Chitosan coating on bean and maize seeds: release of agrochemical fungicide and post-storage condition

Abstract

Chitosan is a biopolymer obtained from deacetylation of chitin; it has multiple applications in agriculture as an antifungal, soil conditioner, inducer of defense mechanisms, fruits postharvest coating, leaves and seeds, among others. The objective in this research was to evaluate the effect of chitosan coatings mixed with fungicide (dithiocarbamate) on the germination and germination speed of bean and maize seeds in storage and to determine the retention capacity of the fungicide in the coated seeds under different times of imbibition. Two coating treatments at concentrations of 0.1 and 0.5% chitosan in water, two coatings treatments at 0.1 and 0.5% chitosan supplemented with 0.5% fungicide and a coating without chitosan using only 0.5% fungicide in water were used in bean and maize seed; and as control seeds imbibed in distilled water were used; after treatments, germination percentage and germination speed were determined, also fungicide release were determined at 0, 1, 2 and 6 h of imbibition, and the effect of storage time on germination and germination speed was determined at 30, 60, 90, 120, 150 and 180 days of storage at 4 °C and 45% relative humidity. The fungicide release effect was determined by inhibiting Fusarium oxysporum conidia germination. There were no negative effects of coatings on seed germination after storage. The treatment that provided both greater retention of the fungicidal agent and released it gradually, was 0.5% chitosan mixed with fungicide concentration. Chitosan coating seeds mixed with fungicide do not cause negative changes in seed germination or germination rate.

Release of Semiochemicals: Natural Polymers

“…Due to its versatility and properties, this polymer has aroused special interest in agriculture in the release of pheromones, and the literature has recorded its use in the protection of fruits and seeds in the form of a coating, it is used in agriculture to protect fertilizers and fungicides. (Godínez-Garrido et al, 2021) The functionality of chitosan is dependent on its chemical structure, such as the presence of amino groups, but also on the molecular size, which define the physicochemical and functional properties of a polymer chain.…”

Effects on Germination and Plantlet Development of Sesame (Sesamum indicum L.) and Bean (Phaseolus vulgaris L.) Seeds with Chitosan Coatings

“…On the other hand, Zeng et al [23], report that chitosan coatings on seeds using the film technique generate a uniform protective layer, which covers the characteristic reliefs of the seed coat; these results agreed with the records in this study. Seed chitosan coating conferred homogeneity, firmness, and uniformity, as well as being colorless and compatible [22,30]; these types of coatings have shown their usefulness in postharvest storage by extending the life of the seed [21]. In turn, the film allows for water absorption, retention and the gradual release of compounds of agricultural interest mixed with chitosan, due to the physicochemical characteristics of chitosan [31].…”

“…In pearl millet seed primed with chitosan, an increased germination rate and vigor were reported (13% and 18%, respectively) [20]. Additionally, in chitosan film coatings on bean seeds, a 10% increase in germination and a 7% germination speed increase were reported [21]. In artichoke seed, the germination percentage increased by 11% when coated with chitosan film [22].…”

Effects of chitosan nanoparticles coating on delaying of seed soybean (Gycine max) deterioration

“…One of the active ingredients for seed coating is chitosan. Chitosan, as an active coating ingredient, is quite effective in maintaining seed quality in soybeans (Zeng et al, 2012), artichoke (Ziani et al, 2010), beans and maize (Godínez-Garrido et al, 2021). Some research shows that chitosan can increase salt tolerance in corn seeds (Guan et al, 2009) and wheat (Hameed et al, 2014;Wang et al, 2016a), and it can improve crop response to biotic and abiotic stress (Falcón-Rodríguez et al, 2007;Wang et al, 2016a).…”