Abstract: To deliver food security for the 9 billon population in 2050, a 70% increase in world food supply will be required. Predicted climate change emphasises the need for breeding strategies that delivers both a substantial increase in yield potential and resilience to extreme weather events such as heat waves, late frost or severe drought. Heat stress around sensitive stages of wheat development has been identified as a possible threat to wheat production in Europe. However, no estimates have been made to assess yield losses due to increased frequency and magnitude of heat stress under climate change. Using existing experimental data, we refined the Sirius wheat model and incorporated effects of extreme temperature during flowering and grain filling on accelerated leaf senescence, grain number and grain weight. This allowed us, for the first time, to quantify yield losses resulting from heat stress under climate change. We used Sirius to design wheat ideotypes optimised for CMIP5-based climate scenarios for 2050 at 6 wheat growing areas in Europe. The yield potential for heat-tolerant ideotypes can be substantially increased compared with the current cultivars in the future by selecting optimal combination of wheat traits, e.g. optimal phenology and extended duration of grain filling. However, grain yield of heat-sensitive ideotypes was substantially lower and more variable in Hungary and Spain, because extending grain filling for increased yield potential was in conflict with high temperature episodes during flowering and grain filling. Despite much earlier flowering at these sites, the risk of heat stress affecting yields of heat-sensitive ideotypes remained high. Therefore, heat tolerance in wheat is likely to become a key trait for increased yield potential and yield stability in southern Europe in the future. No Label

Abstract: This work was co-financed by NCBiR, Contract no. FACCE JPI/04/2012 – P100 PARTNER No Label

Abstract: This study deals with observed and simulated growth, development and yield of the fresh-market Thomas F1 tomato bush cultivar (Solanum lycopersicum L.) grown under open field conditions at farm scale in the Elbe lowland. The CROPGRO-Tomato model used in this study is part of the DSSAT V4.5 software. The model has been calibrated with growth analyses data from field experiments, agronomic evidence (GC UPRAVY software) and the most currently available data from the literature sources of cardinal temperatures for tomato phenology, fruit growth and photosynthesis (Tb – base temperature; Topt1 – the lowest temperature at which maximum rate is attained; Topt2 – the upper temperature at which maximum rate is sustained; Tmax – maximum temperature). The sampling plants were collected a once 14 days for analysis of basic physiological parameters: LAI (Leaf area index), LAR (Leaf Area Ratio), C (Crop Growth Rate), RGRw (Relative Growth Rate) and NAR (Net Assimilation Rate). Phenology observation was done weakly. Meteorological, soil and agro-technical parameters across the fields were monitored. The treatments were well-irrigated and well-fertilised, and therefore, no water or N stress was present.Parameters affecting leaf growth, dry biomass productions, and dry biomass of leaves, stem and generative organs from planting to harvest were calibrated against the observed data. Phenological development and growth processes such as leaf expansion and fruit growth depend on cardinal temperatures. Leaf area expansion depends on the new leaf mas produced and specific leaf area, which is influenced by light, temperature, root N uptake, and plant water status. Starting date for the simulation corresponds with transplanting date of the crop in the field, which was set at day 141. The simulation period ended at day 273, a reasonable estimate for the date when plants are stopped in practice. Initial input dry biomass at Mochov farm (Suchdol) was set to 2.25 (2.88), 1.71 (2.5) and 0.01 (0.78) grams for leaves, stem and generative organs, respectively. No Label