Response of elevated CO2 on biochemical grain quality characteristics of rice cultivar in Free Air Carbon dioxide Enrichment technology

Abstract

Study was conducted to understand the changes in grain quality parameters of tropical rice cultivar cv. Naveen, a high yielding variety of CRRI, Orissa, to elevated CO2 concentration of 600 μmol CO2 μmol–1 using Free Air Carbon dioxide Enrichment (FACE) technology at IARI, New Delhi. It was compared with ambient CO2 concentration of 370 μmol mol–1. Elevated CO2 resulted in significant changes in the yield and grain quality of rice cultivar, in comparison to plants grown under the ambient conditions. Head rice recovery, WUE, amylose content, grain elongation ratio after cooking were increased by 25.5%, 27%, 4.5% and 3.9% respectively under elevated CO2 grown plants. Reducing sugar, non-reducing sugar, total sugar content and total non-structural carbohydrate were significantly increased in grains under elevated CO2 condition. Elevated CO2 brought about significant decrease in the protein content of the grain which might be due the dilution effect. The micro nutrient of the rice-grain was also studied which showed increase in Zn and Fe content, but not up to significant level in elevated CO2 grown plants. The increased CO2 concentration in the growing environment facilitated by FACE technology may help breeders to select rice genotypes, which are responsive to the elevated CO2 with better sink potential. This study will help in developing rice cultivars positively responding to elevated CO2 up to 600 μmol mol–1 for changing climatic conditions on the basis of realistic biological data obtained using facilities close to near natural conditions