Rice with a short seed dormancy period matures and is harvested in rainy seasons. Although the seed coat is in a state of poor air permeability due to humidity, the oxygen dissolved in rainwater can penetrate into the seeds with the water. Especially under low temperature conditions, the solubility of oxygen increases, which can quickly “wake up” the seeds with shallow dormancy and cause spike germination.
Some rice varieties generally have a short or inconspicuous dormancy period. When the temperature is high and rainy during the maturity or harvest season, spike germination is also likely to occur, affecting the yield and quality. For some hybrid rice seeds, spike germination is a prominent problem. In normal years, the spike germination rate (spike germination rate) is about 5%, and in special years (when encountering continuous high temperature and rainy weather), it can exceed 20%, seriously reducing the seed quality. In hybrid rice breeding and seed production, the commonly used sterile lines have a short dormancy period.
In addition, the application of gibberellins breaks the dormancy of seeds. In the late stage of seed maturity, spike germination is more likely to occur when there is continuous rain. The natural spike germination rate is 2%~15%, and it can reach about 70% when it is high, which directly affects the commercial quality and germination rate of seeds. How to prevent panicle sprouting during hybrid rice seed production has become an urgent problem to be solved in hybrid rice breeding and seed production.
In production, in addition to using ripening agents to treat early harvest, plant growth regulators can also be used to prolong dormancy and inhibit germination. Spraying 70mg/L S-ABA solution at the end of milk maturity in hybrid rice breeding and seed production or hybrid rice seed production F1 generation, with a dosage of 30~50L per mu, can effectively prevent panicle sprouting.
When applying, you can take 1% S-ABA WP, dilute it 150 times, and get 70mg/L, S-ABA solution, and treat the leaves.