This study investigated the impact of organically grown cereals on the level of free asparagine (Asn) with simultaneous consideration of grain yields and flour qualities over three growing seasons in Germany. Additionally, the relation of free Asn and acrylamide (AA) was investigated. By including free Asn results of a second trial site, heritability of the trait free Asn was calculated. Free Asn was significantly influenced by species and within species by cultivars. Rye showed the highest free Asn amount, followed by einkorn, emmer, wheat, and spelt. Replacing rye with spelt would reduce free Asn by 85%. Cultivars differed in free Asn by up to 67% (wheat), 55% (spelt), and 33% (rye). Year significantly influenced free Asn levels. Heritability was high for wheat and spelt concerning locations, but regarding years, heritability was low for wheat but high for spelt and rye. For organically grown cereals, the relation between free Asn and AA formation has never been investigated. Across species and years, a correlation of R² = 0.69 *** was found. Thus, free Asn can serve as an indicator for AA formation. In conclusion, the level of free Asn can be highly influenced by proper selection of species and cultivars.

Climate change will lead to higher frequencies and durations of water limitations during the growing season, which may affect table grape yield. The aim of this experiment was to determine the variability among 3-year old table grape cultivars under the influence of prolonged water deficit during fruit development on gas exchange, growth, and water use efficiency. Six own rooted, potted table grape cultivars (cv. ‘Muscat Bleu’, ‘Fanny’, ‘Nero’, ‘Palatina’, ‘Crimson Seedless’ and ‘Thompson Seedless’) were subjected to three water deficit treatments (Control treatment with daily irrigation to 75% of available water capacity (AWC), moderate (50% AWC), and severe water deficit treatment (25% AWC)) for three consecutive years during vegetative growth/fruit development. Water deficit reduced assimilation, stomatal conductance, and transpiration, and increased water use efficiencies (WUE) with severity of water limitation. While leaf area and number of leaves were not affected by treatments in any of the tested cultivars, the response of specific leaf area to water deficit depended on the cultivar. Plant dry mass decreased with increasing water limitation. Overall, high variability of cultivars to gas exchange and water use efficiencies in response to water limitation was observed. ’Palatina’ was the cultivar having a high productivity (high net assimilation) and low water use (low stomatal conductance) and the cultivar ‘Fanny’ was characterized by the highest amount of total annual dry mass as well as the highest total dry mass production per water supplied during the experiment (WUE_DM). Hence, ‘Fanny’ and ‘Palatina’ have shown to be cultivars able to cope with water limiting conditions and should be extensively tested in further studies.

Late detection of fungal infection is the main cause of inadequate disease control, affecting fruit quality and reducing yield of grapevine. Therefore, infrared imagery as a remote sensing technique was investigated in this study as a potential tool for early disease detection. Experiments were conducted under field conditions, and the effects of temporal and spatial variability in the leaf temperature of grapevine infected by Plasmopara viticola were studied. Evidence of the grapevine’s thermal response is a 3.2 °C increase in leaf temperature that occurred long before visible symptoms appeared. In our study, a correlation of R² = 0.76 at high significance level (p ≤ 0.001) was found between disease severity and MTD. Since the pathogen attack alters plant metabolic activities and stomatal conductance, the sensitivity of leaf temperature to leaf transpiration is high and can be used to monitor irregularities in temperature at an early stage of pathogen development.

In a two-year field trial, the effect of nitrogen (N) and sulfur (S) fertilization was investigated on grain yield, grain quality parameters, formation of acrylamide (AA), and the precursor free asparagine (Asn) in organically and conventionally produced winter wheat cultivars. In both production systems, different types, amounts, and temporal distributions of N were tested. The the effect of S fertilizer types and amounts on free Asn was only tested in the conventional farming system. Within both cropping systems, grain yield and baking quality were significantly influenced by N treatment while the effect on free Asn was only minor. Especially within the organic farming system, increasing N fertilization levels did not increase free Asn significantly. A slight trend of increasing free Asn levels with an intensified N supply was observed, especially in the presence of crude protein contents of 14% or higher. However, only N amounts of 180 kg N ha⁻¹ or higher increased the probability of high free Asn contents considerably, while N supply below that amount led to free Asn values similar to the unfertilized controls. The results indicated that good baking quality can be achieved without significantly increasing free Asn levels. In addition, cultivars affected the levels of free Asn significantly. Compared to cv. Bussard and Naturastar, cv. Capo exhibited the lowest AA formation potential at an N supply of 180 kg N ha⁻¹ while simultaneously reaching a crude protein content > 15% (conventional) and > 12% (organic). Thus, it seems that cultivars differ in their ability to store and incorporate free Asn into proteins. Over all trials, a relation of free Asn and AA was shown by R² = 0.77, while a relation of free Asn and protein was only R² = 0.36. Thus, lowering free Asn by adjusting N treatments should not necessarily affect baking quality. S fertilization within conventional farming did not change the free Asn amount or crude protein significantly, probably due to the fact that soil was not sulfate-deficient. In summary, it was evident that free Asn amounts in wheat varied widely both within cultivars and between cropping systems. In order to clearly unravel genotypic differences and their interaction with environmental factors and especially N fertilization, further research is needed.

Water limitation has a major effect on agricultural crop production, influencing yield as well as external and internal quality parameters of table grapes. Due to their high yield potential, table grapes have a particularly high risk for yield and quality losses when water is limited, but grapevines are known for high heterogeneity within cultivars. Therefore, we investigated the effect of prolonged water deficits (control, moderate, and severe deficit) during fruit development on yield and quality parameters of four different table grape cultivars (Vitis L.). Furthermore, we ranked their suitability for cultivation in areas suffering from water limitation. Up to 31% of irrigation water could be saved in comparison to the control, without significant negative effects on plant yield, berry size, or internal quality parameters, such as total soluble solids and total phenolic content. However, single bunch yield was highest at a moderate deficit and number of seeds in berries increased with the severity of deficit. Cultivar selection had the greatest influence on water consumption and mainly defined yield and quality parameters. The cultivar ‘Fanny’ produced the highest yields (195.17 g per plant), most bunches per plant (2.04), and biggest berries while cv. ‘Nero’ had the highest total soluble solids content (26.33 °Brix) and the highest total phenolic content (67.53 mg gallic acid equivalents per 100 g fresh weight). Overall, ‘Fanny’ was the most promising cultivar for cultivation under water-limited conditions during fruit development, without significant effects on yield and quality parameters.

As bakery products contribute considerably to the daily intake of the carcinogen acting substance acrylamide (AA), the aim of this study was to evaluate the impact of the management system (conventional vs. organic farming) on AA precursor levels of free asparagine (Asn) across different cultivars of the cereal species, namely winter wheat (Triticum aestivum), winter spelt (Triticum aestivum ssp. spelta) and winter rye (Secale cereale) with simultaneous consideration of gained grain yields and flour qualities. For this purpose, orthogonal field trials were established at two sites in Southwest Germany over two growing seasons (2006–2007 and 2007–2008). The results indicated a significant impact of the management system on free Asn contents in white flour. Across all species, free Asn contents in the white flour was 26% lower under organic compared to conventional farming. The impact of the management system on individual cultivars was obvious with a maximum reduction in free Asn contents of 50% in wheat cultivars if organically produced (e.g., for cultivars Ludwig, Privileg, Capo). For spelt, a significant impact of the management system was only found in 2008 with a reduction in free Asn of up to 25% if organically produced. Across both cropping systems, cultivar Franckenkorn reached the lowest levels of free Asn. For rye, a significant impact of the management system was observed only in 2007 with 33% higher Asn amounts in the conventional management system. Independent of the cropping system, rye reached the highest levels of free Asn followed by wheat and spelt. Depending on species, there was also an impact of the two systems on crude protein. The organically cropped wheat had a significantly lower level, but this was not observed for spelt and for rye only in 2007. The possible reason for the low free Asn content in the organically produced wheat flour could partially be the lower crude protein amount. Furthermore, the results indicated that lower AA contents in bakery products can be achieved by proper selection of species (e.g., 66% lower if rye is replaced by wheat) and cultivars. With an appropriate choice of the cultivar, a reduction of up to 65% was possible within wheat, along with a reduction of 44% within spelt and 12.5% within rye. In summary, the results indicated that organically produced wheat especially offers the opportunity to significantly lower the AA potential of bread and bread rolls by the choice of raw materials low in free Asn.