Physiological Performance of Common Bean Seeds Treated with Bioactivator with and without Moisture Restriction

Abstract

The commonbean (Phaseolus vulgaris L.) is an important agricultural crop due to its nutritional properties. Insecticides and fungicides employed to control pests and diseases in the common bean may cause as yet unknown effects on the plant's morphology and metabolism. Bioactivators are complex organic substances, capable of exerting modification upon growth patterns, plant DNA transcription, gene expression, metabolic enzymes and mineral nutrition. Thiamethoxam insecticide has shown positive action on the enhancement of vigor expression, phytomass accretion and the promotion of deeper root systems. The aim of this work was to evaluate the effect of thiamethoxam on the physiological performance of common bean seeds. Seeds from cultivars Pérola and IAPAR Siriri were treated to thiamethoxam concentrations of 0, 100, 200, 300, 400 and 500 mL•kg −1 seed. Physiological quality was measured through tests for germination value, first count, cold test, accelerated aging and seedling shoot and root lengths, all undertaken in the presence and absence of moisture stress. Thiamethoxam stimulated the physiological performance of common bean seeds under moisture stress or in the absence of it, with levels varying according to cultivar and seed lot. The best physiological seed performance was obtained within the range of 200 mL•100kg −1 seed to 400 mL•100kg −1 seed.

Comparative effect of different insecticides on the growth and yield of soybeans

“…The taller soybean plants obtained with the thiamethoxam application might be due to the effect of the thiamethoxam molecule, which plays the role of a growth regulator (Macedo & e Castro 2011). Similar results were also found in previous studies, for instance, the seed treatment with thiamethoxam increased the plant height of cotton and okra (Preetha & Stanley 2012), rice (Almeida et al 2014a; Hum- (Almeida et al 2014b). Soybean seed treatment with thiamethoxam also enhanced the seedling vigour (Dhungana et al 2016).…”

“…Soybean seed treatment with thiamethoxam also enhanced the seedling vigour (Dhungana et al 2016). The application of thiamethoxam caused a significant increase in the fresh and dry weights of the roots and shoots of the common bean (Almeida et al 2014b). Reports show that the application of thiamethoxam in plants increases the soluble protein content, which enhances the plants ability to effectively fix carbon dioxide and, thus, accelerates photosynthesis (Preetha & Stanley 2012) and plant growth (Kirschbaum 2011), although a negative effect of thiamethoxam on a plant's metabolism, including shoot growth, was also found in a previous study (Macedo et al 2013b).…”