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This study investigates the main drivers of uncertainties in simulated irrigated maize yield under historical conditions as well as scenarios of increased temperatures and altered irrigation water availability. Using APSIM, MONICA, and SIMPLACE crop models, we quantified the relative contributions of three irrigation water allocation strategies, three sowing dates, and three maize cultivars to the uncertainty in simulated yields. The water allocation strategies were derived from historical records of farmer's allocation patterns in drip-irrigation scheme of the Genil-Cabra region, Spain (2014–2017). By considering combinations of allocation strategies, the adjusted R2 values (showing the degree of agreement between simulated and observed yields) increased by 29% compared to unrealistic assumptions of considering only near optimal or deficit irrigation scheduling. The factor decomposition analysis based on historic climate showed that irrigation strategies was the main driver of uncertainty in simulated yields (66%). However, under temperature increase scenarios, the contribution of crop model and cultivar choice to uncertainty in simulated yields were as important as irrigation strategy. This was partially due to different model structure in processes related to the temperature responses. Our study calls for including information on irrigation strategies conducted by farmers to reduce the uncertainty in simulated yields at field scale. [ABSTRACT FROM AUTHOR]

Wheat interactions against fungal pathogens, such as Zymoseptoria tritici, are affected by changes in abiotic factors resulting from global climate change. This situation demands in-depth knowledge of how predicted increases in temperature and CO2 concentration ([CO2]) will affect wheat—Z. tritici interactions, especially in durum wheat, which is mainly grown in areas considered to be hotspots of climate change. Therefore, we characterized the response of one susceptible and two resistant durum wheat accessions against Z. tritici under different environments in greenhouse assays, simulating the predicted conditions of elevated temperature and [CO2] in the far future period of 2070–2099 for the wheat-growing region of Córdoba, Spain. The exposure of the wheat—Z. tritici pathosystem to elevated temperature reduced disease incidence compared with the baseline weather conditions, mainly affecting pathogen virulence, especially at the stages of host penetration and pycnidia formation and maturation. Interestingly, simultaneous exposure to elevated temperature and [CO2] slightly increased Z. tritici leaf tissue colonization compared with elevated temperature weather conditions, although this fungal growth did not occur in comparison with baseline conditions, suggesting that temperature was the main abiotic factor modulating the response of this pathosystem, in which elevated [CO2] slightly favored fungal development. [ABSTRACT FROM AUTHOR]

In this work, remote sensing-based assessments of actual evapotranspiration using METRIC integrated with a water balance model provided accurate estimates of irrigation performance. This new methodology was applied and tested in the Genil–Cabra Irrigation Scheme located in southern Spain during the 2004–2005 irrigation season. The performance indicators used, the annual relative irrigation supply (ARIS) and the irrigation water productivity (IWP), required ET input data which were calculated using either METRIC or standard FAO methodology. The new procedure that used METRIC detected overirrigation (ARIS of 1.27) in situations where the ARIS calculated with the standard FAO methodology indicated near-optimal irrigation (ARIS of 0.98). Additionally, the proposed methodology allows the estimation of the volume of applied water at the field scale. Comparisons between the ARIS and IWP values obtained from actual applied water records against those calculated with the new methodology resulted in good agreement. It is concluded that the integration of the METRIC method to calculate actual ET with a water balance model allowed the determination of performance indicators in an irrigation scheme in a reliable and accurate fashion, requiring only very limited information at the field level. [ABSTRACT FROM AUTHOR]

Flowering is one of the most critical processes in the reproductive phenology in fruit trees including olive. Under Mediterranean climate, olive flowering period normally occurs from early to late spring. Therefore, flowering time could be affected by environmental conditions such as water availability and temperature, thus influencing flower quality as well. Previous works have demonstrated the effect of genotype and environment on olive flowering, but those factors have never been compared in a single study nor their interaction evaluated. In the present work, we used a multi-environment trial established in four different agro-climatic conditions of Andalucía, Southern Spain, to test the genetic and environmental influences on flowering timing (flowering period, full bloom period, and full bloom date) and flower quality (flower number, perfect flower number and perfect flower percentage). Most of the variability found for flowering phenology parameters was due to environmental influence. On the contrary, for flowering quality parameters, most of the variability was of a genetic nature. In all cases, the genotype-environment interaction was significant. In this sense, the genotype by environment effects biplot model used to analyse the interaction showed that most of the genotypes evaluated have low stability for most of the parameters evaluated, except 'Picual' for flowering phenology parameters and 'Koroneiki' for quality. This emphasize the benefits of multi-environment trials on olive in order to select the best genotypes adapted to different environments and as a tool to face the future variability of environmental conditions caused by the climate-warming scenario. In conclusion, multi-environment trials allowed to efficiently quantify the effects of genetic and environmental factors and of their interaction on flowering phenology and on flower quality in olive. [ABSTRACT FROM AUTHOR]

Crop modelling is a critical tool for assessing the impact of climate change and for evaluating adaptation strategies to ensure the sustainability of agricultural systems. In addition to increased temperature and reduced precipitation, studying the effects of increased atmospheric CO 2 concentration ([CO 2 ]) and water stress on water efficiency of crops is highly relevant for identifying and evaluating impacts and new adaptation measures. We carried out 12 experiments with 4 faba bean cultivars under controlled conditions of [CO 2 ], temperature and water supply. An increase of [CO 2 ] from 430 to 650 ppm caused a 20% reduction in stomatal conductance under optimal irrigation supply but had almost zero effect under water stress conditions. Our study shows that the beneficial effect of a higher atmospheric [CO 2 ] on faba bean growth is counteracted by water stress, with the beneficial effect only detected when proper water management is applied. Thus, stomatal conductance appeared to be more sensitive to water stress than to elevated [CO 2 ], indicating that the beneficial effects of elevated [CO 2 ] on faba bean are largely dependent on the plant water status. This is particularly relevant in Mediterranean agricultural systems, where water shortage associated with droughts will become more frequent, even in areas of irrigation. Although differences in the response between cultivars were observed in our study when the water status was intermediate between optimal and severe drought, no single genotype among those studied will be sufficient to improve or fully guarantee yield under conditions of increasing [CO 2 ] and water shortage. Therefore, the introduction of irrigation and/or sowing date strategies currently represent the only adaptation measures. The gaps in knowledge of the response of faba bean to climate change, and the limited number of adaptation measures available highlight the need for continued research, with breeding of drought-tolerant and high-yielding faba bean genotypes as one of the most promising alternatives. • Stomatal conductance (SC) was not altered by increased [CO 2 ] under deficit irrigation. • Increases in [CO2] caused a 20% reduction in SC under optimal irrigation. • Stomatal conductance was more sensitive to water stress than to increased [CO 2 ]. • Differences in SC between cultivars were found at intermediate water status. [ABSTRACT FROM AUTHOR]

Due to the severe increase projected in future temperatures and the great economic and social importance of olive growing for vast agricultural areas in the Mediterranean Basin, accurate climate change impact assessment on olive orchards is required. The aim of this study is to assess the flowering date and the impact of mean and extreme temperature events on olive flowering in southern Spain under baseline and future climate conditions. To that end, experimental data were obtained from ten olive genotypes: six well-known olive cultivars in the region, one cultivar, 'Chiquitita', obtained via conventional breeding, and three wild olives from the Canary Islands. A site-specific model calibration was conducted resulting in satisfactory performance with an average error of 2 days for flowering date estimation under baseline and future climate conditions, and a RMSE equal to 5.5 days in the validation process. The outputs from 12 regional climate models from the ENSEMBLES European project with a bias correction in temperature and precipitation were used. Results showed an advance in the olive flowering dates of about 17 days at the end of the 21st century compared with the baseline period (1981-2010), and an increase in the frequency of extreme events around the flowering period. A spatial analysis of results identified the areas in southern Spain that are most vulnerable to climate change impact caused by the lack of chilling hours accumulation (areas located on the Atlantic coast and the south-eastern coast) and by the occurrence of high temperatures during the flowering period (areas located in the north and north-eastern areas of the Andalusian region). [ABSTRACT FROM AUTHOR]

ABSTRACT Due to the severe increase projected in future temperatures and the great economic and social importance of olive growing for vast agricultural areas in the Mediterranean Basin, accurate climate change impact assessment on olive orchards is required. The aim of this study is to assess the flowering date and the impact of mean and extreme temperature events on olive flowering in southern Spain under baseline and future climate conditions. To that end, experimental data were obtained from ten olive genotypes: six well-known olive cultivars in the region, one cultivar, 'Chiquitita', obtained via conventional breeding, and three wild olives from the Canary Islands. A site-specific model calibration was conducted resulting in satisfactory performance with an average error of 2 days for flowering date estimation under baseline and future climate conditions, and a RMSE equal to 5.5 days in the validation process. The outputs from 12 regional climate models from the ENSEMBLES European project with a bias correction in temperature and precipitation were used. Results showed an advance in the olive flowering dates of about 17 days at the end of the 21st century compared with the baseline period (1981-2010), and an increase in the frequency of extreme events around the flowering period. A spatial analysis of results identified the areas in southern Spain that are most vulnerable to climate change impact caused by the lack of chilling hours accumulation (areas located on the Atlantic coast and the south-eastern coast) and by the occurrence of high temperatures during the flowering period (areas located in the north and north-eastern areas of the Andalusian region). [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, a detailed spatial analysis of the reference evapotranspiration ( ETo) estimates provided by the MAK-Adv approach and the well-known Penman-Monteith equation ( PM-FAO56) has been carried out. MAK-Adv approach considers a regionally calibrated Makkink equation based on a combination of remotely sensed solar radiation, Rs, provided by the Land Surface Analysis Satellite Applications Facility ( LSA SAF), and numerical weather forecasts of near-surface air temperature, T2m, provided by the European Centre for Medium-range Weather Forecasts ( ECMWF). This analysis evaluated the performance of these approaches with data measured by 57 weather stations under different weather conditions within a semi-arid region, Andalusia, located at Southern Spain, and determined the role of certain physical and climate variables, such as wind speed and sensible heat advection, on the quality of the ETo estimation. For three years (2007-2009), daily Rs and T2m provided by LSA SAF and ECMWF were compared with measured data showing very good estimates, with RMSD equal to 1.47 W m−2 and 1.53 °C, respectively. Equally, ETo using MAK-Adv approach with data provided by LSA SAF and ECMWF was compared with ETo provided by the PM-FAO56 approach with measured data, obtaining RMSD = 0.69 mm, linear regression slope = 0.94, and R2 = 0.92. Although ETo estimates using both approaches were similar between them, the small differences in terms of estimation ETo were mainly correlated with the wind speed ( u) and the advection index ( Ia), depicting the critical role of these factors in the ETo estimations under semi-arid conditions, and increasing the uncertainty in ETo estimation when wind speed and/or Ia are high. The comparison of MAK-Adv and PM-FAO56 approaches has proved the usefulness in providing ETo values at a regional scale and detecting those areas where the ETo estimation had higher uncertainty, contributing to an improvement in water management. [ABSTRACT FROM AUTHOR]

• Advanced sowings compared to traditional may raise durum wheat yield in Mediterranean. • Water stress reduction and longer grain filling were the major factors for yield increase. • Short-cycle cultivars were less affected by hot and dry Mediterranean conditions than medium-long cultivars. Durum wheat is one of the most important crops in the Mediterranean basin. The choice of the cultivar and the sowing time are key management practices that ensure high yield. Crop simulation models could be used to investigate the genotype × environment × sowing window (G × E×SW) interactions in order to optimize farmers' actions. The aim of this study was to evaluate the performance of the wheat model SiriusQuality in simulating durum wheat yields in Mediterranean environments and its potential to explore the G × E×SW interactions. SiriusQuality was assessed in multiple growing seasons at seven sites located in Italy, Spain and Morocco, where locally adapted cultivars were grown. The model showed good ability in predicting anthesis and maturity date (Pearson r >0.8), as well as above ground biomass and grain yield (6 % < nRMSE < 18 %). The model was then used to find the optimal 30-day sowing window to maximize grain yields at four sites, two were located in Italy (Florence, Foggia), and the other two were in Spain (Santaella) and Morocco (Sidi El Aydi) respectively. Among the cultivars, on the average between all sowing window, Amilcar had the best performance in Foggia (+33 % compared to the traditional cultivar Simeto) and in Sidi El Aydi (+22 % compared to Karim), Karim in Florence (+19 % compared to Creso) and in Santaella (+6 % compared to Amilcar). Instead Creso and Simeto showed the lowest production at all locations. The results showed that an earlier sowing window compared to the traditional one would have a positive effect on wheat yields in all environments tested, because of increased maximum leaf area index, grain number and size, and grain filling duration. Moreover, with earlier sowing, grain filling coincides with higher soil water availability, reducing the water stress and increasing the accumulation of dry mass in grains. In cooler and wetter locations, cultivars characterized by higher leaf area index and radiation use efficiency had the higher number of grains, while in the hottest and driest locations, short-cycle cultivars with high grain dry matter potential (e.g. through enhanced "stay green" capacity) should be preferred. [ABSTRACT FROM AUTHOR]

• Olive phenology in Subtropical climate is different from the typical Mediterranean. • The length of olive flowering phenology is greatly influenced by climatic conditions. • The main effect of lack of winter chilling is an asynchronous burst of olive flowers. • Length of flowering period should be included in future olive phenology modelling. Olive flowering phenology is highly affected by climatic conditions. Phenological models have been developed to forecast flowering date on olive mainly based on temperature. These models have used flowering datasets collected from trees growing under Mediterranean climatic conditions. In most of the cases, in those conditions, chilling requirements are rapidly fulfilled. In other cases, artificial modifications of the climatic conditions has been practiced by using growth chambers. In the present work, we compare the flowering phenology of 'Picual' and 'Arbequina' olive cultivars in Mediterranean conditions of Andalucía, Southern Spain, with those in Tenerife, Canary Islands with Sub-Tropical climate. The climatic conditions of Tenerife respect to Andalucía promoted an earlier flowering date but, more importantly, a much longer flowering period. This is mainly produced by an asynchronous flowering bud burst that will generate negative impacts on yield and quality. Quite likely, those differences on flowering phenology between Andalucía and Tenerife climatic conditions are mainly caused by the lack of winter chilling in Tenerife locations. Based on those results, we propose that future works studying the effect of lack of winter chilling on olive should include the length of the flowering period as a parameter to be modeled. Besides, studies on natural climatic conditions with warm winters, as the one here reported, are needed to really assess the effect of winter chilling on olive. [ABSTRACT FROM AUTHOR]

Flowering is one of the most critical processes in the reproductive phenology in fruit trees including olive. Under Mediterranean climate, olive flowering period normally occurs from early to late spring. Therefore, flowering time could be affected by environmental conditions such as water availability and temperature, thus influencing flower quality as well. Previous works have demonstrated the effect of genotype and environment on olive flowering, but those factors have never been compared in a single study nor their interaction evaluated. In the present work, we used a multi-environment trial established in four different agro-climatic conditions of Andalucía, Southern Spain, to test the genetic and environmental influences on flowering timing (flowering period, full bloom period, and full bloom date) and flower quality (flower number, perfect flower number and perfect flower percentage). Most of the variability found for flowering phenology parameters was due to environmental influence. On the contrary, for flowering quality parameters, most of the variability was of a genetic nature. In all cases, the genotype-environment interaction was significant. In this sense, the genotype by environment effects biplot model used to analyse the interaction showed that most of the genotypes evaluated have low stability for most of the parameters evaluated, except 'Picual' for flowering phenology parameters and 'Koroneiki' for quality. This emphasize the benefits of multi-environment trials on olive in order to select the best genotypes adapted to different environments and as a tool to face the future variability of environmental conditions caused by the climate-warming scenario. In conclusion, multi-environment trials allowed to efficiently quantify the effects of genetic and environmental factors and of their interaction on flowering phenology and on flower quality in olive. [ABSTRACT FROM AUTHOR]

Olive is an evergreen tree species that is cultivated in 10.8 million hectares all over the world, being more than 2.5 million hectares planted in Spain (FAO, 2017). Andalusia, in Southern Spain, is the main region of the world both by surface and production. This region is characterized by a great diversity of soil types and weather conditions. For this reason, the complete assessment of the Andalusian olive groves is complex. Flowering stage is a critical phase for olive yield and irrigation requirements, and then, the correct assessment of the factors that affect to flowering date is an outstanding factor in the improvement of crop management under different climatic conditions. This has a significant relevance considering the concerns associated to climate change and the profit reduction of the traditional Mediterranean agriculture. Temperature is a key factor in the flowering of olive trees and therefore has a critical impact on yield. It is therefore essential to know the components that affect to blooming in order to identify adaptation measures for Mediterranean olive orchards to the future climate.Previous studies evaluated the variation in blooming dates in several olive trees varieties, located under different conditions (Navas et al., 2017) at 4 test fields located in different agroclimatic conditions in Andalusia: Gibraleón (Huelva), Antequera (Málaga), Baena (Córdoba) and Úbeda (Jaén). This study complements the above mentioned in terms of including four new varieties ('Ocal', 'Changlot Real', 'Carrasqueño de Alcaudete' and 'Arbosana') and additional seasons. Thus, we improved the characterization of the fields (mainly, soil properties and weather variables) and monitored the phenological status periodically during the 2016/2017 and 2017/2018 seasons. In all cases date of beginning, full and end of flowering was scored as well as the length of the flowering period.In general terms, blooming date varies around one month between the different seasons, being 'Ocal' and 'Picual' varieties the earliest and the latest, respectively in all the locations. Nevertheless, a gradient within the regions was identified from west to east, regarding the beginning of blooming. These is likely due to the differences measured in the weather and edaphic variables (and their interactions), which have shown a relevant effect on this key phenological phase of the crop.References:Fao, 2017. http://www.fao.org/faostat/en/#data/QCNavas-López, et al. (2017) Flowering phenology and flower quality of cultivars' Arbequina', 'Koroneiki' and 'Picual' in different environments of southern Spain. In International Symposium on Flowering, Fruit Set and Alternate Bearing 1229 (pp. 257-262). [ABSTRACT FROM AUTHOR]