Quality of corn seed industrial seed treatment (IST) and on-farm treatment (OFT) in Brazilian agribusiness

Seed treatments with chemical phytosanitary products can compromise mobilization of seed reserves for the seedlings under water deficit conditions. The aim of this study was to evaluate the physiological quality, the initial seedling development, and the mobilization of reserves in soybean seeds treated with phytosanitary products under water deficit. The trial was set up in a completely randomized design in a 4 × 4 factorial arrangement: chemical treatments (control, Thiamethoxam, Fludioxonil + Metalaxyl-M, and Fipronil + Pyraclostrobin + Tiophanate-methyl) × osmotic potentials (0, -0.1, -0.2, and -0.3 MPa). We analyzed the following variables: germination; hypocotyl length, root length, and total seedling length; seedling length vigor index; cotyledon dry matter weight; seedling dry matter yield; seed reserve reduction; relative dry matter yield; seed reserve reduction rate; and conversion efficiency of seed reserves into seedling dry matter. Seed quality and seedling development decline under water deficit conditions. The treatment with Fipronil + Pyraclostrobin + Thiophanate-methyl results in lower phytotoxicity. The estimated cotyledon dry matter (CDM) weight is an indicator of phytotoxicity and water deficit. Mobilization of reserves is compromised in seeds treated with insecticides, reducing the capacity of conversion of reserves into dry matter. There is an inversely proportional relationship between the reduction in conversion and the efficiency of conversion of reserves of treated soybean seeds under water deficit.

Chemical treatment and mobilization of reserves of soybean seeds under water deficit

Catão,

Pontes,

Pinheiro

et al. 2024

Dose effectiveness and quality of soybean seed treatment in Brazilian agriculture as a function of application technology

Rocha,

Carvalho,

Reis

et al. 2024

Seed treatment can be carried out in two modalities: On-Farm or via industrial treatment (IST). Evaluating the quality of the treatment is crucial, considering the percentage of coating by the phytosanitary product and the adequacy of the dose. In this context, the aim of this study was to evaluate the use of high-resolution computerized image analysis to assess the coating of treated soybean seeds. In addition, it was sought to characterize the quality profiles of coating and dose adequacy in treated seeds in the Brazilian agribusiness. 150 samples of seed treated in both modalities were collected from various soybean producers in Brazil and evaluated for the percentage of coating by means of color quantification in high-resolution image analysis and for the percentage of the active insecticide ingredient by means of High Performance Liquid Chromatography (HPLC). Image analysis was effective in quantifying coating, regardless of the dominant color. Coating correlated directly with dose effectiveness in the IST modality. Seeds treated via IST tended to have higher quality and homogeneity of treatment compared to On-Farm treated seeds, showing adequate coating and dose effectiveness. On-Farm treated seeds showed heterogeneity in treatment quality, with significant variation in coating and dose effectiveness.

Validation of the methodology of the germination test using a rolled paper plus vermiculite for treated soybean seeds

Carvalho,

Reis,

Carvalho

et al. 2024

The use of an appropriate germination method is crucial to allow expression of the germination potential of the seed lot, especially when the seeds are treated with phytosanitary products, since phytotoxicity can occur in some substrates and under some conditions and the germination values will be underestimated. In this context, the aim of this study was to evaluate the methodology of germination in a rolled paper plus vermiculite (RP+V) and the possibility of its statistical validation for routine use in laboratories. Four seed lots of two cultivars with different vigor levels and chemical insecticide treatments (control, thiamethoxam + cyantraniliprole, clothianidin + fipronil, and imidacloprid + thiodicarb, all seeds were treated with fungicide) were used. The samples were prepared and sent to 13 laboratories accredited by the Ministério da Agricultura e Pecuária (MAPA) for germination assessment with RP+V. The collected data were analyzed using statistical methodologies to assess the repeatability and reproducibility of the method, as well as its precision and accuracy. The data from normal soybean seedlings evaluated using the rolled paper plus vermiculite (RP+V) methodology show repeatability, reproducibility, precision, and accuracy within the critical parameters of 1% and 5%. The proposed methodology is reliable and can be routinely implemented in evaluation of soybean seeds, especially those treated with phytosanitary products.