Foliar application of 6-benzyladenine after pollination improves hybrid rice seed vigor through modulating antioxidant system

Abstract

AbstractApplication of plant growth regulators emerges as one of the most reliable methods to enhance crop productivity and quality. However, knowledge is limited in seed quality of hybrid rice subjected to exogenous 6-Benzyladenine (6-BA) application during seed development. A 2-year experiment was conducted to investigate the effects of 6-BA treatment after pollination on seed vigor and its underlying regulatory mechanisms. Results showed that 6-BA treatment increased germination potential (GP) and vigor index (VI) of hybrid rice irrespective of cultivar and year, particularly with 50 mg/L. Consistently, seedling quality including seedling height, root length and dry weight was significantly enhanced under 6-BA treatment with 50 mg/L. Based on the results above, 50 mg/L was considered as the optimal concentration. Additionally, 6-BA treatment with 50 mg/L increased catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) activities, and it strongly induced the expression of OsAPX1 and OsCSD3 related to antioxidant enzyme activity at the early stage of seed emergence. Therefore, spraying 6-BA with 50 mg/L after pollination could be recommended as an agronomic practice for hybrid rice seed production with high seed vigor.