Abstract:
The CO2
concentration in the atmosphere is increasing and is expected to double sometime near
the middle of the next century. To determine the effects of such a CO2 increase on cotton
(Gossypium hirsutum L.) growth and productivity, experiments were conducted with open top
chambers at different CO2 concentrations like 450, 650 and 850 ppm and ambient conditions (360
ppm). Morphological attributes observed at harvest such as plant height, sympodial number and
length and leaf number increased with increase in CO2 concentration up to 650 ppm. Also
productivity attributes like number of bolls and per boll weight recorded maximum under 650
ppm of elevated CO2 atmosphere. Total dry matter production of different plant parts and harvest
index gave higher percentage for plants, grown under elevated CO2
atmosphere (irrespective of
the various CO2 concentration in the atmosphere) than the ambient. Thus, results imply that cotton
plants respond favourbly in terms of morphology and productivity indicated by increasing the
yield and biomass production up to 650 ppm. Further increase did not have any desirable effect
on cotton plant. Therefore, the recommended optimum level of CO2 concentration for cotton
growth is up to 650 ppm.