531 AJCS 12(04):531-538 (2018) ISSN:1835-2707 doi: 10.21475/ajcs.18.12.04.pne608 Path analysis of agronomic traits in soybean cultivars with determinate and indeterminate growing habits Vinícius Jardel Szareski* 1 , Ivan Ricardo Carvalho 1 , Gustavo Henrique Demari 1 , Kassiana Kehl 2 , Guilherme Pelissari 3 , Alan Junior de Pelegrin 1 , Maurício Horbach Barbosa 3 , Tiago Corazza da Rosa 1 , Nathan Lobler dos Santos 1 , Tamires da Silva Martins 1 , Maicon Nardino 1 , Tiago Pedó 1 , Velci Queiróz de Souza 4 , Tiago Zanatta Aumonde 1 1 Universidade Federal de Pelotas, Capão do Leão, RS, Brazil 2 Fundação Pró-Sementes, Passo Fundo, RS, Brazil 3 Universidade Federal de Santa Maria, Frederico Westphalen, RS, Brazil 4 Universidade Federal do Pampa, Dom Pedrito, RS, Brazil *Corresponding author: viniciusszareski@gmail.com Abstract The aim of this study was to determine associations of cause and effect agronomic traits with grain yield in contrasting growth habits of soybean genotypes, as well as to verify the magnitude of similar behaviors in different growing environments. The trials were conducted for one crop season using randomized blocks design arranged in factorial scheme, including two growing environments (Independência - RS and Tenente Portela - RS) x four genotypes (FPS Solimões RR e FPS Júpiter RR; BRS Tordilha RR and Fepagro 36 RR, 2 indeterminate and 2 determinate growing habits, respectively) in three replications. Ten important soybean yield components were evaluated. The data were subjected to individual analysis of variance for each environment and growing habits. For each environment within habits, the phenotypic path analysis was performed among the traits. The components number of pods on the main stem, number of ramifications, number of pods in the ramifications, and number of one and two-grain pods presented contrasting results in growing environments. The number of three-grain pods is among the components mostly related to grain yield for both determinate and indeterminate growing habit genotypes, regardless of the environment. The adoption of genotypes with higher weight of thousand grains may provide satisfactory results for grain yield, regardless of the growth habit and environment of cultivation. Keywords: Glycine max L., growth environment, yield potential. Abbreviations: IGH_cultivars of indeterminate growth habit, DGH_cultivars of determined growth habit, FPI_first pod insertion height, PH_plant height, PNMS_pods number on the main stem, RN_ramification number, PNR_pods number on the ramification, NONEGP_number of one grain pods, NTWOGP_number of two grains pods, NTHREEGP_number of three grains pods, TGW_thousand grains weight, GY_grain yield. Introduction The Soybean (Glycine max L.) is characterized as the major oleaginous grown in Brazil, placing the country among the world's largest producers. It is mainly due to the extensive areas of cultivation, adaptability, and existence of many developed genotypes, the factors that contribute to the production increase (Sediyama, 2009). The knowledge of traits that most influence soybean yield is important, especially understanding expression of genotypes under different environments (Almeida et al., 2010; Szareski et al., 2016). Grain yield depends on the combination of several traits (Nogueira et al., 2012). Genotypes with contrasting growth habit have different phenotypic characteristics, where environmental conditions may act on these traits, minimizing or maximizing the genotype responses. According to Falconer (1987) significant relationships involved on correlation coefficients are justified by linkage and pleiotropism. Almeida et al. (2010) reported that environment may cause interconnection of traits, which may help or hinder the correlations. Thus, effects of correlations for environments should be analyzed. Soybean plants with determinate growing habit almost complete their vegetative cycle before the beginning of flowering. The plants with determinate habit can grow approximately 10% to 13% of their height after flowering. When the plants grow in height was stopped, thickening of the main stem occurs. In these plants, the main stem has terminal bud with racemic inflorescence. Generally, there is a branching of variable length at each node (Borém, 2000; Sediyama et al, 2009). However, indeterminate growth habit genotypes simultaneously develop their vegetative (growth) and reproductive (flowering) stages. In other words, they keep increasing height for a relatively long period after AUSTRALIAN JOURNAL OF CROP SCIENCE | SUBMITTED: 16-MAR-2017 | REVISED: 07-DEC-2017 | ACCEPTED: 08-DEC-2017