Yield potential of modern soybean cultivars under high and low input levels

O objetivo deste trabalho foi avaliar o potencial de rendimento de grãos de cultivares de soja (Glycine max) modernas submetidas a níveis alto e baixo de manejo de insumos, em diferentes datas de semeadura, na região Sudoeste do Paraná, Brasil. O experimento foi realizado nas safras de 2017/2018 e 2018/2019, no município de Itapejara D’Oeste. Cinco cultivares de soja (BMX Zeus IPRO, BMX Ativa RR, BMX Lança IPRO, NS 5445 IPRO e NA 5909 RG) foram avaliadas em quatro ambientes formados pela combinação de nível de manejo de insumos (alto e baixo) e datas de semeadura (primeira e segunda). O delineamento experimental foi de blocos ao acaso, com três repetições. As características avaliadas foram: potencial de rendimento de grãos (kg ha-1), no estádio fenológico R5; e rendimento de grãos (kg ha-1) e seus componentes, no estádio R8. A cultivar, a época de semeadura e o manejo dos insumos são determinantes para a maximização do potencial produtivo dos grãos. Na primeira data de semeadura, em outubro, a cultivar BMX Zeus IPRO apresenta melhor resposta ao manejo de alto nível, com maior potencial produtivo no estádio R5 (19.682 kg ha-1) e maior produtividade de grãos (8.248 kg ha-1), enquanto NA 5909 RG apresenta os melhores resultados com baixo manejo de insumos.The objective of this work was to evaluate the grain yield potential of modern soybean (Glycine max) cultivars subjected to high- and low-input management levels on different sowing dates, in the southwestern region of the state of Paraná, Brazil. The experiment was carried out in the 2017/2018 and 2018/2019 crop seasons in the municipality of Itapejara D’Oeste. Five soybean cultivars (BMX Zeus IPRO, BMX Ativa RR, BMX Lança IPRO, NS 5445 IPRO, and NA 5909 RG) were evaluated in four environments formed by the combination of input management levels (high and low) and sowing dates (first and second). The experimental design was a randomized complete block with three replicates. The evaluated traits were: grain yield potential (kg ha-1), in the R5 phenological stage; and grain yield (kg ha-1) and its components, in the R8 stage. Cultivar, sowing date, and input management are determinant for maximizing grain yield potential. In the first sowing date, in October, the BMX Zeus IPRO cultivar shows a better response to the high level management, with a higher yield potential in the R5 stage (19,682 kg ha-1) and a higher grain yield (8,248 kg ha-1), whereas NA 5909 RG shows the best results with the low input management

Identifying superior spring wheat genotypes through diallel approaches

Abstract Diallel crosses enable plant breeders taking decisions concerning the parental choice for developing new varieties. Recently, a large number of methodological models have been reported. The objective of this study was to investigate the relationship between different methods of diallel analysis and their associations with grain yield performance in wheat (Triticum aestivum L.) segregating populations. In this study, four methods of diallel analysis were used to estimate the general (GCA) and specific (SCA) combining abilities: (a) Griffing, (b) Multivariate analyses of diallel crosses, (c) Restricted Maximum Likelihood / Best Linear Unbiased Prediction (REML/BLUP) and d) Genotypes and Genotypes x Environments biplot (GGE biplot). Six wheat cultivars were hybridized in a partial diallel scheme and later evaluated in the along with 15 F 2 segregating populations. Griffing and REML/BLUP analysis produced equivalent results for GCA and SCA and are meaningful for identifying superior inbred lines. Multivariate diallel analysis suggested the best crosses for simultaneous improvement of traits. GGE biplot method is an effective method for visual comparisons of GCA and SCA effects. Conventional and innovative methods of diallel analysis are useful, complementary and should be applied in the selection of parents and superior crosses