Microsoft Word - 14-Agra_42446 1607 Bioscience Journal Original Article Biosci. J., Uberlândia, v. 36, n. 5, p. 1607-1618, Sept./Oct. 2020 http://dx.doi.org/10.14393/BJ-v36n5a2020-42446 EFFECT OF SOWING SEASON ON SOYBEAN PERFORMANCE EFEITO DA ÉPOCA DE SEMEADURA NO DESEMPENHO DA SOJA Thúlio Pereira MATTOS¹; Osvaldo Toshiyuki HAMAWAKI²; Ana Paula Oliveira NOGUEIRA2; Marlize Cristina Pinheiro LUIZ2; Fernanda Gabriela TEIXEIRA2; Décio SHIGIHARA2; Raphael Lemes HAMAWAKI3; Cristiane Divina Lemes HAMAWAKI2. 1. Universidade Federal de Uberlândia, Instituto de Ciências Agrárias, Campus de Monte Carmelo, Monte Carmelo, Minas Gerais, Brasil. thuliomattos@hotmail.com; 2. Universidade Federal de Uberlândia, Instituto de Ciências Agrárias, Campus de Uberlândia, Uberlândia, MG, Brasil; 3. Southern Illinois University Carbondale, Illinois, SIU, Estados Unidos. ABSTRACT: The soybean presents great economic expression and high impact in the Brazilian agribusiness. The productive potential of a cultivar is expressed according to the genetic constitution and the environment. The sowing time exerts influence on the agronomic traits of the soybean, impacting the yield of grains. The objective of this study was to evaluate the influence of the sowing season on the productive potential and the agronomic traits of soybean. The work was conducted at the Capim Branco experimental farm, belonging to the Federal University of Uberlândia. Twelve cultivars (UFUS 6901, UFUS 7415, BRSMG 68, TMG 801, TMG 7062 IPRO, TMG 2158 IPRO, BRS 7270 IPRO, NA 5909 RR, NS 6909 RR, CD 2737 RR, P98Y30 RR e BRASMAX Desafio RR) and four sowing seasons (October 22, November 5, December 22, 2016 and January 5, 2017) were used. The experimental design was a randomized block design with four replicates. The evaluated characters were: number of days for flowering and maturity, plant height at maturity, insertion height for the first pod, number of nodes at maturity, total number of pods, number of tainted pods and productivity. The sowing carried out in October and November contributed to obtain a larger number of nodes and a greater height of plants at maturity, which are agronomic traits favorable to higher productivity. Sowing delay seriously affected soybean yield and in the Uberlândia MG region the ideal sowing time was October 22, before the beginning of November. In the late sowing in December and January, the cultivars that had their productions less affected were the conventional cultivars BRSMG 68 and TMG 801. KEYWORDS: Glycine max. Cultural management. Predictability. INTRODUCTION In order for the soybean crop to show good growth, development and maximum productive potential, it is imperative that the soil has good physical characteristics and correction of the chemical part. In addition to soil, temperature, humidity, photoperiod, ideal sowing season, cultivation site and adequate management techniques are fundamental for the soybean to express high productivity (SILVA; SEDIYAMA; BORÉM, 2015). In soybean cultivation, when sowing is done outside the recommended season in a region, a reduction in plant height is promoted, grain productivity is impaired and the composition and physiological quality of the seeds are affected (EMBRAPA, 2011). The place where the sowing is performed is of great importance, because the soybean is a plant sensitive to the photoperiod and the amount of hours during the day is determined according to the latitude (SEDIYAMA; TEIXEIRA; BARROS, 2009). Late sowing causes a reduction of the cycle and affects the amount of radiation captured (MEOTTI et al., 2012). Losses in the range of 30 to 50% in productivity can occur in late sowing and when soybean sowing is carried out in the off-season, losses can reach 70%, compared to the ideal sowing season (CÂMARA; HEIFFIG, 2000). Each region should have its sowing season constantly evaluated for updating, since new cultivars are constantly available for cultivation in different regions (SILVA; SEDIYAMA; BORÉM, 2015). The sowing season has an impact on the production of soybeans, acting directly on the yield and quality of seeds and grains. With delay of sowing, productivity is affected (BALENA et al., 2016). It is essential to carry out studies on the sowing season for each site and regional studies, due to the variability in the environmental conditions (AMORIM et al., 2011; MEOTTI et al., 2012). In each cultivation region, suitable soybean cultivars should be used for each site and sowing Received: 08/04/19 Accepted: 30/12/19 1608 Effect of sowing… MATTOS, T. P. et al. Biosci. J., Uberlândia, v. 36, n. 5, p. 1607-1618, Sept./Oct. 2020 http://dx.doi.org/10.14393/BJ-v36n5a2020-42446 should be done at the recommendation time, combining the other cultural management techniques in the crop, in order to achieve high productivity (SILVA; SEDIYAMA; BORÉM, 2015). Studies performed by Amorim et al. (2011) in Uberlândia/MG, using seven soybean cultivars at four sowing dates, performed on October 30, November 15, December 14 and December 31, concluded that the delay of sowing influenced the architecture and behavior of plants , promoted reduction in plant height and number of days for flowering, interfering with yield and grain productivity. Balena et al. (2016), in order to evaluate the influence of the sowing time on soybean in three sowing dates (October 22, November 17 and December 11) in the municipality of Xanxerê/SC, verified a reduction in the cycle and yield of with the delay of sowing. The objective of this study was to evaluate the influence of different sowing times on the agronomic performance of soybean cultivars in the Uberlândia-MG region. MATERIALS AND METHODS The experiment was carried out in the 2016/2017 harvest, at the Fazenda Capim Branco experimental station (18 ° 52 '50.63 "S and 48 ° 20' 32.07" W and 805 m altitude), belonging to the Federal University of Uberlândia (UFU), in the municipality of Uberlândia, Minas Gerais. The region is of type Aw climate, according to the classification of Köppen (1948), rainy summer (October to March) and humid tropical climate with dry season during the winter (April to September). The meteorological data, precipitation and temperature during the conduction of the experiment are represented in Figure 1. Figure 1. Average temperature and precipitation in the months of October/2016 to June/ 2017 in Uberlândia, MG. Source: Laboratory of Climatology and Environmental Meteorology. Seeding was carried out in four seasons: October 22, November 5, December 22, 2016, and January 5, 2017. A randomized complete block design was used, with four replications, in factorial scheme 12 (cultivars) x 4 (season). The cultivars used to conduct the test were: UFUS 6901 (early and indeterminate growth), UFUS 7415 (early and semideterminate growth), cultivars of semi-early and determinate growth: BRSMG 68, TMG 801 and P98Y30 RR, BRASMAX Desafio RR (semi-early and indeterminate growth), TMG 7062 IPRO (super-early and semideterminate growth), and cultivars super-early and indeterminate growth: TMG 2158 IPRO, BRS 7270 IPRO, NA 5909 RR, NS 6909 RR, CD 2737 RR. The experiment was conducted in an area with Dystrophic Dark Red Latosol, with a clayey texture. The soil was prepared in a conventional manner, with a plowing and two harrowing before sowing, the fertilization was done according to the need of the soybean crop and the soil analysis, in the amount of 400 kg ha-1 of the formulated 02-28-18. The seeds were treated with fungicide Carbendazim and Tiram, followed by inoculation with Bradyrizobium japonicum and manual seeding. The plant populations used according to the breeders' recommendation were as follows: 240,000 plants ha-1 for cultivar P98Y30 RR; 260,000 plants ha-1 for UFUS 6901, UFUS 7415, BRSMG 68 and TMG 801; 320,000 plants ha-1 for CD 2737 RR and NS 6909 RR; 360,000 plants ha-1 for TMG 7062 IPRO, TMG 2158 IPRO, BRS 7270 IPRO and BMX Desafio RR; and 400,000 plants ha-1 for NA 5909 RR. Sowing was performed by placing 30 % more seeds and performing the thinning in V1 stage to establish the desired population. After sowing weed control was carried out with pre-emergence herbicide S-Metolachlor and Cletodim, 25 days after the emergence of soybean seedlings. The control followed with manual meadows until the end of the crop cycle in each of the four sowing seasons. At 30 days after emergence, cobalt and molybdenum, important in the biological fixation of nitrogen, were applied. Three applications of foliar fertilizer were carried out, the first one in the 1609 Effect of sowing… MATTOS, T. P. et al. Biosci. J., Uberlândia, v. 36, n. 5, p. 1607-1618, Sept./Oct. 2020 http://dx.doi.org/10.14393/BJ-v36n5a2020-42446 flowering and two biweekly applications, with the following composition: 6.5 % of nitrogen (N), 8 % of phosphorus (P2O5), 8 % of potassium (K2O), 1 % of calcium (Ca), 0.5 % of magnesium (Mg), 0.6 % of boron (B), 0.5 % manganese (Mn) and 1 % zinc (Zn) at the dosage of 1 L ha-1. The control of Phakopsora pachyrhizi and pests was carried out according to the needs of the crop (EMBRAPA, 2013). For the control of diseases was used the products with active principle of azoxystrobin, mancozeb, trifloxystrobin, prothioconazole, epoxiconazole and fluxapiroxade. The caterpillar, bug and other insect complex were controlled with acetamiprid, thiamethoxam, acephate, alpha-cypermethrin and lambda- cyhalothrin. Within the useful plot, 5 random plants were sampled, which were identified and used in the evaluation at the reproductive stage; the stages were determined by the (FEHR; CAVINESS, 1977). The following characters were evaluated: a) Number of days for flowering (NDF) and maturity (NDM): it was considered from the emergency day up to 50% of the useful part to present at least 1 open flower (R1) and when 95% of the pods in the useful part presented mature staining (R8); b) Height of the plant at maturity (HPM): Measuring the distance between the ground surface and the end of the main rod, in stage R8, using a ruler graduated in centimeters. c) Height of insertion of the first pod (HFP): distance in centimeters between the soil surface until insertion of the first pod. d) Number of nodes in maturity (NNM): Count the number of nodes of the main stem in the stage R8. e) Number of pods (NP): obtained by the total number of pods of the 5 plants sampled within the useful plot. f) Number of tainted pods (NTP): obtained by the total number of tainted pods of the 5 plants sampled within the useful plot. g) Grain productivity (PROD): obtained by means of the harvest of each useful plot, carrying out the tracing and weighing of the grains, estimating the grain productivity per hectare (kg ha- 1), with correction to 13 % of humidity according to the equation below: In which: FW: Final weight of the corrected sample; IW: Initial weight of the sample; IM: Initial moisture of the sample; FM: Final moisture of the sample (13 %). To test the differences between treatments, the analysis of variance was performed. The averages of the significant variables were grouped by the Scott Knott test for the qualitative factor, at 5 % of significance, using the statistical program Genes (CRUZ, 2016). RESULTS AND DISCUSSION In order to evaluate the effects of sowing seasons, the analysis of joint variance was performed (Table 1). It was adopted the adjustments of degree of freedom of residues when the ratio between the largest and smallest mean square of the residue was higher than 7, according to the limit suggested by Ramalho et al. (2012). Significant effects were observed for cultivars, sowing season and interaction between both factors (Table 1). The occurrence of the interaction cultivar by sowing season (C x SS), shows the differential behavior of the cultivars in relation to the phenotypes regarding of the environmental oscillations. In studies carried out by Cruz et al. (2010), the occurrence of highly significant (C x SS) interaction (P <0.01), according to the F test, was detected for the number of tainted pods (NTP) and grain productivity (PROD). According to Nogueira et al. (2013), the vegetative cycle is an important character in soybean, because it is during this period that the plant grows and accumulates leaves that reflect in the dry matter, important for obtaining high productivity. The soybean has its growth comprised in two phases, the vegetative and the reproductive, whose duration is influenced by the environmental conditions. The number of days for flowering and maturity provide the time of development of the plant in the vegetative and reproductive stages. The cultivars UFUS 7415, BRSMG 68, TMG 801 and P98Y30, sown in the months of October and November, presented higher NDF in relation to the last two seasons (Table 2), evidencing in these cultivars a tendency in the reduction of NDF as the sowing delayed. It was evidenced that for the earlier cultivars TMG 7062 IPRO, TMG 2158 IPRO, BRS 7270 IPRO, NA 5909 RR and CD 2737 RR, sowing in January provided a longer vegetative period (Table 2). Therefore, in most of the cultivars did not occur the anticipation of flowering with delayed sowing. 1610 Effect of sowing… MATTOS, T. P. et al. Biosci. J., Uberlândia, v. 36, n. 5, p. 1607-1618, Sept./Oct. 2020 http://dx.doi.org/10.14393/BJ-v36n5a2020-42446 Table 1. Brief analysis of combined variance of agronomic traits and grain productivity of 12 soybean cultivars at four sowing seasons FV GL Medium Squares NDF NDM HPM HFP Blocks/ Sowing season 12 0.45 0.64 87.40 5.14 Cultivars 11 569.59** 1603.84** 917.25** 29.71** Sowing season 3 138.86** 286.35** 15451.36** 119.69** Cultivars x Sowing season 33 20.80** 23.50** 86.07** 24.61** Error 132 0.46 0.64 39.79 5.38 >QMR/QMR/