Physiological effects of stress-related enzymes and reactive oxygen species in chilli (Capsicum annum L.) genotypes under waterlogging conditions

The experiment involved two sets and was conducted to investigate the responses of various chilli genotypes to waterlogging in the net house of the Department of Plant Physiology, College of Agriculture, OUAT, Bhubaneswar. Initially, eight chilli varieties underwent trials exposed to different durations of waterlogging. Notably, local varieties Barkote and Daringbadi exhibited exceptional resilience regarding adventitious root formation, yellowing of leaves and wilting %. These were further studied in the second experiment where the plants of local genotypes, when subjected to waterlogging for specific durations of 2 h, 4 h, 6 h and 8 h, displayed decreased growth with sudden wilting syndrome, a physiological disorder. This short exposure to waterlogging led to an oxidative burst, resulting in elevated levels of Reactive Oxygen Species (ROS) like H2O2 and O2-and intensified membrane peroxidation and production of malondialdehyde (MDA) and superoxide dismutase (SOD) played a vital role in ROS defence, leading to higher antioxidant enzyme levels in Daringbadi, including catalase, peroxidase, SOD and glutathione peroxidase 66 %, 50.4 %, 35.7 % and 51.5 % higher, respectively. Glutathione reductase and ascorbic acid oxidase activities were 49.4 % and 39.2 % higher in barkote, revealing differing waterlogging resistance mechanisms in both varieties. Furthermore, the experiment showed that Barkote and Daringbadi experienced reduced yield components compared to their non-stressed counterparts. Daringbadi exhibited a more significant reduction in yield of 19.8 % than Barkote. Our study found that local chilli pepper cultivars (Daringbadi and Barkote) had a relatively tolerant ability to short-term waterlogging for less than 12 h than all the tested varieties, and Barkote excels over Daringbadi. The study suggests that chilli breeding should be considered between released and local species to expand genetic sources.