Abstract
With the changing climate and rainfall abrasions, there is a gradual shift in the system of rice cultivation from traditional transplanted anaerobic to aerobic system. Studies on the root anatomical and morpho-physiological traits provide insights about the adaptation under aerobic conditions. We investigated the root anatomical and morpho-physiological traits in anaerobic (BPT 5204) and aerobic (CR Dhan 202) adapted rice genotypes grown under anaerobic and aerobic conditions. It was observed that the formation of fewer aerenchyma, thickened root and larger xylem area were critical anatomical traits associated with aerobic adaptation as compared to anaerobic conditions. The root length of CR Dhan 202 significantly increased under aerobic condition which may be attributed to its aerobic adaptation in terms of water acquisition. The photosynthetic rate was significantly higher in CR Dhan 202 as compared to that of BPT 5204 under the aerobic condition. The morpho-physiological results showed that the root length, total dry weight and photosynthetic rate are the key parameters for imparting aerobic adaptation. These root anatomical and morpho-physiological traits associated with the adaptation can be used as screening criteria for phenotyping and selection of genotypes suitable for aerobic system of cultivation. Such study is expected to expedite the development of rice aerobic varieties in aerobic breeding programmes.