Leaf development and growth of selected sugarcane clones in a subtropical environment

The objective of this work was to compare phyllochron and leaf area on individual stalks of selected sugarcane (Saccharum officinarum) clones grown in a subtropical environment. A two-year field experiment was carried out in Santa Maria, RS, Brazil, during the 2007/2008 and 2008/2009 growing seasons. Three sugarcane clones were used: IAC 822045 (early), SP 711406 (median) and CB 4176 (late), in a complete randomized block design, with four replications. Expanded leaf and total leaf (tips) number were determined, and expanded leaf area was measured. The phyllochron (ºC day leaf-1) based on expanded and tip leaf number was estimated, using 10ºC as base temperature. Allometric relationships between individual area and number of expanded leaves were fitted. Phyllochron was analysed as a four-factor experiment: clone, growing season, phyllochron phase, and phyllochron type. The early clone had the greatest potential for growing in a subtropical climate because of higher leaf output and leaf area.

Maize leaf development under climate change scenarios

The objective of this work was to simulate maize leaf development in climate change scenarios at Santa Maria, RS, Brazil, considering symmetric and asymmetric increases in air temperature. The model of Wang & Engel for leaf appearance rate (LAR), with genotype-specific coefficients for the maize variety BRS Missões, was used to simulate tip and expanded leaf accumulated number from emergence to flag leaf appearance and expansion, for nine emergence dates from August 15 to April 15. LAR model was run for each emergence date in 100-year climate scenarios: current climate, and +1, +2, +3, +4 and +5°C increase in mean air temperature, with symmetric and asymmetric increase in daily minimum and maximum air temperature. Maize crop failure due to frost decreased in elevated temperature scenarios, in the very early and very late emergence dates, indicating a lengthening in the maize growing season in warmer climates. The leaf development period in maize was shorter in elevated temperature scenarios, with greater shortening in asymmetric temperature increases, indicating that warmer nights accelerate vegetative development in maize.

Simulação do rendimento de grãos de arroz irrigado em cenários de mudanças climáticas

O objetivo deste trabalho foi simular o rendimento de grãos de arroz em cenários de mudanças climáticas com aumento da atual concentração de CO2 na atmosfera e da temperatura média do ar em Santa Maria, RS, e verificar as implicações nas recomendações de época de semeadura. Foram utilizados cenários de mudanças climáticas, para os próximos 100 anos, com o dobro da quantidade de CO2 e com aumentos de temperatura do ar de 1, 2, 3, 4 e 5°C. O rendimento de grãos da cultura do arroz foi simulado com o modelo InfoCrop. As simulações foram realizadas para três cultivares de arroz (IRGA 421, IRGA 417 e EPAGRI 109) em sete datas de semeadura, com intervalos mensais, de 20 de julho até 20 de janeiro. Um aumento no rendimento de grãos de arroz irrigado foi observado nos cenários de mudanças climáticas simulado para as três cultivares, com maior incremento na muito precoce (IRGA 421) e menor na de ciclo longo (EPAGRI 109). Se as mudanças climáticas se confirmarem, o período de semeadura recomendado atualmente para cultivares de arroz irrigado deverá ser ampliado.

Rellevància de la competència transversal Capacitat d'aprenentatge i responsabilitat en l'àmbit de Ciències de la Salut

Se determina la relevancia y la modalidad de trabajo (Presencial, semipresencial o no presencial) del conjunto de las cinco sub-competencias (Capacidad de análisis y de síntesis - Aplicar conocimientos a la práctica - Resolver problemas y tomar deci-siones - Capacitado para adaptarse a nuevas situaciones - Asumir responsabilida-des), ligadas a la competencia transversal Capacidad de aprendizaje y responsabili-dad, en los estudios de grado de Ciencias de la Salud de la UB y URL.

Rellevància de la competència transversal Capacitat d'aprenentatge i responsabilitat en l'àmbit de Ciències de la Salut

Se determina la relevancia y la modalidad de trabajo (Presencial, semipresencial o no presencial) del conjunto de las cinco sub-competencias (Capacidad de análisis y de síntesis - Aplicar conocimientos a la práctica - Resolver problemas y tomar deci-siones - Capacitado para adaptarse a nuevas situaciones - Asumir responsabilida-des), ligadas a la competencia transversal Capacidad de aprendizaje y responsabili-dad, en los estudios de grado de Ciencias de la Salud de la UB y URL.

Rellevància de la competència transversal Capacitat d'aprenentatge i responsabilitat en l'àmbit de Ciències de la Salut

Se determina la relevancia y la modalidad de trabajo (Presencial, semipresencial o no presencial) del conjunto de las cinco sub-competencias (Capacidad de análisis y de síntesis - Aplicar conocimientos a la práctica - Resolver problemas y tomar deci-siones - Capacitado para adaptarse a nuevas situaciones - Asumir responsabilida-des), ligadas a la competencia transversal Capacidad de aprendizaje y responsabili-dad, en los estudios de grado de Ciencias de la Salud de la UB y URL.

Long-term changes in rice development in Southern Brazil, during the last ten decades

The objective of this work was to test long-term trends in the duration of rice development phases in Santa Maria, RS, Brazil. The duration from emergence to V3 (EM-V3), emergence to panicle differentiation (EM-R1), emergence to anthesis (EM-R4), and emergence to all grains with brown hull (EM-R9) was calculated using leaf appearance and developmental models for four rice cultivars (IRGA 421, IRGA 417, EPAGRI 109, and EEA 406), for the period from 1912 to 2011, considering three emergence dates (early, mid, and late). The trend of the time series was tested with the non-parametric Mann-Kendall test, and the magnitude of the trend was estimated with simple linear regression. Rice development has changed over the last ten decades in this location, leading to an anticipation of harvest time of 17 to 31 days, depending on the cultivar maturity group and emergence date, which is related to trends of temperature increase during the growing season. Warmer temperatures over the evaluated time period are responsible for changing rice phenology in this location, since minimum and maximum daily temperature drive the rice developmental models used.