Análise multivariada na peletização de sementes de alface com materiais adesivos, recobrimentos e embalagens de armazenamento

Abstract

Lettuce belongs to the Asteraceae family and stands out as the most consumed vegetable globally, with significant social and economic relevance. However, vegetable seeds exhibit characteristics that complicate their handling, such as irregular shapes, small sizes, and reduced mass, which hinder individualization during sowing. In this context, seed pelleting emerges as an efficient solution, involving the coating of seeds with dry and inert materials, usually of fine granulometry. This process aims primarily to protect seeds against pests and diseases, modify their shape and size to facilitate handling, and promote uniformity in direct sowing. Pelleting is a rising technology as it adds value to seeds and meets the demands of a competitive and demanding market. Therefore, it is important to establish an appropriate interaction and granulometry between the materials, considering the ideal proportion of ingredients. In this context, the present study aimed to evaluate the combination of coating materials and adhesives on the physiological quality of pelleted lettuce seeds, considering packaging types and storage, using PCA (Principal Component Analysis), which analyzes data in an integrated manner, identifying the most efficient combinations and contributing to the advancement of this technology in the agricultural sector. The trial was conducted at the Phytotechnics Laboratory of the Engineering and Agricultural Sciences Campus of the Federal University of Alagoas (UFAL). In the first stage, for the production of pellets, rock powders of types MB4, Ekosil, BTgran, and sururu shell powder were used as coating agents, and as adhesive agents, polyvinyl acetate (PVA) glue; sugar and wheat flour (FTA glue); and cassava starch (gum) were employed. In the second stage, naked seeds (control) and seeds pelleted with BTgran + PVA glue were stored in different packaging (paper, vacuum-sealed, and glass) for 6 months in a refrigerated environment (5°C). The seeds were placed to germinate in transparent plastic gerbox-type containers, between germitest paper, and placed in a germination chamber regulated at 20°C. One hundred seeds per treatment were used, with four replicates of 25 seeds each. In both stages, a completely randomized design (CRD) was adopted. In the first stage, a 3x4+1 factorial scheme was used, where 3 adhesive agents and 4 coating agents were combined, plus the naked seeds (control). In the second stage, seeds were stored in different packaging in a refrigerated environment (5°C). The first germination count was conducted on the fourth day after sowing, with daily counts over seven days. The variables analyzed were first germination count; germination; germination speed index; mean germination time; mean germination speed; uncertainty and synchrony of germination; seedling length and dry mass. All statistical analyses were performed using the PAST software. Data were subjected to analysis of variance (ANOVA) and principal component analysis (PCA). When the F-test was significant, means were compared in a factorial scheme using Tukey's test at 1% probability, and Dunnett's test was used when necessary. Seed pelleting has the potential to improve germination performance, but the materials used as coating and adhesive agents must be carefully selected. For pelleting, BTgran combined with PVA glue are promising materials for improving the quality and initial development of lettuce seedlings. Glass and vacuum-sealed packaging were the most efficient, preserving the integrity of pelleted lettuce seeds. Keywords: Sururu shell, Vegetables, Pellets, Rock powder.