Potencial de rendimento de cultivares modernas de soja na região sudoeste do Paraná

Abstract

In the 2019/20 crop season, Brazil became the world's largest soybean producer and exporter. The Brazilian productive average was around3 t ha-1, however, this average is considered low, since it was already been observed yield above 11 t ha-1in the USA and 8 t ha-1in Brazil. This work aimed to quantify the potentialofsoybean yield at the field conditions, as well as its yield potential at the R5stage. The experiment was conducted in Itapejara D’oeste-PR, in the 2017/18 and2018/19 cropseasons. Five modern soybean cultivars were evaluated in four different growing environments, formed by the combination of two levels of technological inputs(optimized and producer) and two sowing times (October 10thand November 10th). The optimized level of technological inputswas carried out so that all the ideal conditions for the cultivation of soybean were achieved, in particular the water, nutritional and sanitary needs. Thelevel ofproducer input used the practices usually adopted by the farmer, following the patterns of crops in the region. The cultivars evaluated were BMX Lança IPRO, BMX Ativa RR, BMX Zeus IPRO, NS 5445 IPRO and NA 5909 RR. The trials were performed in randomized block design,with three replications. The optimizedlevel of inputreceived system fertilization (millet and black oat as predecessor crops), in addition to basic fertilization and cover, to maximize thegrainyield. In addition, drip irrigation was carried out to avoid the occurrence of hidricstress. When the plants reached the phenological stage R5, five plants per plot were selected to evaluate the number of reproductive structures. At the R8stage, the grainyield components of the same plants were evaluated, and the potential yield of the crop was estimated. The data were subjected to analysis of variance, and when significance was observed, the mean values was compared by Tukey test.Biplot analyseswere performed using GGE biplot software(ideal genotype, which won where, mean and stability, ideal environment, and association between characters). BMX Zeus IPRO showed highergrain yield and stability in different growing environments. The first sowing time(10/10) had a higher grain yield potential compared to the secondone(10/11), independent of cultivar. The optimized environments obtained higher grain yield compared to the production standard. The highest productivity (8,248 kg ha-1) and potential grain yield in R5 (19,682 kg ha-1) were obtained by cultivar BMX Zeus IPRO in the 2017/18 cropseason,in the first sowing time, in the optimized management.The first sowing season (10/10) had greater yield potential regardless of the cultivar or management adopted. The optimized environments showed higher grain yield compared to standard producer environments.