Future climatic scenarios can influence crop yield levels and induce hunger if no actions are taken. In this study, we evaluated the effect of increased temperature and CO 2 concentration on soybean yield components and biomass partitioning, that ultimately determine the crops productivity. This is conducted for two soybean genotypes that differ in their canopy and life cycles. Experiments were set as follows: a) T1 -ambient temperature and 390 molCO 2 •mol -1 , b) T2 -ambient air temperature +2.7 o C and ambient CO2, and c) T3 -ambient air temperature + 2.7 o C and 750 molCO 2 •mol -1 . Results indicate that soybean under elevated CO 2 and temperature (T3), were taller and grains weighed more than under the ambient conditions in both cultivars types. However, yield has not increased substantially due to reductions in the ratio of number of branch/plant, pods/branch and grains/branch which lead also to a lesser number of total pods and grains per plant. The increase of temperature favored the number of pods and grains on branches in the modern type cultivar, and on racemes in the old cultivar. This results in more yield in both cultivars versus plants grown in the current ambient, and higher CO 2 concentration plus temperature. In both cultivars, the pods and grains partition were higher on the ontogenically oldest four branches and racemes, with decrease in the other upper ones. In addition, the biomass allocation in vegetative tissues was higher than reproductive biomass, with intensity cultivar dependent. We concluded that in future the yield could be limited by reduction of the numbers of branches and racemes in plant, and by alteration at source-sink relation, thus, indicating that changes in canopy architecture are needed to better take advantage of the increasing concentration of CO 2 .

Abstract. A methodology for estimating and downscaling the probability associated with the duration of heatwaves is presented and applied as a case study for Indian wheat crops. These probability estimates make use of empirical-statistical downscaling and statistical modelling of probability of occurrence and streak length statistics, and we present projections based on large multi-model ensembles of global climate models from the Coupled Model Intercomparison Project Phase 5 and three different emissions scenarios: Representative Concentration Pathways (RCPs) 2.6, 4.5, and 8.5. Our objective was to estimate the probabilities for heatwaves with more than 5 consecutive days with daily maximum temperature above 35 ∘C, which represent a condition that limits wheat yields. Such heatwaves are already quite frequent under current climate conditions, and downscaled estimates of the probability of occurrence in 2010 is in the range of 20 %–84 % depending on the location. For the year 2100, the high-emission scenario RCP8.5 suggests more frequent occurrences, with a probability in the range of 36 %–88 %. Our results also point to increased probabilities for a hot day to turn into a heatwave lasting more than 5 days, from roughly 8 %–20 % at present to 9 %–23 % in 2100 assuming future emissions according to the RCP8.5 scenario; however, these estimates were to a greater extent subject to systematic biases. We also demonstrate a downscaling methodology based on principal component analysis that can produce reasonable results even when the data are sparse with variable quality.

All the synthesized compounds exhibited biological activity on seed germination. The four 2-nitromethylbenzoxazoles showed phytotoxic activity and the 5-chloro-2-(nitromethyl)benzo[d]oxazole (3b) exhibited higher inhibition than the commercial herbicide against all four plant species tested. © 2018 Society of Chemical Industry.

All of the tested compounds have been found to exhibit promising seed germination inhibition. We can conclude that lumisantonin was on average the most lethal against all plant species evaluated; however, two of the novel amides have exhibited inhibition selectivity against monocotyledons when compared with dicotyledons. © 2015 Society of Chemical Industry.

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Long-term climate change and inter-annual climate variability are events of concern to farmers and humanity. Global warming could affect agriculture in various ways and it is anticipated that agricultural systems will face great pressure from the variability of climate factors and their extreme events, which in most cases are difficult to predict, particularly extreme events of rainfall, higher dry season, hot and cold waves and their interactions. Global warming could also have some positive effects for plants such as increasing the temperature of current cold regions and increasing carbon dioxide with its positive effect on photosynthesis, growth rates, the use of water and production. Meanwhile, there are still many questions that remain about this possible future. This chapter, brings the response of plants to future conditions through specifics alterations in its components of yield on environmental conditions with enrichment of CO 2 and elevated temperature, two climatic factors, which is understood to be the factors of climatic change of greater global extent. The study of the components of yield and their alterations, can guide diverse sectors of the sciences and decision makers, in order to structure strategies of resilience in the cultivation of soybean. 2 level. This anticipated knowledge may be important for the direction of policies and research lines in various areas of agricultural sciences to develop diverse resilience strategies to climate change.The understanding of how climate influences the growth, development and production of soybean plants depends on the understanding of how the yield components respond to the variations of climate factors, which can also be elucidated if studies the plant alterations in the future atmosphere conditions. The plant production is determined by changes in yield components, in last instance. The artificial enrichment of the growth environment of soybean plants with CO 2 , O 3 and temperatures according to the forecasts on the atmospheric composition for the year 2100, can allow to know the morphophysiological responses in several levels of the plant organization, long before environmental changes occur.The study of the morphophysiological mechanisms of response of soybean plants to the ecological environment where they develop and produce grains, constitutes the basis of soybean ecophysiology.The factors of the climate (temperature, radiation, rainfall, wind and atmospheric pressure, among others), plus the physicochemical properties of the soil and the cultural practices applied in the field continuously influence the performance of the community of soya plants from germination to the senescence of the plants. Throughout the different phenological stages, the expression of stage-tissue genes defines the course of the development of the plant, the formation of the biomass and its components (roots, stems, leaves, flowers, fruits and seeds) respond simultaneously and hierarchically with the objective of completing its biological cycle and producing seeds for the...

This study explores the effect of seasonality on soil carbon efflux and pasture growth based on field and lysimeter experiments during summer-fall and winter-spring in two years. Focus is also pointed on irrigation strategies to alleviate the crop response to seasonal fluctuations in precipitation and surface temperatures. Soil respiration, soil and air temperature, leaf photosynthesis, plant dry weight and leaf area index were quantified and analyzed. It has been found significant differences in the CO2 efflux between the two growing season. Emission of soil CO2 allowed to characterize and to prioritize the temperature and rain influence in seasonal brachiaria response. During the seasons, the transient variation of CO2 efflux was highly correlated with rainfall (r = 0.87, P < 0.05), and poorly correlated with soil temperatures (r = 0.5, P < 0.05). The CO2 efflux and plant response to different level of reposition of evapotranspiration demonstrated that irrigation during fall mitigates the reduction of growth conditioned by drying soil and the lower temperatures. The lower temperatures are limiting only when the soil moisture is below 32% of the field capacity. Thus, we propose to keep the soil moisture around 50% during the fall as a key practices for mitigating the effect of seasonality and its intensification with the climate change, even more if added to management routine practices the soil and water conservation.

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