Sowing seasons maturity groups on quantitative traits in soybean

The world economic importance of soybean (Glycine max (L).) crop is consolidated, and tests to verify the best sowing season for yield gain of cultivars are demanded. The aim of this study is to analyze the effect of sowing season on soybean cultivars of different maturity groups, since the determination of the optimum time for planting soybeans and the cultivar most suited to the region under study can increase yield components and consequently productivity. The experiment was conducted in Currais, State of Piaui, Brazil, and involved evaluation of 12 treatments resulting from the interaction between: 1) sowing seasons: 11/22/2014; 11/29/2014; 12/6/2014; 12/13/2014; 12/20/2014 and 12/27/2014 and 2) two cultivars of maturity groups 8.2 and 8.6. The experiment was a randomized complete block design with four replications, in subdivided plots, and the nested effect in the plot was sowing dates. Data were analyzed using ANOVA and Tukey’s test (p £ 0.05). Interaction was significant for number of pods, pod length, dry mass of stem, dry mass of pods and number of grains per plant, but not for productivity and one thousand seed mass. In the agricultural year 2015/2016, the climatic factors worked directly on the components of soybean production, and it is possible to adopt any period of November and December for its planting.   Key words: Glycine max, climatic elements, yield components, photoperiod.