THE EFFECT OF CHITOSAN ON SOYBEAN UNDER SALINE CONDITIONS AT GERMINATION AND VEGETATIVE GROWTH STAGE

Abstract

Chitosan extracted from the shells of crustaceans is found as abundance resource in Vietnam, such as from shrimp. This is a non-toxic natural heterogeneous polymer with numerous agricultural applications, especially as bio-stimulant for growth and stress tolerance. In this study, the aim was to investigate the effects of seed soaking and foliar application of chitosan solution on agronomic performance in two genotypes of soybean (DT51 and MTD176) in the search for optimal chitosan concentration used to replace the synthetic agrochemicals. The soybean seeds were soaked in three different chitosan concentrations (500 ppm, 1000 ppm, and 2000 ppm). According to the results of this study, pre-soaking the seeds in chitosan could increase the hypocotyl length, radicle length, and fresh weight of soybean sprouts. In particular, the intermediate (1000 ppm) chitosan concentration had the greatest effect on soybean sprout growth in both cultivars, with the increase in germination rates by 20%. In addition, hypocotyl length increased by at least 1.7 times compared to the control groups. When using this concentration for foliar spray during vegetative growth, it was found that chitosan application, especially when combined with chitosan soaking for the seeds and foliar spraying with chitosan 1000 ppm, could prevent plant growth inhibition and relative water content loss from the plant tissue under saline conditions. These results suggest the potential application of chitosan as a green product in seed treatment and improvement of plant tolerance against osmotic stress factors.