We evaluated the performance of 25 soybean genotypes sown in the off-season, to identify the morphological attributes and yield determinants for seed yield in this period. The selected genotypes are commonly used among farmers and were purchased from seed traders. Sowing of soybeans during nonpreferential times is common in the northern part of the state of Rio Grande do Sul where it is sown after maize as a late crop. The objective was to evaluate the most suitable genotypes for nonpreferential cultivation. The experiment was conducted in the agricultural crop year of 2017/2018 in Tenente Portela -RS; the experimental design was a randomized block containing 25 soybean genotypes arranged in three replicates. Analysis of variance showed significance at 5% probability; there was variability for the first pod insertion height, plant height, number of pods on the main stem, number of pods in the branches, number of branches in the main M. Peter et al. 2 stem, branch length, number of pods containing one seed, number of pods containing two seeds, number of pods containing three seeds, seed mass per fractional plant due to the pod of origin containing one, two and three seeds and seed yield. The genotypes with the highest seed yield in the off-season period in the Northwest of the state of Rio Grande do Sul were BS 2606 IPRO, BMX Magna RR and M 5947 IPRO. The productivity in kg per hectare was established with taller plants with superiority in the number of pods on the main stem, these pods being formed by two to three viable seeds.

The management of nitrogen in wheat based on biological and environmental indicators can ensure productivity with a reduction in environmental impact. The objective of the study was to develop a more sustainable management of nitrogen use in wheat, considering the dose as a fraction of the total supply based on an estimate of the maximum technical and economic efficiency, and expected grain yield, in systems of succession of high and reduced release of N-residual, during acceptable and unfavorable crop years. The study was conducted from 2012 to 2018, in Augusto Pestana, RS, Brazil. Two experiments were conducted in each agricultural year and in each rotation system (soybean/wheat and corn/wheat), one to quantify the biomass yield and the other to determine grain yield. The experimental design was a randomized block with four repetitions in a 5 x 3 factorial, for doses of N-fertilizer (0, 30, 60, 90, 120 kg ha -1 ) and ways of supplying the nutrient [full condition (100%) at the phenological stage V 3 (third expanded leaf); fractionated (70%/30%) at phenological stage V 3 /V 6 (third and sixth expanded leaf) and fractionated (70%/30%) at phenological stage V 3 /R 1 (third expanded leaf and ear differentiation)], in the ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 20 (3): gmr18903 A.B.P. Trautmann et al. 2soybean/wheat and corn/wheat succession systems with high and reduced N-residual release, respectively. More efficient use of nitrogen was obtained based on wheat grain productivity when applied at the full dose at the third expanded leaf stage. The supply of the maximum dose of nitrogen with an expectation of 3 t ha -1 ensures satisfactory productivity with reduced nutrient losses to the environment, especially in unfavorable years for cultivation, regardless of the succession system.