10 ⁰C)
• Growth and development: 25-30 ⁰
• Temperature of 10-15 ⁰C cause inhibition of flower formation.
• > 40⁰C has adverse effect on nodulation and N-fixation.
• Prolong high temperature affects seed viability and vigor.

2. Light:

• Highly periodic and short-day plant.
• Prolonged period of cloudy weather tends to extend vegetative phase at the expense of seed yield.
• Critical photoperiod for bud initiation: 14hr
• Maximum flower blossoming at 10-13 hr.
• At 16-18 hr photoperiod, flower do not open.
• Photoperiod effects on:

1. Induction of flowering
2. Duration and extent of vegetative phase
3. Production of viable pollen
4. Length of flowering
5. Pod filling period and maturity

3. Rainfall/Moisture:

• Is moisture sensitive crop.
• Require 500-800 mm annual rainfall.
• Rain just after sowing is harmful for germination.
• Maximum water requirement during flowering to grain filling.
• High rainfall during flowering minimizes the quantity of amino acid (especially, Aspartic acid, Glutamic acid, Lysine) in the seed.