High atmospheric CO₂ delays leaf senescence and crop maturity in chickpea (Cicer arietinum L.)

The effect of elevated CO₂ (550 ± 50 μmol mol⁻¹) on leaf senescence and crop maturity was studied in two varieties of chickpea viz. Pusa 1105 (Kabuli type) & Pusa 1103 (Desi type) raised inside opentop chambers and exposed to high atmospheric CO₂. Exposure to high CO₂ significantly increased rate of photosynthesis, nodules number, nitrogenase activity, photosynthetic pigments concentration and their levels in pigments profile at podding stage. Similarly high CO₂ treatment enhanced yield and its attributes in both kabuli and desi chickpea varieties and delayed crop maturity by 10 - 12 days. The study suggests that increase in source activity (photosynthetic rate) fulfilled sink demand through availability of more assimilates and N and thereby prolonged stay green character, delayed leaf senescence and crop maturity under high atmospheric CO₂.