Physiological quality of wheat and soybean seeds produced under shade

ABSTRACT:

Solar radiation is essential in the photosynthetic process of plants, production of photoassimilates and seed formation. This study aimed to evaluate the physiological quality of wheat and soybean seeds produced under different levels of shading and stages during plant development. Field experiments were conducted with wheat and soybean crops in the 2018/18 and 2018/19 growing seasons, considered independent experiments. For both, a 4 x 3 factorial scheme was used, with four levels of artificial shading (0; 30; 50; 70% shade) and three shading periods (30-60; 60-90; 90-120 days after sowing - DAS, stages 20, 23 and 64 for wheat and V4, R2 and R5 for soybean, respectively). For wheat, germination was higher in seeds from plants shaded in the first (82%) and second periods (84%), and vigor (77% - accelerated aging - AA) was higher in seeds from plants shaded in the second period. For soybean, germination was higher (93%) in seeds from plants shaded in the third period, and vigor (AA) was lower in seeds from plants subjected to intense shading in the second period. It was concluded that, for wheat, shading from anthesis onwards favors germination and vigor, under levels of 30 to 40% imposed until anthesis; for soybean, seed germination and vigor are favored, mainly under 70% shading after the R5 stage.

Index terms:
germination; Glycine max; shading; Triticum aestivum; vigor