Alex Cristiano Bartz

Efeito do tipo de crescimento no desenvolvimento de cultivares modernas de soja após o início do florescimento no Rio Grande do Sul

There was a change in the genetics of soybeans grown in southern Brazil from the 2000s, which requires investment in basic and detailed studies about growth and development. The purpose in this paper was to characterize the overlap period of vegetative and reproductive phases, growth in height and the emission of nodes after the beginning of flowering in determinate and indeterminate cultivars in different sowing dates and soybean regions in Rio Grande do Sul. Field experiments were conducted during the growing seasons of 2012/2013 and 2013/2014, in Santa Maria, Itaqui, Frederico Westphalen, Capao do Leao, Julio de Castilhos and in 3 commercial soybean crops in Restinga Seca, Tupancireta and Agua Santa. Overlap determination (in days) of vegetative and reproductive phases, difference in the number of nodes and height in R8 and R1 were estimated. The cultivars with indeterminate growth had higher overlap period of vegetative and reproductive phases, height growth and emission of nodes after the beginning of flowering in comparison with the determinate cultivars. The magnitude of the overlap values of vegetative and reproductive phases and of the increase in height and number of nodes after R1 ranged with the type of growth, maturity group, location, and sowing date.

Soma térmica em arroz de terras baixas irrigado por aspersão

The objective of this work was to evaluate methods of thermal time calculation and the duration of the development stages of lowland rice (Oryza sativa) irrigated by sprinkling. The experiment was conducted during three growing seasons (2010/2011, 2011/2012, and 2014/2015), with five irrigation water depths, six cultivars, and four replicates. Six methods of thermal time calculation were tested: two using the minimum basal temperature; two using the minimum and optimum temperatures; and two using the minimum, optimum, and maximum basal temperatures. For the thermal time calculation, the crop development cycle was divided into the vegetative, reproductive, and grain-filling phases. The methods that used the three cardinal temperatures showed the lowest coefficients of variation for most of the developmental phases. Both irrigation water depths and rice cultivars affected the thermal time of the development stages. The greater the water availability, the lower the duration of the development cycle. Thermal time values depend on the calculation method.