Influence of cotyledons on phenotypic characteristics in soybean seedlings

Different factors can interfere with the success of crop establishment, such as cotyledon destruction in the early stages of soybean cultivation. In this context, the influence of cotyledons on phenotypic characteristics in soybean seedlings was evaluated. The experiment was conducted in a greenhouse, and seeds of the TMG 803 cultivar, previously classified by size using sieves with circular holes (P5.5, P6.0, P6.5, P7.0, and P7.5), were used. After germination, cotyledons were removed at stages VE, VC, V1, and V2, and for each stage, three types of cotyledon removal were performed: no cotyledon removal, removal of one cotyledon, and removal of two cotyledons. The experiment followed a 5×4×3 factorial design in a randomized block layout with four repetitions, and the experimental unit was the average of two seedlings grown in a pot. The epicotyl length, internode length, petiole length of the first trifoliate leaf, and seedling height were evaluated at development stages V2 and V3. The data were analyzed by analysis of variance and subjected to the Tukey test at a 5% significance level. The influence of seed size on epicotyl length (evaluated at V2 and V3) and internode length (evaluated at V2) was more pronounced when cotyledons were removed at stages VE and VC. Internode length (evaluated at V3), petiole length (evaluated at V2), and seedling height (evaluated at V2 and V3) were influenced by seed size, independent of other factors. The number of cotyledons removed influenced the length of the evaluated traits.