Lignification of the plant and seed quality of RR soybeans sprayed with herbicide glyphosate Lignifica o da planta e qualidade de sementes de soja RR pulverizadas com herbicida glifosato

Differences in levels of lignin in the plant between conventional and transgenic cultivars RR has been reported by several authors, however, there are few studies evaluating the influence of spraying of glyphosate on the lignin in the plant and RR soybean seeds. The aim of this study was to evaluate the physiological quality of RR transgenic soybean seeds and the lignin contents of plants sprayed with the herbicide glyphosate. The assays were conducted both in greenhouse and field in the municipality of Lavras, MG, in the agricultural year 2007/08. The experiment was arranged in a splitplot design with four replicates, considering the treatments hand weeding and herbicide glyphosate as plots, and five RR soybean cultivars (BRS 245 RR, BRS 247 RR, Valiosa RR, Silvania RR and Baliza RR) as splitplots. In the greenhouse, the cultivars tested were BRS 245 RR and Valiosa RR in a randomized block design with four replicates. The sprayings were carried out at stages V3, V7 and early R5 (3L/ha). The 1000 seed weight, mechanical injury, germination and germination velocity index, emergence velocity index, accelerated aging, electrical conductivity and water soaking seed test, lignin content in the seed coat, in the stem and legumes were determined. The spraying of glyphosate herbicide, in greenhouse and field, did not alter the physiological quality of seeds and the lignin contents in the plant. Diferen as nos teores de lignina na planta entre cultivares transgênicos RR e convencionais, tem sido relatadas, por vários autores, no entanto, s o escassos os trabalhos avaliando a influência da aplica o do glifosato sobre os teores de lignina na planta e em sementes de soja RR. Neste sentido, objetivou-se, com este trabalho, avaliar a qualidade fisiológica de sementes de soja transgênica RR e os teores de lignina de plantas submetidas à pulveriza o com o herbicida glifosato. Os ensaios foram conduzidos em casa de vegeta o e em campo, no município de Lavras, MG, na safra 2007/08. O delineamento experimental, utilizado em campo, foi o de parcelas subdivididas, com quatro repeti es, considerando-se como parcelas os tratamentos capina e herbicida glifosato, e, como subparcelas, cinco cultivares RR de soja (BRS 245 RR, BRS 247 RR, Valiosa RR, Silvania RR e Baliza RR). No ensaio de casa de vegeta o, utilizaram-se os cultivares BRS 245 RR e Valiosa RR, em delineamento de blocos casualizados, com quatro repeti es. As aplica es com herbicida glifosato foram realizadas nos estádios de desenvolvimento V3, V7 e início de R5 (3 L/ha). Determinou-se o peso de 1000 sementes,