Contribuição das ramificações e a evolução do índice de área foliar em cultivares modernas de soja

Abstract

ResumoOs objetivos neste trabalho foram quantificar a contribuição das ramificações e a evolução do índice de área foliar em cultivares modernas de soja com diferentes grupos de maturação, tipos de crescimento, semeadas em diferentes épocas e regiões produtoras de soja no Rio Grande do Sul. Experimentos de campo foram conduzidos durante o ano agrícola 2013/2014 em Santa Maria, Júlio de Castilhos e em três lavouras comerciais de soja nos municípios de Restinga Sêca, Tupanciretã e Água Santa. Avaliaram-se (data de ocorrência) os estágios reprodutivos e a determinação do índice de área foliar total, máximo, da haste principal e das ramificações em treze cultivares de soja. O índice de área foliar das ramificações contribui com cerca de 31%, 12,3% e 11% do índice de área foliar total nas cultivares determinadas, e com 20,2%, 11,8% e 9% do índice de área foliar total nas cultivares indeterminadas nas semeaduras de setembro, novembro e fevereiro, respectivamente, em Santa Maria. A maioria das cultivares apresentou uma redução no índice de área foliar total, máximo, da haste principal e das ramificações com o atraso da época de semeadura, independentemente do grupo de maturação e tipo de crescimento.Palavras-chave: Glycine max, época de semeadura, tipo de crescimento. Branches contribution and leaf area index evolution in modern cultivars of soybean AbstractThe purposes of this study were to quantify the branches contribution and the leaf area index evolution in modern cultivars of soybean with different maturity groups, stem termination, sowing in different dates and producing regions of soybean in Rio Grande do Sul. Field experiments were conducted during the growing season 2013/2014 in Santa Maria, Júlio de Castilhos and in three soybean crops on the municipalities of Restinga Sêca, Tupanciretã and Água Santa. It were carried out analysis (occurrence date) of reproductive stages and determination total, maximum, of main stem and of branches of leaf area index in thirteen cultivars of soybean. The leaf area index on the branches contributes with about 31%, 12.3% and 11% of the total leaf area index on the determinate cultivars and with 20.2%, 11.8% and 9% of the total leaf area index on the indeterminate cultivars sowing in September, November and February, respectively, in Santa Maria. Most cultivars showed a reduction on total leaf area index, maximum, of main stem and of branches with the delay on planting date, independently of the maturity group and stem termination.

Climate and Management Factors Influence Soybean Yield Potential in a Subtropical Environment

“…Data on soybean seed yield were reported on a 13% seed moisture basis. More details about the experiments can be found in Richter et al (2014) and Zanon et al (2015aZanon et al ( , 2015b. Daily weather data, including solar radiation, T min , T max , relative humidity, and precipitation were collected on-site or from nearby weather stations.…”

Soybean-corn succession according to seeding date

“…As the yield potential increases, growers invest even more in their cultivation system in anticipation of higher yields. Soybean cultivars of the indeterminate growth type have high yield potential after the onset of flowering and grow to adequate sizes even when they are sown in September (Garcia et al, 2007;Kakiuchi & Kobata, 2006;Zanon et al, 2015aZanon et al, , 2015b. Some cultivars triple in size after flowering begins.…”

Architectural Characteristics and Heliotropism May Improve Spray Droplet Deposition in the Middle and Low Canopy Layers in Soybean

“…Early-maturing soybean cultivars typically have reduced vegetative growth and are characterized with a fewer metamers due to shorter vegetative stages compared with medium-and late-maturing cultivars (Meotti et al, 2012). Growth determination is characterized by growth height ceasing when the reproductive stages start, whereas in cultivars with indeterminate growth habit, the appearance of new metamers continues during the reproductive stages (Zanon et al, 2015). BMX Ativa RR, of determinate growth habit, had the same number of metamers after flowering, showing a smaller increase in structure compared with the other cultivars.…”