Analysis of morphological characters in soybean plants submitted to different levels of artificial shading

Abstract

Morphological characters of soybean can be influenced by shading which are occasionally caused in plants. Thus, this study aimed to evaluate the effect of different shading levels on epicotyl length, epicotyl diameter and height of soybean plants. The experiments were conducted in a greenhouse. When the plants reached the V2 development stage, measurements were taken of epicotyl length and epicotyl diameter in experiment I (conducted in autumn); and epicotyl length, epicotyl diameter, and plant height in experiments II (spring/summer) and III (summer). Each experiments were conducted in a randomized block design, in subdivided plots, with four repetitions. The plots were composed of four shading levels and the subplots were composed of eight conventional cultivars. Each experimental unit consisted of one plant grown in a 3 dm³ pot filled with soil and organic matter. The three characters evaluated in the experiment presented significant effect for the interaction cultivar x shading x sowing seasons. Epicotyl length, independent of the sowing season, increased as the shading level intensified. Both the shading level and the sowing season influenced the diameter of the epicotyl, in a general way, reducing the diameter as the shading level increased. With increasing shading rate there was an increase in plant height. Moreover, the cultivars formed statistically distinct groups for the three morphological characters evaluated.